Wikipedia talk:WikiProject Elements

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IUPAC on group 3

For future reference, I note the IUPAC project here. Methinks this is worth a top mentioning.

“ This project will deliver a recommendation in favor of the composition of group 3 of the periodic table as consisting either of

the elements Sc, Y, Lu and Lr, or

the elements Sc, Y, La and Ac.

The task group does not intend to recommend the use of a 32-column periodic table or an 18-column. This choice which is a matter of convention, rather than a scientific one, should be left to individual authors and educators. The task group will only concern itselve with the constitution of group 3. Once this is established, one is free to represent the periodic table in an 18 or 32 column format.

— IUPAC (18 December 2015). "The constitution of group 3 of the periodic table".

”

Notes:

• Chair of the project is Eric Scerri.
• Apparently IUPAC has abandoned the Sc/Y/*/** option altogether. Group 3 does not consist of Sc, Y, all lanthanides and actinides (would be 32 elements in total).
• It states that the presentation form (in 18- or 32 columns) is not related to the content (especially not the group 3 constitution).
• It nicely uses the descriptive "32-column" wording, not the ambiguously defined "long form" wording. -DePiep (talk) 08:30, 25 November 2016 (UTC)

General notes, added later:

• The outcome will possibly imply a change of the periodic table structure, away from the 1945 Seaborg version (that puts all lanthanides and actinides in group 3). That would be huge in PT history. -DePiep (talk) 08:55, 26 December 2016 (UTC)
• When announcing the four new element names and symbols, IUPAC has published this this version, dated 28 November, 2016. It is still showing the Seaborg Group 3 constitution (Sc/Y/*/**). -DePiep (talk) 08:48, 18 January 2017 (UTC)
• The RfC on group 3 has closed. -DePiep (talk) 08:48, 18 January 2017 (UTC)

Thank you DePiep, for posting this here. On a slow day, I happened upon this "news item(?)" discussing the placement of Lr in the periodic table. It isn't very good but is interesting in that it mentions Jensen's, Lavelle's and Scerri's views on the placement question (but see also here, for a different opinion by Jensen), and quotes Jan Reedijk, president of IUPAC's inorganic chemistry division, on how long it might take IUPAC to make up their mind, once Scerri's project team makes their recommendation:

Reedijk, of IUPAC, looks forward to Scerri's report. But he cautions that IUPAC's deliberations will probably be slow. When IUPAC proposed modifying the periodic table's column numbering in 1985, it took about five years to decide and another 10 to 15 years for chemists to adopt the changes, Reedijk says.

Joy. Sandbh (talk) 04:26, 26 December 2016 (UTC)

Interesting link indeed (from May 2015, so when the Lr ionization energy was first published. Scerri's project team had not even started then).

Wrt the "5+15 years" remark, I can say this. Back when the group numbers changed, there was an alternative valid set (two even: US and European style). These sets are still valid. Current group numbering was just an improvement/change, that took a long time to replace because there was no urgent need to do so. However. In the case of Group 3 constitution, the current form will be declared invalid. Today no source can be found to claim that group 3 has those 32 Sc/Y/*/** elements. So it must be replaced into one form or another. Now, even the latest IUPAC PT (28 November 2016, adding the four new names) says old style Sc/Y/*/** because the Scerri-project has not published yet. Unless the Scerri-project has some surprise up their sleeve, when they publish the Sc/Y/*/** graphic will be illegal. Publishing it will be a scientific fraud. IUPAC will have to publish a new version, or two.

We at Wikipedia can easily adopt the new version(s). For reasons we know, we are free to pick a preferred version etc. Enwiki will publish a correct new version. When, over 15 years, the scientists finally have agreed on the obvious, all young scholars (under 25 y) already will have learned the correct, legal version(s) by heart—from us. -DePiep (talk) 08:44, 26 December 2016 (UTC)

About IUPAC writing 'itselve'

<rant>Has no one else cringed at "The task group will only concern itselve [sic] ..."? I checked, and it is actually on the IUPAC website. By my en-us ear, it should be "The task group will only concern itself ..." but it may be that en-uk would prefer "The task group will only concern themselves ..." but unless I'm missing something, "itselve" would )be equally unacceptable in any ENGVAR. Does someone have a contact who could suggest they fix this? It certainly makes the IUPAC look to be a bit illiterate. </rant> YBG (talk) 18:37, 26 December 2016 (UTC) Send an email to the task group Chair, Eric Scerri. Sandbh (talk) 21:35, 26 December 2016 (UTC) Why didn't I think of such an obvious thing? (Probably 'cause I was wrapped up in my rant.) I'll e-mail him in a day or two. YBG (talk) 21:47, 26 December 2016 (UTC) I am beginning to get why such a process can take 15 year. -DePiep (talk) 00:17, 27 December 2016 (UTC) I checked, and it is actually on the IUPAC website. [YBG]. Y'know YBG, I do can copy/paste. -DePiep (talk) 02:04, 14 January 2017 (UTC). Like I generally can also, but then my cursor goes all weird on my and I wind up typing someplace I don't expect, which is fine when I notice it but when I don't, I've been known to unintentionally edit other folks contributions to talk pages.  Dislike . YBG (talk) 02:20, 14 January 2017 (UTC) Allow me to make this singular winning point. On average, 45% of my 1000 edits are spelling fixes. -DePiep (talk) 02:40, 14 January 2017 (UTC) Do you have a WP:RS for that factoid? Or is it WP:OR? Oh, wait a minute. It doesn't meet WP:N. All I can say is I'm glad no one is keeping a running count of the spelling errors I create. Cheers! YBG (talk) 04:20, 14 January 2017 (UTC)

• Does someone know a good source (wiki article) for that "Glenn T. Seaborg" (1945) table I keep mentioning? The one when Seaborg first puts the LN and AN over there, that way? -DePiep (talk) 02:57, 14 January 2017 (UTC)

There is a good (non-wiki) source here (p. 128). He appears to treat the lanthanides as Ce–Lu and the actinides analogously (Th onwards). Sandbh (talk) 06:02, 17 January 2017 (UTC)

Interesting enough. This is the first time that I can think of when I see not only hydrogen but also aluminum taking two positions in the table instead of the usual one. The intent is clear; that's just interesting. Thank you for sharing.--R8R (talk) 21:37, 19 March 2017 (UTC)

Thanks. -DePiep (talk) 21:11, 16 February 2017 (UTC)

(Intentionally undated post, just to keep this from being archived. DP).

Infoboxes: split table Isotopes into new infobox

This is about our 120 element infoboxes (for example infobox U). Below I propose to split the isotopes table into a separate, new infobox. It would remove the very detailed and not-in-articlebody data from the top infobox. The new infobox can go into the ==Isotopes== section, and also as a regular infobox in page "Isotopes of <element>". I've arranged the proposal/discussion into: 1. Changes in infoboxes and articles, 2. What would the new infobox be like?

My hat tip for this brilliant information approach goes to YBG. Thinking out of the box—into another one.

TL;DR

• For all 120 {{Infobox element}}s, copy/paste table section "Most stable isotopes" into new {{Infobox <element> isotopes}}. Then put this new infobox in article section ==Isotopes==, and remove this table from the top infobox. Also add it as top infobox in [[Isotopes of <element>]]. No other changes in Infobox element. Demo for U: Uranium/sandbox (article), isotopes of U, new isobox U. Discussed in two talk subsections: #Moving data, #The new infobox.

Please do not discuss in this intro section. Use subsections instead. -DePiep (talk) 19:23, 27 December 2016 (UTC)

Moving data

This section is about proposed information changes between infoboxes and articles. The new infobox itself is discussed #below

Per WP:INFOBOXPURPOSE (the paragraph is worth reading), the infobox should summarize information that is already in the article body. There is some leeway for this (we want the melting point in there, even if it is not described in the article body text). But there is a treshold for less relevant data.

Step Create. I propose to create a new infobox for the 'most stable isotopes' table ('Isobox' for short; × 120 elements). This step is a preparation (no content changes happen). This infobox is described in #The new Infobox <element> isotopes.

Step Remove. Now I do claim that the isotopes table does not belong in the infobox. For starters, they are not mentioned (that specific) in the article, so why should the infobox 'summarize' them? Then, the table adds too much detail, both in number of isotopes and in data columns. Also, the total list of infobox parameters is very, very long (which is too long to be an effective summary of the article). And compared to the other data present, I see few or little information that could be removed instead of this table (info with lower rights to be there). Other data can be up for discussion too, at some other time and place. Concluding, I propose to remove the isotopes table section from the element infoboxes.

Step Add. The new Isobox is added to the element's ==Isotopes== section. For any element the steps Remove and Add are performed at the same moment, so there will always be exactly one table in the article. Also, the Isobox is to be added to the article "Isotopes of <element>" (120 P), as a regular top infobox.

What will not change. Apart from the disappearing isotopes section, {{Infobox element}} will not change per this proposal. Also, the mentioning of isotopes in the lede is unchallenged (a good lede should not/will not require rewriting for this removal). The isotopes table itself will not change, because the Isobox is first of all a cut-and-paste copy. To keep this complex data move (and its discussion) manageable, content/structural changes in the 'most stable isotopes' table are not considered. Such improvements can be initiated once the new 120 Isoboxes are alive & well.

-DePiep (talk) 19:23, 27 December 2016 (UTC)

Comments on Moving data

Looks like a good approach - and thanks for the hat tip. One idea that might remove a bit of the dependencies: Initially, create an empty isobox and add it to the ===Isotopes=== section. This should make zero difference in the appearance of the article itself. This could be done to all of the elements before anything else is done. Then element by element all that is required is to simultaneously remove stuff from the element infobox and add it to the already-created isotope infobox, without needing to do anything to the article itself. YBG (talk) 19:36, 27 December 2016 (UTC)

tangential discussion of process

That assumes we can make that Isobox right in one edit... I prefer some harmless tweaking time for these boxes, both individually and federal (master template). Then change the article in two simple edits. More important is that we must be sure that each article can receive that new box. Both by content and by layout (eg, FA's have nicely spread images, adding this table could disturb that. eg, some articles have no ===Isotopes=== section at all, they need rewording?). It must be ok for all 120. -DePiep (talk) 22:25, 27 December 2016 (UTC) Yea, I can see that. But what about using template sandboxes as follows 1. Create empty isoboxes for all elements 2. Copy empty isobox to its respective sandbox for all element (depends on 1) 3. Copy all element infoboxes to their respective sandboxes 4. Add transclusion of isobox in every element article (adding ===ISOTOPES=== as needed) (depends on 1). 5. Move data from element infobox sandboxes to element isobox sandboxes (depends on 2,3) 6. Validate that a given element (depends on 4,5) 6a. Edit element isobox and copy from sandbox but do not save. Preview element article and modify ===Isotopes=== if needed for formatting. 6b. Edit element infobox and copy from sandbox but do not save. Preview element article and modify lede if needed for formatting. 7. Implement for a given element by copying infobox and isobox from their sandboxes (depends on 6) Steps 1-4 can be done for all elements and in any order except that for a given element, 1 must be done before either 2 or 4. Steps 5-6 can be done iteratively as a part of the isobox design. If you need to go back to the drawing board, just redo steps 2 and 3. Step 7 should probably wait until 6 is completed for all elements. Not trying to tell you what to do, but thought these might help you formulate your own ideas. YBG (talk) 00:35, 28 December 2016 (UTC) Will read this in detail later on. Edit sequence not major, and no bottleneck (because it's just editing, not content). Way more important is whether we can be sure that this change can happen positively for all 120. A big concern is whether the new box will land nicely in all pages (so checking the 20 FA's is key). Last thing we want is having to revert or skip after 115/120 have changed. -DePiep (talk) 00:43, 28 December 2016 (UTC) Step 6 will allow you to do the necessary checking before implementing anything. Doing steps 5-6 for the FAs first will take make sure you do the most important first. YBG (talk) 03:40, 28 December 2016 (UTC) Why create sandboxes for 120 new Isoboxes? Right now {{infobox uranium isotopes}} is the sandbox. Why work through sandboxes for 120 infoboxes? Their only edit needed is: when the Isobox-U is added to the article, remove |isotopes=, |isotopes comment= input from {{Infobox uranium}}. That's all (×120). Please don't spend too much time on this process. What we need is consensus that we can push this into all 120 elements. Todo: refine the federal and individual Isobox template (no big issue, also possible after publication), and assure beforehand that no articles (FA, GA) are spoiled by this extra table/infobox. That is what I am asking for. If this talk says "OK", someone will enforce an Isobox into 120+120 articles. -DePiep (talk) 09:06, 28 December 2016 (UTC) No worries. I just laid out how I would go about doing this, but it is only one way to do it. I detailed it out so that it could be understood, but the responsibility for determining what the process is lies with the person who does the heavy lifting. As it won't be me, my comments are only suggestions, to be used or ignored at will, with no heard feelings. I'm very glad you've taken the initiative on this and look forward to the result. YBG (talk) 20:27, 28 December 2016 (UTC) Is how I understood it :-). I'd like to have feedback on the resulting article from all of you, like on Talk:Uranium/sandbox. Y'know, putting an infobox halfway an article is borderline stuff, so we need a tough base (aka consensus) to do that. BTW I noticed that Double sharp has updated all the Isotope lists in the infoboxes. -DePiep (talk) 11:42, 29 December 2016 (UTC)

• New issue: maybe we should keep mentioning important isotopes in the top infobox. Say, those that are mentioned in the lede, or the top 3 by relative abundance. Now the U example is extreme (~6 notable isotopes; I'd say 4 is the max), but the oxygen infobox could mention just oxygen-16, or all three. Add the percentage?, described how? New parameter could be in "Atomic properties"? YBG -DePiep (talk) 10:13, 1 January 2017 (UTC)

  I have no objection per se. But I don't think that the mention of isotopes in the lede necessitates their mention in the infobx; there is no requirement that the infobox include all the details found in the lede. So I guess I'd generally lean toward not including any isotopes in the infobox, but I don't have a very strong opinion and will present no objection if you decide otherwise. YBG (talk) 23:32, 1 January 2017 (UTC)

  No, not because they are in the lede. But for the same reason that they are in the lede: they are important. (I am also looking for a treshold, reducing the number of them we would mention in the infobox). -DePiep (talk) 09:17, 2 January 2017 (UTC)

  Thank you, that is an important distinction. Although I'm generally an inclusionist, I would in this case tend to be a deletionist, but as I said before, I don't have a strong feeling one way or the other. But it seems to me that you have a similar sentiment that there be some sort of a threshold test for inclusion. I guess my biggest concern would be that inclusion of some important isotopes in the main infobox not undermine the case for having a separate isobox. That result would be a great loss. Thanks for your thoughtful consideration of this proposal from many different angles! All the best! YBG (talk) 16:53, 2 January 2017 (UTC)

The new Infobox <element> isotopes

This section discusses the new infobox. Pilot is {{Infobox uranium isotopes}} for U (FA)

• The Isobox. For each element, a new template {{Infobox <element> isotopes}} will be created ('Isobox' for short parlance, 120 P). By intention it has the look and feel of the {{Infobox element}} family.

It is an infobox with parameters:

{{Infobox element/isotopes
| name=
| isotopes=
| isotopes table footnote=
| relative atomic mass=
| relative atomic mass ref=
}}

The existing table 'Most stable isotopes of <element>' will be copy/pasted into the new infobox (that is, the existing |isotopes= input from {{infobox <element>}}).

• Demo {{Infobox uranium isotopes}}

Isotopes of uranium (₉₂U)

Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 232U synth 68.9 y α 228Th SF – 233U trace 1.592×105 y α 229Th SF – 234U 0.005% 2.455×105 y α 230Th SF – 235U 0.720% 7.04×108 y α 231Th SF – 236U trace 2.342×107 y α 232Th SF – 238U 99.3% 4.468×109 y α 234Th SF – β−β− 238Pu
Standard atomic weight Ar°(U)
	238.02891±0.00003 238.03±0.01 (abridged)

{{Infobox element/isotopes
| name=uranium
| isotopes=
 {{infobox element/isotopes decay2 | link=uranium-232 | mn=232 | sym=U
  ... }}<!-- one isotope, table row -->
 {{infobox element/isotopes decay3 | link=uranium-238 | mn=238 | sym=U
 | na=99.274% | hl=[[1 E17 s|4.468×10<sup>9</sup> y]]
  ... }}<!-- another isotope, table row -->
}}
|isotopes table footnote=Some footnote here
|relative atomic mass=238.02891(3)
|relative atomic mass ref=<ref>[http://www.ciaaw.org/atomic-weights.htm Standard Atomic Weights 2013].</ref>
}}

• Parameters

|name= Element name.

|isotopes= Parameter that has the table rows (the subtemplates). Same as in {{Infobox element}}

|isotopes table footnote= Footnote tied to the table. Replaces |isotopes comment=. (Used in Li, Ba, Na)

|relative atomic mass=, |relative atomic mass ref= (A_r) Added here because the "Isotopes of ..." articles add this to their lede. Can have a reference, preferably CIAAW. This value is labeled "Standard atomic weight (±) (A_r)" in the main infobox. Something needs a change?

Omitting:

Template name: the descriptive name would be like "Template:Infobox most stable isotopes of uranium". But we don't have to.

No category-colored header bars. The category is not relevant for isotopes.

No 'References' link in the bottom bar. No standard references available. References should first be in article body.

No QID (Wikidata link). There exist d:Q1369686 (isotope of uranium) and d:Q8556554 (Category:Isotopes of uranium) in wikidata, but these offer no help to the enwiki editor.

-DePiep (talk) 19:23, 27 December 2016 (UTC)

References

Changes in the proposal

• {{infobox isotopes <element>}}. Name pattern now is {{infobox <element> isotopes}}. Per comment by YBG, below.-DePiep (talk) 12:24, 29 December 2016 (UTC)
• Demo set for uranium (four pages): Talk:uranium/sandbox (article), Isotopes of uranium, {{Infobox uranium/sandbox}}, {{Infobox uranium isotopes}} (new). -DePiep (talk) 12:45, 29 December 2016 (UTC)

Comments on the new Isobox

• Just wondering whether the new template name ought to be "infobox isotope <element>" or "infobox <element> isotopes". With the former, typing "template:infobox isotope" in the search box would bring up a list of isotope infoboxes. With the latter, typing "template:infobox uranium" in the search box would bring up a list that included only {{infobox uranium}} and {{infobox uranium isotopes}} and their various subpages. Also, the latter seems IMO to be a more natural-language approach. Just a thought, I'd be fine either way. And thank you for putting the thought required to turn my ramblings into a full-blown, well-thought-out proposal. Great work! YBG (talk) 19:46, 27 December 2016 (UTC)

Probably better. btw, I always name things 'isotopes' b/c I don't want to have to remember that. -DePiep (talk) 21:35, 27 December 2016 (UTC)

Y Yes, name pattern better be {{infobox <element> isotopes}}. Will change this in a few days. -DePiep (talk) 17:02, 28 December 2016 (UTC)

 Done, "infobox isotopes <element>". Name pattern now is {{infobox <element> isotopes}}. (I've boldly edited the proposal, to root out the old name). -DePiep (talk) 12:24, 29 December 2016 (UTC)

• Any good reason that the new infobox needs to be in a template (and not just in the article)? Christian75 (talk) 19:58, 27 December 2016 (UTC)

#1. As with the element infoboxes (each of which is transcluded only once), such a set of templates is hugely easy to maintain. By WP:AWB or manually, edits are easy to check. For example, adding the wikidata link (adding |wdQID=) was a piece of cake. Problem with in-article edits using WP:REGEX is that the body text can give undesired hit-and-edits to be handled.

#2. These isotopes infoboxes are transcluded twice (in this proposal): first time the in article uranium section ==Isotopes==, second time in top of article Isotopes of uranium as a plain infobox. -DePiep (talk) 20:13, 27 December 2016 (UTC)

• A few other ideas

1. Have you given any thought to making some of the sections of the infobox collapsible? This would be one way of reducing the bulk of what is (even after splitting out the isobox) still a very large infobox.
2. Alternately, we could break out additional sections of the infobox, for example, physical properties, chemical properties. Even without isotopes, the infobox will be very very large
3. What about adding links to facilitate navigation between the infobox and the isobox? Probably not really necessary with just the isobox, but it would be very helpful if additional sections were to be broken out.

None of these is particularly pressing, but I thought I'd mention them while I was thinking about this. By the way, in order to establish a consensus, it would help to have a section for !Voting. YBG (talk) 22:30, 29 December 2016 (UTC)

re 1: (Is a separate topic, not an argument in this discussion. That said, I'll reply). We could collapse parts of the top infobox. However, in mobile view, no collapsing exists. In mobile view, any collapsible table or block is always uncollapsed. (Check the infobox aspirine, bottom data SMILES and InChI: collapsed in desktop, uncollapsed in mobile view). So we must design always an uncollapsed infobox. Collapsing is an extra, only available for some.

re 2: (Separate topic too, should not play role in this proposal). Sure, other sections could break out. Isotopes box is the lowest hanging fruit. If this works out well, more proposals could follow. But only then, after this. Another option is that we really can discuss to remove certain data rows. Say: which 10% of the rows should we remove? This is a difficult discussion, because no one wants it.

re 3: Like adding a link that leads to the Isotopes section(-infobox). I don't think that's a good idea. With other data we don't do that either. While, remember, the Infobox should present the main data that is below in the article. IOW, this way almost every data point in the infobox could have a link to a place in the article! Also, the TOC is the primary navigation place, that´s its job. BTW, the Isobox does not link to Isotopes of uranium any more. Because 1. no links allowed in an infobox title, and 2. the Isobox will be right next to the Main article: Isotopes of uranium section hatnote. DePiep (talk) 11:53, 30 December 2016 (UTC)

What an interesting topic this is. (And please don't archive it, botty!) -DePiep (talk) 00:24, 17 February 2017 (UTC)

Group 3 into -La-Ac

Implementing -La-Ac in our Periodic table article

Further to RFC consensus to use the -La-Ac table, there is an updated version of our periodic table article in my sandbox.

I could go ahead and post the thing but thought I'd list the changes here first in case there were any comments. You can also view the history of my sandbox and compare the current article (03:04 17 Jan) with the proposed article (03:05 17 Jan). (diff current versions).

Whole article
Replaced the note tags with a version that supports the citation template within the notes.

Section: Lead
Table updated (as a jpg, not an svg)

Section: Overview
Table updated (as code, not yet the template)

Section: Grouping methods
Groups subsection
Table updated (as code, not yet the template)

Section: Periodic trends
Name change to "Periodic trend and patterns" -- Sandbh (talk) 07:23, 19 January 2017 (UTC)

Electron configuration subsection

Have asked the graphics lab to updated the periodic trends table

Done (by me). Sandbh (talk) 00:01, 23 January 2017 (UTC)

New subsection added
"Linking or bridging groups" -- Sandbh (talk) 07:23, 19 January 2017 (UTC)

Section: Different periodic tables
Paragraph 5: Added new note 12 that goes "But for the existence..."

Paragraph 6: Copy edited to explain that the -La-Ac table is chosen as the most popular table. Old note 15 re gas phase and solid phase electron configurations has been removed and replaced with a simplified mention of electron configurations in the "Open questions and controversies section", "Group 3 and its elements in periods 6 and 7" subsection, paragraphs 3 and 5.

Periodic tables by different structure subsection
32-column table updated

Section: Open questions and controversies
Group 3 and its elements in periods 6 and 7 subsection
Paragraph 1: Small copy edits. The order of the Group 3 options images has been swapped.

Paragraph 2: Sentence referring to further spectroscopic work as to the electron configuration of Yb relocated here from the old paragraph 3. I removed reference to Matthias describing the placement of La under Y as a mistake. I removed reference to Lavelle's support from La under Y. I added a sentence about lanthanum's incumbency advantage.

Paragraphs 3 and 5: These are new and briefly discuss the chemical behaviour of group 3, vertical trends, and the electron configurations of the f-block, for -La-Ac and -Lu-Lr.

Paragraph 4: Added new note 19 re the expected chemical behaviour of Lr.

Footer
Updated the Periodic table (as code, not yet the template)

Pending items
Ask for an svg version of the lead jpg table

Have asked De Piep to updated the table in the "Grouping methods" section, "Metals, metalloids and nonmetals" subsection

Will ask the graphics lab to update the discovery of the elements periodic table, in the History section, First systemisation attempts subsection

Will ask Double sharp to update the eight-column table in the History section, Second version and further development table

The 32-column 8-row table in the Open questions and controversies section, Further periodic table extensions subsection, needs to be updated.

-- Sandbh (talk) 07:07, 17 January 2017 (UTC)

• Also -La -Ac in Janet's Left Step? Shows the issue of the gap (no need to hide that). -DePiep (talk) 09:27, 17 January 2017 (UTC)

  It remains -Lu-Lr in Janet's table. The idea is that it's -La-Ac may break the rectangular block patterns, but in idealized rectangular table, rectangles remain rectangular. For comparison, we display He above Ne in a regular table (because that's what chemistry dictates), but still display it above Be in Janet's (because that's what electron configs dictate). Same applies here: display Sc and Y above La in a regular table, but above Lu in Janet's.--R8R (talk) 15:07, 17 January 2017 (UTC)

• About User:Sandbh/sandbox#Group_3_constitution_variants:

These constitution variants do not belong here. This should be addressed in #Group 3 and its elements in periods 6 and 7 only (similar to issue of H and He positioning, for example). Nobody is helped at all by mixing presentation form with scientific statements. -DePiep (talk) 09:33, 17 January 2017 (UTC)

That is something I feel we should revisit once IUPAC has made a decision on Group 3. For now, the periodic table article captures the situation as it currently is. Once IUPAC make a decision, either Sc-Y-La-Ac or Sc-Y-Lu-Lr, and Sc-Y-*-** can be consigned to historical status. User:Double sharp has previously commented along the same lines. Sandbh (talk) 03:03, 18 January 2017 (UTC)

Is not about what I meant.

1. I'm not talking about 'send to history', nor 'describe as historical'. (Indeed this would be in view after IUPAC/Scerri concludes. Their 28 November, 2016 version with the new names & symbols, still uses the /*/** graphic ;-) ). I do say: describe this as three different scientific statements for group 3 composition. And so: put & keep this in the "Open questions" section. Will also have the note on what the preferred, popular option is.

2. I am talking about: do not mix up presentation form (18- or 32-column) and scientific statement. There is no argument relation between from and statement. This is what the #IUPAC on group 3 project remit explicitly says: group 3 is not does not depend on presentation form (not in both ways). So, of three-for-3 variants are not structural PT variants as is the list Left Step, ADOMAH, Benfey, ... Just as, for example, the H, He positioning does not create a new PT structure.(wrong place) So, group 3 composition should not be discussed in the '18- and 32-column' section.

3. In overview, the article should have different sections for different topics (not per se this order or ==-level):

a. PT with different structure (Left Step, ...)

b. "Group 3 and its elements in periods 6 and 7" (sub of "Open questions and controversies")

c. "Presentation forms (18- or 32-column)" (topic=title suggestion)

To be removed from a: paragraph "... 32-column form by reinstating the footnoted f-block elements into their natural position between the s- and d-blocks. Unlike the 18-column ...".

To describe this for the Reader, and in general in science, keep independent (unrelated) issues separated (unrelated). -DePiep (talk) 08:54, 18 January 2017 (UTC)

Struck and new phrase to make my point. -DePiep (talk) 16:09, 18 January 2017 (UTC)

Done. Content re group 3 constitution moved into Open questions section. Sandbh (talk) 01:32, 19 January 2017 (UTC)

Let me think some more about what to do with the 32 column form. Sandbh (talk) 01:32, 19 January 2017 (UTC)

Ok, that one's Done too. How does it all look now? Sandbh (talk) 02:24, 19 January 2017 (UTC)

Great! The TOC now says it all. Hope other ELEM regulars can agree. (Thanks Sandbh for trawling once again through my hammering remarks). -DePiep (talk) 09:25, 19 January 2017 (UTC)

Made two minor textual suggestions [1] [2]. Revert if you want to. -DePiep (talk) 09:25, 19 January 2017 (UTC)

This is all good! The 1945 thing could be worked in with a little ce and a ref. I'll be busy for the next 1½ days or so. Any volunteers? Then feel free to copy and paste my sandbox into the live article. Sandbh (talk) 12:10, 19 January 2017 (UTC)

On sourcing the Seaborg PT (~1945). Some weeks ago, you gave source here (p. 128); I can not open this page. Scerri's PT-S&S (2007) says: "[Mendeleev labeled U=240 in 1870!, and put it in group VI = Chromium]. Eventually Seaborg's discovery of the actinide series prompted a major readjustment of the PT, which included the repositioning of uranium" +footnote saying '1946' ('Uranium', p. 129). -DePiep (talk) 13:29, 19 January 2017 (UTC)

Try here http://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=522 Sandbh (talk) 21:42, 19 January 2017 (UTC)

Contrary to expectations, I find myself with some available time. I adjusted the sentence you added, and added a citation. (Seaborg's role is discussed in the previous section so I feel we don't need to go into more detail). Sandbh (talk) 23:50, 19 January 2017 (UTC)

• Sandbh, I see you have hardcoded the new PT tables into the sandbox. Shall we use like {{periodic table/sandbox}} instead, or even change the live templates right away? (I did some already...). -DePiep (talk) 09:03, 19 January 2017 (UTC)

Yes, I feel we should use templates and change the live ones. The footer one looks sweet. Sandbh (talk) 12:10, 19 January 2017 (UTC)

• Unrelated to the group 3 change, but since we are sandboxing: how about reordering section #6 into

6 Open questions and controversies
   6.1 Placement of hydrogen and helium
   6.2 Group 3 and its elements in periods 6 and 7
       6.2.1 Lanthanum and actinium
       6.2.2 Lutetium and lawrencium
       6.2.3 Lanthanides and actinides
   6.3 Groups included in the transition metals
   6.4 Elements with unknown chemical properties
   6.5 Further periodic table extensions
   6.6 Element with the highest possible atomic number
   6.7 Optimal form [or up? 6.1? DP]

Unless I am missing something, current order is random. This proposal has some logic to it (low to high; simple to complicated). -DePiep (talk) 09:33, 19 January 2017 (UTC)

I think the logic of the current order goes like this:

6.1 Elements with unknown chemical properties -- because we have categorised some elements like this in our table

6.2 Further periodic table extensions -- because once we address the 6.1 question people usually ask this next

6.3 Element with the highest possible atomic number --- and then they want to know where it might stop

6.4 Placement of hydrogen and helium --- once the big questions have been answered, we get down to the fine details and the H question might be the most common of these kinds of question

6.5 Groups included in the transition metals --- sort of goes here because the transition metals are in the main body of the table

6.6 Group 3 and its elements in periods 6 and 7 --- sort of goes here because after the main group elements and the transition metals, you are left with the Ln and An

6.7 Optimal form --- kind of the ultimate question about the periodic table

-- Sandbh (talk) 11:57, 19 January 2017 (UTC)

Not convincing for me. 6-4,-5,-6 still disflow. I prefer (my own) principles: low to high; simple to complicated. Opinion, anyone else? -DePiep (talk)

I've rearranged the section as per your suggestion. It looks quite good. Sandbh (talk) 23:23, 21 January 2017 (UTC)

Outside of the PT article

• Group 3 in the extended periodic table

See for example: Template:Extended periodic table (by Fricke, 32 columns, compact)/sandbox. Of course first we (mentally) replace the placeholder asterisk with the bottom row (turning the 32-column PT into a nice 53-column PT).

So far, the current change turns group 3: from Sc/Y/Lu/Lr/element-153 into Sc/Y/La/Ac/element-143. Does this fit within the extended PT theories? (Or element 121 be in group 3, with the gap between La-Ce, Ac-Th?) ping Double sharp. -DePiep (talk) 08:32, 19 January 2017 (UTC)

The one source I know which gives a -La-Ac extended table (Fricke) has E121 below Ac in group 3. Double sharp (talk) 10:00, 19 January 2017 (UTC)

• Local table in Transition metal. -DePiep (talk) 00:29, 22 January 2017 (UTC)

Sandbox gone live

Need to replace some code with templates, and update a few more images as per list of changes in Implementing -La-Ac in our Periodic table article subsection above, but there you go. Sandbh (talk) 00:08, 20 January 2017 (UTC)

Good. You want the top image to be svg again? It's the general advice ('svg when not a picture'). -DePiep (talk) 10:13, 20 January 2017 (UTC)

Yes, please go ahead Di Piep. Sandbh (talk) 23:17, 21 January 2017 (UTC)

This is why we do all this: PT has 15k hits per day. -DePiep (talk) 22:56, 21 January 2017 (UTC)

Translated to a year, the metrics suggest over 5,000,000 views year! Sandbh (talk) 23:17, 21 January 2017 (UTC)

Details say: low on sat/sundays, and during Christmas holyday weeks (Western world). That points to overly professional & scholarly searches. -DePiep (talk) 23:26, 21 January 2017 (UTC)

It had 5,772,939 views in 2016.... (The 233. most viewed article in 2016) - (see User:West.andrew.g/2016 Popular pages) Christian75 (talk) 08:29, 22 January 2017 (UTC)

Lanthanum and actinium infoboxes

Is there a way to get them to show their group as "3" instead of "n/a"? Even editing the field doesn't quite work. Double sharp (talk) 04:12, 22 January 2017 (UTC)

• Done in {{Infobox element/group}}, which handles the exceptions (a bit an indirect construct I agree). Is the block name still correct for the four changes La, Ac, Lu, Lr? -DePiep (talk) 12:03, 22 January 2017 (UTC)
  • You're even sharper than I am! I've corrected the block names. Thank you! Double sharp (talk) 14:25, 22 January 2017 (UTC)

Nucleosynthesis

No article on an element or its isotopes is complete without information on its nucleosynthesis—whether primordial, stellar, explosive stellar, spallation, or radioactive decay. — Preceding unsigned comment added by 70.106.231.248 (talk) 13:13, 18 January 2017 (UTC)

WikiJournal of Science promotion

The WikiJournal of Science is a start-up academic journal which aims to provide a new mechanism for ensuring the accuracy of Wikipedia's scientific content. It is part of a WikiJournal User Group that includes the flagship WikiJournal of Medicine.. Like Wiki.J.Med, it intends to bridge the academia-Wikipedia gap by encouraging contributions by non-Wikipedians, and by putting content through peer review before integrating it into Wikipedia. Since it is just starting out, it is looking for contributors in two main areas: Editors See submissions through external academic peer review Format accepted articles Promote the journal Authors Original articles on topics that don't yet have a Wikipedia page, or only a stub/start Wikipedia articles that you are willing to see through external peer review (either solo or as in a group, process analagous to GA / FA review) Image articles, based around an important medical image or summary diagram If you're interested, please come and discuss the project on the journal's talk page, or the general discussion page for the WikiJournal User group.

T.Shafee(Evo&Evo)^talk 10:39, 24 January 2017 (UTC)

+X and +Y in Isotopes of a element articles

What is meant by "+X" or "+Y" in a excitation energy column? Please see Isotopes_of_rhenium. There are also some other confusing values - without a explanation - in this article, including "non-exists" for ^168mRe and "0(100)# kev" for ^172mRe. 89.166.13.36 (talk) 22:57, 4 February 2017 (UTC)

"+X" or "+Y" probably mean that the excitation energy is not well-known, so the figure is probably a lower bound. "0(100)" probably means a notional "000 ± 100": since the "#" means it is extrapolated from trends somehow, I assume the source's extrapolation gives a silly figure of 0, but the uncertainty would make half of its possible values fall in a sensible range. I have no clue why that is listed for ^168mRe, since it certainly does exist (the link is to the paper describing its first identification). Or is the idea that no data was available in the source? I'll need to go hunt through some nuclear databases...in the meantime, here is a level scheme for ¹⁶⁸Re. Double sharp (talk) 04:19, 5 February 2017 (UTC)

And the plot thickens: ^168mRe is not in NUBASE 2012 at all! Double sharp (talk) 04:53, 5 February 2017 (UTC)

According to Wikipedia, the Lutetium has some exciting (pun intended) meta states: ^{153m1,153m2,153m3}Lu can be converted to ¹⁵³Yb without β⁺ decay. I cannot find any sources to these daughters and if I understand correctly, the IT decay should only emit some high energy gamma rays and daughter should be same nucleus at lower state. I made some edits to Isotopes_of_lutetium table. 89.166.13.36 (talk) 23:54, 5 February 2017 (UTC)

Wikipedia talk:WikiProject Chemistry#Shortcuts,_revisited

There is currently and RFC on what do do with the shortcuts used for the chemistry-related projects. Please comment. Headbomb {talk / contribs / physics / books} 16:12, 14 February 2017 (UTC)

Radiocarbon dating is an FA

I have added to our Trophy list Radiocarbon dating (edit | visual edit | history) · Article talk (edit | history) · Watch. It was promoted as FA in March 2015. Please take a look. -DePiep (talk) 22:29, 16 February 2017 (UTC)

Allow me: "Q: How did yo discover this?" — "A: I was dating!". (I got more of these. Just ask). -DePiep (talk) 23:22, 16 February 2017 (UTC)

"Did you have your Periodic Vegetables today?" (Hmm) -DePiep (talk) 22:18, 17 February 2017 (UTC)

Lighter notes on lead

• Let me note that I enjoyed the edit gulf on lead. For me, I can only count the spaces: [3], [4].
• Did you see the DAB page Lead (disambiguation)? It really says: 'If you pronounce it this way, it means ABC', etc.

When pronounced /ˈlɛd/ (rhymes with "bed")

When pronounced /ˈliːd/ (rhymes with "need")

-DePiep (talk) 01:43, 17 February 2017 (UTC)

I think it's smart. Just as the visual looks of the letters, pronunciation of what you're reading/writing is also important in reading or writing. Adding pronunciation is helpful.--R8R (talk) 06:28, 17 February 2017 (UTC)

I agree. But I'd say better not make that the main dab-page structure. Better would be like, sections: "When derived from the metal 'lead': section 1 (btw, pron is ...). When derived from the verb 'to lead': section 2 (btw pron is ..)". -DePiep (talk) 21:56, 17 February 2017 (UTC)

Unfortunately, the average native-English speaker is unlikely to know about word origins, but is quite likely to know about pronunciation. I'm not sure I like this organization, but I'm not sure what else to use. Is there anything about this at WP:DAB or WP:WikiProject Disambiguation? YBG (talk) 02:24, 18 February 2017 (UTC)

To continue over there. -DePiep (talk) 02:51, 18 February 2017 (UTC)

Supposed closure of Lead FAC

See here for the nomination and closure, and here for my response. A morning needlessly wasted. Sandbh (talk) 00:25, 28 February 2017 (UTC)

Check in and Kudos!

15 years ago I started this project with the goal of turning the Periodic table by the quality blue. I see now that it is almost all green with a lot of blue. Great work and keep it up! I no longer have time to help, but continue to be proud of what everybody who has contributed to this project has done. --mav (reviews needed) 03:19, 1 March 2017 (UTC)

Thank you so much! We still have to turn all those greens blue, though! ^_^ Double sharp (talk) 03:50, 1 March 2017 (UTC)

If only I could read German…

103rd edition (2016) of Holleman-Wiberg's Inorganic Chemistry; only 2,622 pages. Sandbh (talk) 06:06, 3 March 2017‎ (UTC)

Disputed edits in discoveries

In recent weeks, User:Squee3 has changed discovery details of several elements' infoboxes (contributions)

Today I had to revert a Template:Infobox technium change, back to the year that was plainly in the article's source. Earlier, a back-and-forth at Template:Infobox arsenic (es saying 'As far as I can tell' as a source). In both examples the infobox deviates from the article body text & sources. Last month, in Timeline_of_chemical_element_discoveries only one source was added (again deviating from Tc article source).

Seeing that the edits are badly sourced if at all, I propose that all their edits in this area are reviewed, and that Squee3 be notified that no unsourced edits are disputed a priori and so must be discussed. -DePiep (talk) 09:07, 3 March 2017 (UTC)

I think Talk:Bromine#Discovery year may shed a little light on the problem. S/he seems to be working on some kind of project in which s/he can only write down one discovery year for each element. This of course necessitates some ingenious rationalisations of history, because in this case Löwig discovered Br in 1825, Balard discovered Br in 1826 and published his discovery the same year, and Löwig published his in 1827. Surely we cannot usually know for how long people were working on something (relevant recent xkcd), so in general the date of publication is surely more important, for that is when the result was made known to the scientific community as a whole. (Obviously, the ancient elements need to be handled differently; a deliberate use or knowledge of the pure element should suffice in this case.)

There are also some cases where in retrospect, it turns out that the team which claimed to have discovered a new element was honestly mistaken (e.g. nobelium), that two people independently found an element at the same time but one had much purer samples (e.g. lutetium), and that somebody had indeed found a new element, just not the one he thought he had found (e.g. Masataka Ogawa on rhenium). Clearly, there is no way you can get all of that across in a small infobox field.

So I would think that the simplification that is necessary in rationalising history this way actually does a great disservice to interested readers, even further than the necessary one that is needed in filling the infobox field. I may have to admit on the other hand that most readers are not that interested, and that they just want a date to put in a colourful "science project" that does not involve any actual science or understanding. Still, I would argue that the "History" section ought to give the detailed account, while we should base the dates in the infobox field on published sources. Double sharp (talk) 09:55, 3 March 2017 (UTC)

when TFAs can be rerun...

Since there is now a discussion about that, a great date for rerunning periodic table would be 6 March 2019 (150th anniversary of Mendeleyev presenting his first periodic table to the Russian Chemical Society). Double sharp (talk) 09:23, 6 March 2017 (UTC)

Sure. Should be Mach 6, 1869 by Western calender (which also puts the October Revolution in November), to make 150. Not O.S. -DePiep (talk) 15:44, 6 March 2017 (UTC)

On first publication.

So Glenn Seaborg mentioned that date, unqualified wrt OS/NS calendar. From Scerri, 2007 (chapter 4 (Mendeleev, The Crucial Discovery). pp 105– and footnotes).

On backside of an unrelated letter, Feb 17, 1869 Julian calendar (OS) (the Cheese factory letter), earliest sketch of the PT as published. In today's European Georgian calendar: Mar 1, 1869. Looks like the letter was written (dated) the same day M. received & used its backside.

On that same date (stated/unsourced by Scerri): manuscript of his full PT (Scerri fig 4.2), 'horizontal groups' i.e., transposed rows/cols compared to current day 'vertical groups'. (please always add descriptive word groups or periods when using this description; a table always has something horizontal, not is horizontal).

M.'s announcement (publication) of this PT: M. had made 200 prints in Russian, sent to chemicists in Europe. "N.A. Menshutkin communicated the initial discovery to the new Russian Chemical Society on March 6". Journal publication (Scerri fig 4.3): same month, "1869".

A question about this Scerri section (Scerri 20017, p 106 in my copy, more recent isbn-13 978-0-19-530573-9):

"This first published periodic table version of Mendeleev's (figure 4.3^?) contains divisions into main and subgroups... first column ...". However, this seems to be about fig 4.4^!, a 1871 publication. That 'first column' being ~group 1 (transposed, modern). All in all this 1871 paragraph looks out of place as Scerri is describing 1869 happenings. -DePiep (talk) 10:36, 15 March 2017 (UTC)

Standard atomic weight in Wikidata

Working on relative atomic mass and CIAAW. From there, over at Wikidata I am proposing to add two Properties for elements:

d:Wikidata:Property proposal/standard atomic weight

d:Wikidata:Property proposal/conventional atomic weight

-DePiep (talk) 20:27, 7 March 2017 (UTC)

• d:Wikidata:Property proposal/relative atomic mass aeeded (The basic quantity (A_r) for moon rocks and manipulated uranium).

Also, here at enwiki I have put content into standard atomic weight (copy/pasted from relative a.m. to start with). -DePiep (talk) 23:46, 9 March 2017 (UTC)

Wikidata timely thoughts

A general note from me. What is happening now in Wikidata is serious matter (however you and I dislike it). also 'www.webchems.com' and 'www.DePiepSmartServices.com' (projected) will pull data freely from Wikidata (legally, and no source need be mentioned). Wikidata will be the source google pages pull this data from (and not enwiki any more). The problem is (for me at least): how to work with Wikidata as I am used to work with enwiki? At least for the standard atomic weights now, I could pick up and work there. -DePiep (talk) 23:46, 9 March 2017 (UTC)

Biological role of nitrogen

Biological role of nitrogen is a redirect that currently points at a non-existent section of the main Nitrogen article. I've nominated this redirect for discussion at Wikipedia:Redirects for discussion/Log/2017 March 9#Biological role of nitrogen where your comments are invited. Thryduulf (talk) 00:48, 9 March 2017 (UTC)

Reclassifying the nonmetals

This is not a formal proposal from me. I'm only requesting views from you on the alternative classification scheme set out below. There is no rush as I have some more research to do. It's therefore a slow time project. As well, R8R is engaged on getting lead to FA status; and YBG is on a wikibreak until mid-April, so I'm happy to let this sit on the bench top for quite a while.

Background

We currently colour code non-metals as polyatomic, diatomic, or noble gas.

Ever since we adopted these categories I've wondered (partly prompted by R8R) if that was the right decision, and if there was a better alternative.

This has been hard. Categorisation of nonmetals in the literature—aside from the halogens and the noble gases—is shabby. Metalloids complicate the situation. Some authors recognise such a category; others don't. The one that don't have to divvy them up between the metals or the nonmetals.

Authors usually throw up their hands and simply look at the leftover nonmetals—the ones other than the halogens and the noble gases—on a group-by-group basis. So you might have separate sections in a book on, say, hydrogen; carbon; nitrogen and phosphorus; and oxygen, sulfur and selenium. And some or all of the metalloids might get added to the applicable sections.

Otherwise there is the question of what to call these leftover nonmetals. The category names I've seen in the literature are "biogen", "CHONPS", "organogen" or "other". The first three of these categories tend to get tripped up by what to do with selenium. The last category—other nonmetals—is the "I-give-up-it's-too hard-I-need-to-get-published-so-I'll-treat-them-as-leftovers" category.

For our own classification scheme the "halogen" category is unavailable since we count astatine as a metalloid (as we should—it's either that or a post-transition metal).

Alternative scheme

In this context, an alternative scheme I've been considering has the following nonmetal categories:

Noble gas – He, Ne, Ar, Kr, Xe, Rn
Corrosive – O, F, Cl, Br, I
Intermediate – H, C, N, P, S, Se
Weak nonmetal (metalloid) – B, Si, Ge, As, Sb, Te, At

The corresponding legend looks like this:

Alkali metal

Alkaline earth metal

Lan­thanide

Actinide

Transition metal

Post-​transition metal

Weak nonmetal (metalloid)

Intermediate nonmetal

Corrosive nonmetal

Noble gas

There is no change to the colours we use; the only change is to the three category names between post-transition metal and noble gas.

Corrosive nonmetal. These are are corrosive, and highly electronegative (> 2.6) and are, or their species are, capable of acting as relatively strong oxidising agents. Here are some examples from the literature as to other similarities between oxygen and fluorine, oxygen and the halogens, and oxygen and chlorine:

• "Fluorine tends to bring out the highest valence of the element with which it combines. In this its shows a strong resemblance to oxygen. In combination with metals, oxygen appears to be the best for the highest valences, e.g. OsO₄ and KMnO₄, but fluorine appears best if the highest valence is relatively low, e.g. for CoF₃, CuF₃, AgF₂, TbF₄, and BrF₅. With non-metals the difference between oxygen and fluorine is less apparent." (Phillips & Williams 1965, p. 446)
• "…oxygen, like fluorine, forms strong covalent bonds, and there are a number of similarities between covalent oxides and fluorides." (Emeléus & Sharpe 1973, p. 318)
• "Simple anionic chemistry is limited to oxygen and the halogens, although polyanions and polycations can be formed by many [nonmetals]." (Cox 2004, p. 145)
• "Chlorination reactions have many similarities to oxidation reactions. They tend not to be limited to thermodynamic equilibrium and often go to complete chlorination. The reactions are often highly exothermic. Chlorine, like oxygen, forms flammable mixtures with organic compounds." (Kent 2010, p. 104)

Intermediate nonmetal. The more temperate nature of the intermediate nonmetals is relatively self-evident, situated as they are between the corrosive nonmetals and the weak nonmetals. This is so-called "other nonmetal" territory. There is a magic thread (my name for it) that binds the intermediate nonmetals, and it goes like this: H → C → P → N → S → Se:

• Chemical similarities between H and C were discussed by Cronyn (2003) in the Journal of Chemical Education. They include proximity in ionization energies, electron affinities and electronegativity values; half-filled valence shells; and correlations between the chemistry of H–H and C–H bonds.
• C and P represent an example of a less-well known diagonal relationship, especially in organic chemistry. Spectacular evidence of this relationship was provided in 1987 with the synthesis of a ferrocene-like molecule in which six of the C atoms were replaced by P atoms (Rayner-Canham 2011, p. 126). Further illustrating the theme is the extraordinary similarity between low coordinate P compounds and unsaturated C compounds, and related research into organophosphorus chemistry (Dillon, Mathey & Nixon 1998).
• P and N are in the same group. Although N and its oxides are gases whereas P and its oxides are solids, the two elements "show many similarities in their compounds" (Malati 1999, p. 83). Despite these similarities "the chemistries of nitrogen and phosphorus are very different" (Wiberg 2001, p. 686). However P and N form an extensive series of phosphorus-nitrogen compounds having chain, ring and cage structures; and the P-N repeat unit in these structures bears a strong resemblance to the S-N repeat unit found in the wide range of sulfur-nitrogen compounds (Roy et al. 1994, p. 345) discussed next.
• N and S have a less-well known diagonal relationship, manifested in like charge densities and electronegativities (the latter are identical if only the p electrons are counted; see Hinze and Jaffe 1962) especially when S is bonded to an electron-withdrawing group. They are able to form an extensive series of seemingly interchangeable sulfur nitrides, the most famous of which, polymeric sulfur nitride, is metallic, and a superconductor below 0.26 K. The aromatic nature of the S₃N₂²⁺ ion, in particular, serves as an exemplar of the similarity of electronic energies between the two nonmetals (Rayner-Canham 2011, p. 126).
• S and Se are in the same group: "As in the case of the halogens, the chemical similarities, at least for sulfur and selenium, are abundantly obvious" (Scerri 2007, p. 49).

Weak nonmetal (metalloid). Some authors count metalloids as nonmetals with weakly nonmetallic properties rather than having a discrete metalloid category, and that's the approach I've taken here. For a recent example see Cox (2004, pp. 26–27), who treats B, Si, Ge, As, Sb, Te and At as nonmetals, but notes that Si, Ge, As, Sb, Se and Te are sometimes called metalloids.

Precedents, approach, and features

In terms of precedents, the literature certainly refers to (a) O, F, Cl, Br, and I as having corrosive qualities; and (b) to the weakly nonmetallic chemistry of the metalloids. As far as I can see nobody has ever referred to an intermediate nonmetals category but then the literature is a terminological wasteland when it comes to a collective name for this part of the periodic table. Just about anything would be better than "other nonmetal".

I had to apply some violence and abstraction of detail to the alternative scheme in order to keep it simple. So there may arguably be some discontinuities and boundary overlaps. For example, counting iodine in the same league as O, F, Cl and Br may raise an eyebrow. Then again, iodine is corrosive, has a pretty decent electronegativity (2.66), and its periodate ion is a formidable oxidising agent (stronger than the perchlorate ion, for example); even the iodate ion is a stronger oxidant than elemental bromine. And pragmatically speaking it makes more sense to keep iodine with its lighter halogen congeners. As another example, nitrogen has a high electronegativity of 3.04 but all of its chemistry is essentially covalent, and the average oxidising power of nitrogen and its species, in aqueous solution, is less than that of both iodine and of sulfur.

On the question of discontinuities and boundary overlaps I turn to Jones (2010, pp. 170–171): "Though classification is an essential feature of all branches of science, there are always hard cases at the boundaries. The boundary of a class is rarely sharp…Scientists should not lose sleep over the hard cases. As long as a classification system is beneficial to economy of description, to structuring knowledge and to our understanding, and hard cases constitute a small minority, then keep it. If the system becomes less than useful, then scrap it and replace it with a system based on different shared characteristics." I feel that the similarities within each of the categories of weak metal (metalloid), intermediate nonmetal, and corrosive nonmetal outweigh their differences, and blurry edges, sufficiently to establish them as discrete divisions.

The alternative scheme is better than what we have now because it's easier to get your head around, the new category names are more natural, and the new categories themselves fall into place quite naturally.

It maintains a good job of showing the progression in metallic to nonmetallic character as you go from left to right across the periodic table. And it facilitates a symmetry that is more rewarding than the contrast between metals and nonmetals, or between the alkali metals and the group 17 nonmetals, as shown in the following side-by-side match-up:

"Reactive metals" ^ Groups 1–3, Ln, An			Corrosive nonmetals O, F, Cl, Br, I
Transition metals (the "mundane" ones) Most of 'em			Intermediate nonmetals H, C, N, P, S, Se
Post-transition metals Ga, Bi etc			Weak nonmetals (metalloids) B, Si, Ge, As, Sb, Te, At
Noble metals ^ Ru, Rh, Pd, Ag, Os, Ir, Pt, Au			Noble gases He, Ne, Ar, Kr, Xe, Rn

^  I am not proposing that we have colour categories for reactive metals, and noble metals. The current colour categories for metals (alkali, alkaline earth, transition, lanthanide, actinide, post-transition) are fine.

There are references in the literature to this pattern. For example:

• "Between Groups I and VII there are gradations from active metals (Col. I) to less active metals to moderately active nonmetals to volatile nonmetals (halogens Col. VII)." (Perlman 1970, p. 439)
• "A period represents a stepwise change from elements strongly metallic to weakly metallic to weakly nonmetallic to strongly nonmetallic, and then, at the end, to an abrupt cessation of almost all chemical properties." (Booth & Bloom 1972, p. 426)
• "By the end of 8th grade, students should know that…there are groups of elements that have similar properties, including highly reactive metals, less reactive metals, highly reactive nonmetals (such as chlorine, fluorine and oxygen) and some almost completely unreactive gases (such as helium and neon)." (AAAS 1994, p. 78)
• Between the "virulent and violent" metals on the left of the periodic table, and the "calm and contented" metals to the right are the transition metals, which form "a transitional bridge between the two" extremes. (Atkins 2001, pp. 24–25)
• "Describe how groups of elements can be classified…including…highly reactive nonmetals, less reactive nonmetals, and some almost completely nonreactive gases." (Padilla, Cyr & Miaoulis 2005, p. 27)

Overall, I find the combination of:

• symmetry (as in the four complimentary metal-nonmetal categories)^† and asymmetry (many metals/few nonmetals);
• the natural fit of the intermediate nonmetals between the weak nonmetals and the corrosive nonmetals;
• the thread that links the nonmetals in this category (i.e. the intermediate nonmetals); and
• the balanced 5-6-6-6 distribution of the nonmetals across their four categories

to be especially pleasing.

† The fact that there are 4 + 4 = 8 symmetry components is cool, too.

The wisdom of YBG

YBG suggested that any new categorisation scheme should be:

• clear—"The criterion for division should be easily explained";
• unambiguous—"It should be relatively obvious which category each element fits into"; and
• meaningful—"The categories should have significance more than just dividing for the sake of dividing. There should be enough within-group similarity and enough between-group dissimilarity so that each group could be the subject of a separate encyclopaedia article."

Clear. In this case, the criteria for division go something like the following:

• The noble gas category is self-evident (so to speak).
• The corrosive nonmetals are, well, corrosive.
• The weak metal (metalloid) category corresponds to the elements commonly recognised as metalloids. Astatine, which is included here, is irregularly recognised as a metalloid but we decided quite a while go to recognise it a metalloid. It has since been predicted to have the band structure of a full-blown metal.
• The remaining nonmetals, which are neither corrosive nor weak (metalloid), are the intermediate ones.

This is so easy it almost explains itself.

Unambiguous. It is relatively obvious which category each element fits into.

Meaningful. As discussed earlier in this section, the resulting categories have enough internal similarity, and between category dissimilarity, to make them meaningful. We already have separate articles for noble gases and metalloids; I'd be inclined to have separate sections for intermediate nonmetals and corrosive nonmetals in the nonmetal article, as we do now for the polyatomic nonmetals and diatomic nonmetals.

References

• AAAS (American Association for the Advancement of Science) 1994, Benchmarks for science literacy, Oxford University Press, New York
• Atkins PA 2001, The periodic kingdom: A journey into the land of the chemical elements, Phoenix, London
• Booth VH & Bloom ML 1972, Physical science: a study of matter and energy, Macmillan, New York
• Cox PA 2004, Inorganic chemistry, 2nd ed., Bios Scientific Publishers, London
• Cronyn MW 2003, "The proper place for hydrogen in the periodic table", Journal of Chemical Education, vol. 80, no. 8, pp. 947–950, doi:10.1021/ed080p947
• Dillon KB, Mathey F & Nixon JF 1998, Phosphorus: The carbon copy: From organophosphorus to phospha-organic chemistry, John Wiley & Sons, Chichester
• Emeléus HJ & Sharpe AG 1973, Modern aspects of inorganic chemistry, 4th ed., Routledge & Kegan Paul, London
• Jones BW 2010, Pluto: Sentinel of the outer Solar System, Cambridge University Press, Cambridge
• Kent JA 2007, Kent and Riegel's Handbook of industrial chemistry and biotechnology, 11th ed., vol. 1, Spring Science + Business Media, New York
• Malati MA 1999, Experimental inorganic/physical chemistry: An investigative, integrated approach to practical project work, Woodhead Publishing, Oxford
• Padilla MJ, Cyr M, Miaoulis I 2005, Science explorer (Indiana Grade 6), teachers's edition, Prentice Hall, Upper Saddle River, New Jersey
• Perlman JS 1970, The atom and the universe, Wadsworth Publishing, Belmont, California
• Phillips CSG & Williams RJP 1965, Inorganic chemistry, vol. 1, Principles and non-metals, Clarendon Press, Oxford
• Rayner-Canham G 2011, "Isodiagonality", Foundations of Chemistry, vol. 13, pp. 121–129, doi:10.1007/s10698-011-9108-y
• Roy AK, Burns GT, Grigora S & Lie GC 1994, "Poly(alkyl/aryloxothiazenes), [N=S(O)R]_n : New direction in inorganic polymers", in P Wisian-Neilson, HR Alcock & KJ Wynne KJ (eds), Inorganic and organometallic polymers II: advanced materials and intermediates, American Chemical Society, Washington DC, pp. 344–357, doi:10.1021/bk-1994-0572.ch026
• Scerri E 2007, The Periodic Table: Its story and its significance, Oxford University Press, Oxford
• Wiberg N 2001, Inorganic chemistry, Academic Press, Berlin
• Wisian-Neilson P, Alcock HR, Wynne KJ (eds) 1994, Inorganic and organometallic polymers II: advanced materials and intermediates, American Chemical Society, Washington DC

Comments

Some first responses. Added bullets to allow for subthreading. -DePiep (talk) 12:07, 12 March 2017 (UTC)

• Interwiki RfC? Is it possible to enlarge support for our enwiki categorisation by making this an interwiki RfC? Our 2013 changes did not pick up well even in large wikis like de:, zh:, ru:, fr: (halfway only); ja: did. Note: checking the At category is enough, I can't blame any wiki for not using the poly-/di-atomic category names. -DePiep (talk) 12:07, 12 March 2017 (UTC)
  • And guess who made it stick for ja:! ^_^
  • BTW, there is some regional variation as well: in Japanese アルカリ土類金属 is a direct calque of "alkaline earth metal", but it only refers to Ca, Sr, Ba, and Ra (not Be or Mg). Double sharp (talk) 13:20, 12 March 2017 (UTC)

I'd like to contain the discussion to our own project, for now. Kudos to Double sharp san. Sandbh (talk) 23:42, 12 March 2017 (UTC)

Changing name from "metalloids" into "weak nonmetals"

• Changing name from "metalloids" into "weak nonmetals". This is a surprise, and I'm not yet convinced. I didn't know there is a problem with 'metalloids'. First, the new name introduces a relative term in "weak": weak compared to others I must understand. And these others are: nonmetals (a de-classifying name by itself). So I must understand that there are elements that are stronger nonmetals, that are opposite of metals altogether. Then, seeing their position next to metals in the periodic table, if they are 'weak nonmetals', are they almost 'strong metals'? Or almost 'weak metals'? This is not playing, this is what words do. -DePiep (talk) 12:07, 12 March 2017 (UTC)

This is truly excellent and thoughtful feedback, thank you DiPiep.

To clarify, I am proposing to change the category name from "metalloid" into "weak nonmetal (metalloid)". I will discuss a problem with the term "metalloid" a little later in my response but for now it has its uses, which is partly why I am proposing to retain this word in the new category name. Yes, I agree, if you see the expression "weak nonmetal (metalloid)" it suggests there are stronger nonmetals, which is indeed the case.

If you see that they are positioned next to metals in the periodic table, and this prompts you to wonder if they are almost weak metals or almost strong metals then this is a good thing. The name piques curiosity, rather than bewilderment. I did not know what a metalloid was the first time I saw that word but I sure knew what metals and nonmetals were. The proposed category name is more informative than our other category names, which rely on some level of familiarity to be able to work out what they mean.

The scenario of wondering if a weak nonmetal would almost be a strong metal seems unlikely. Things in general get named for their dominant character rather than any subsidiary character, don't they? Some 'strong' transition metals are capable of forming oxyanions, which is nonmetal-like behaviour, but nobody calls these elements weak nonmetals. Crudely put, if an element was one-third nonmetallic (i.e. weakly non metallic) and two-thirds metallic (i.e. almost strongly metallic) it would be classified as a metal rather than a nonmetal. An analogy can be drawn with water that is weakly acidic (pH 6). This does not mean the water is almost strongly alkaline (pH 12). It means the water is almost weakly alkaline (pH 8).

I am sorry to say that one cannot work this out from the name "post-transition metal". If we had used something more descriptive like "poor metal" that would likely have answered the general reader's question. They would see that weak nonmetal was next to poor metal. But we decided to use "post transition metal", which is fine for the more technical reader. Alas, I feel that I should only work with the metal category names that we have. Sandbh (talk) 04:32, 20 March 2017 (UTC)

You raise very good points here, as always.

Yet I have a bit of an objection to this. Is it not the case that all of these descriptive terms need some knowledge of chemistry to understand? You can't understand "alkali metal" or "halogen" without knowing what an alkali or a salt is (in the latter case you also need to have a little knowledge of Ancient Greek, namely ἅλς "salt, sea"). You need some of this knowledge to get anywhere, and often you only get it retrospectively. If the name of the category does not suffice to tell us how Au or Te behaves, then maybe we should look more at the chemistry of their groups as a whole. Double sharp (talk) 04:16, 21 March 2017 (UTC)

I may have misunderstood the basis for your concern but will plough on anyway.

Largely I would say yes you do need some knowledge of chemistry to know what these terms mean. Alkali metals and alkaline earth metals may be somewhat of an exception. I can recall a high school science demonstration of calcium skipping about on the surface of water so that may have given me some idea of the nature of an alkali or alkaline earth metal. I can't remember when I learnt what "alkaline" meant but it may have been when I was introduced to the idea of acids and bases and phenolphthalein—and that was only in general science. And I'm pretty sure I knew by them what quicklime was and its causticity, although I can't remember if I would have recognised this as being due to its alkaline nature. I can't remember if I saw what happened when a few drops of iodine were added to powdered aluminium. Nor can I remember when I was taught about the contrast between sodium and chlorine. And I don't know if high school chemistry these days includes real experiments designed to show the properties of such reactive metals and nonmetals.

There are some category names that I would recognise without needing a background in chemistry. Base metals, precious metals or coinage metals. Maybe even refractory metals. Ferromagnetic metals. Gaseous nonmetals. Crystallogens perhaps.

It's good thing to have simpler descriptive category names, is it not? Sandbh (talk) 10:12, 21 March 2017 (UTC)

It is a good thing, but there are always some prerequisites. And we shouldn't forget that some of the names are misleading, even though they are intuitively obvious. Pb may be a crystallogen, but it does not even have a diamond cubic allotrope, and while Sn does have one it's not really that attractive to look at. Some of these have artificial breaks: Re is a precious metal (of sorts) but Tc is not, because no one wants to have radioactive things (never mind that Tc has a long half-life and decays to clean stability, eliminating most of the problems with things like Pu and Cm which have comparable half-lives).

Well, yes, there are always some prerequisites; equally, category names are labels of convenience not labels of absolute truth, are they not?

There are several other category names that fall short under pressure. The alkaline earth metals category is a pretty good label for most of the group II metals but wobbles a bit in accommodating beryllium and its amphoteric oxide, and its capacity to form beryllates. (What is an amphoteric element doing hiding among a bunch of supposedly alkaline metals? Hoping no one will notice? ^_^). Pnictogens is an IUAPC approved name for group 15 but has zero intrinsic relevance to anything after nitrogen. Much of the chemistry of the early actinides is quite different from that of actinium. The crystallogen example is interesting. C, Si and Ge form diamond cubic allotropes at room conditions; tin only does so at low temperatures and the result is an amorphous grey power unless special care is taken to prepare it in its crystalline form (which looks metallic). A diamond cubic form of lead has not so far been prepared but there has been speculation that this might be possible under the right conditions.

Labels of convenience, as such, don't necessarily care or need to worry about artificial breaks. Sandbh (talk) 04:47, 22 March 2017 (UTC)

And it seems to me that "polyatomic" and "diatomic" have fewer prerequisites, as they do not require us to get an idea about what could be intermediate about nonmetals (which means learning the chemistries of many of these elements, which are fantastically complicated, so we don't tend to go past the vital C and H in high school): they just require us to learn a few simple terms. Later we can marvel about how these two are correlated with other important properties as well. Double sharp (talk) 14:37, 21 March 2017 (UTC)

Maybe "polyatomic" and "diatomic" require as much pre-knowledge as intermediate nonmetals i.e. you need to at least know what polyatomic means, and for intermediate you need to know they are neither as extreme as corrosive nonmetals (like Cl) nor as weak as weak nonmetals (like Si). If you happen to have a wikipedia table in front of you with the proposed new colour categories you will at least be able to appreciate straight away the relevance of the intermediate label (just like the transition metals are transitional). I don't think there is much between the two schemes in this sense, nor is there is much need to, at first, go past C and H in either of them. Sandbh (talk) 04:47, 22 March 2017 (UTC)

re you do need some knowledge of chemistry to know what these terms mean. Alkali metals .... Is true, but is not the primary issue in categorising. Category name and meaning is secondary, and that's what links are for. Primary is: group together what belongs together, and do not include stuff that does not include there. Just give the group a unique color and name, that's enough. The name can be as fancy or invented, no intrinsic meaning required, no prior knowledge for the reader required. Exactly what the grouping criteria is, should be described in the namelink or in an overview article. OTOH, a name should not be misleading by ignoring existing prior knowledge (is why we cannot reuse and redefine 'rare earth metals' for lanthanides). In this case, I think that 'metalliods' (and 'de:halbmetalle') are fine, unloaded words. Once we would use '.. nonmetal' somehow, it can not be made to mean 'but not really a nonmetal' any more. -DePiep (talk) 08:57, 22 March 2017 (UTC)

Hmm, I don't like the term 'halbmetalle' or its English relation 'semi-metal' given confusion with the physics-based terms half-metal, and 'semimetal'. In the latter case only carbon, arsenic, antimony and bismuth are semi-metals yet few would regard carbon and bismuth as metalloids.

I no longer like the term 'metalloid' (but I acknowledge it is still used in the literature). It means 'resembling a metal' but since metalloids generally behave at least chemically like nonmetals, the term 'metalloid' tells less than half the story. Even physically, metalloids mostly act like semiconductors and are brittle, which are properties associated with nonmetals, so although they have the appearance of faux-metals, the 'metalloid' nomenclature is rather misleading.

I prefer the term 'weak nonmetal (metalloid)' as it captures the best of both worlds, without misleading anyone, and it does not involve a change of meaning.

I'm sorry to say what I'm about to say next. Considering how important classes are in chemistry, one would think that IUPAC would have gotten its terminological and conceptual house in order but no, it hasn't, so we're stuck with the mess that is metalloids and semimetals, while the physicists happily apply these words to their own, much better defined, physics-based uses. Poor show, IUPAC. Sandbh (talk) 12:28, 22 March 2017 (UTC)

I used 'halbmetalle' only as an illustration of a not-misguiding word, as is 'metalloid' (or so I thought). If there is no descriptive available spot on, and if 'halfmetal' or 'metalloid' etc. are mainly wrong (I doubt), I'd prefer a new, unloaded wording. Definitely not 'semi-conductor' for that is only one property. I don't think the combination wording 'weak nonmetal (metalloid)' will stick; others will pick one ~randomly, so we'll be introducing a future confusion, also since we (enwiki) cannot control their definitions when used off-site. "Category Q", "MNM", "HM"? (kept as unspecified lettercodes).

Sure this is a task waiting for that IUPAC initiative. After groups, periods and blocks I think categories (we needed to invent this word too) are the 4th graphic structural visible in the periodic table (the rest is text in element cells). BTW, we could filter & funnel our threads into some Categorisation of elements by metallic-nonmetallic characteristics. -DePiep (talk) 16:59, 22 March 2017 (UTC)

Another issue with the proposed name is, that it claims the metalloids as 'nonmetals'. Sure there will be some arguments for this in literature, but to me it is a surprise major change. Our 192 sources on metalloids did not float what must be such an obvious characteristic. And, seeing the property comparing overviews on multiple characteristics, also does not push them into nonmetals (in some properties they are plain metals even). So naming them 'nonmetal' is a change of concept difficult to get. In other languages they are still called de:halbmetalle. Some naming history is nicely described in metalloid (the lede for starters). All in all, I gather that it is bad practice to use a single characteristic description for the overall category name. -DePiep (talk) 12:07, 12 March 2017 (UTC)

This is why I am proposing to change the name to "weak nonmetal (metalloid)". Our lists of metalloids article was only a list. It's purpose was to show which elements were classified as metalloids in the literature. This explains why it does not say anything about metalloid chemistry.

At this point I feel it would indeed be helpful to summarise more of the state of the literature.

• There is consensus that some elements, in the vicinity of a line running roughly through boron to astatine, can be tricky to classify as either metals or nonmetals.

• Some authors classify these elements as metalloids. Others make a call and classify each of these elements, on a case-by-case basis, as either a nonmetal or a metal. In this scenario, there is consensus that boron, silicon and tellurium are nonmetals. Germanium is sometimes classified as a metal and sometimes as a nonmetal; the same goes for antimony and polonium. In light of astatine's status as a halogen, its unimportance, and seeming uncertainty as to its properties, the lowest common denominator consensus is to assume that it's a nonmetal.

• Each of these classification decisions are open to challenge. This rarely occurs, as long as the rest of what the author writes is not completely inconsistent with their original classification decision (and presuming this decision was not blatantly erroneous on the first place).

• There is consensus in the literature that metalloids have properties that are intermediate between those of metals and nonmetals or properties or a mix of metallic and nonmetallic properties. There is consensus in the literature that metalloids look like metals and are semiconductors. (The fact that arsenic and antimony are not semiconductors in their most stable forms is a common oversight).

• Much of the literature stops at this point. Any further discussion of elements that are considered to be metalloids generally occurs only in the parts of texts giving the general descriptive chemistry of the elements in each p block group.

• There is consensus in the more considered literature that metalloids or nonmetals in the vicinity of the dividing line between metals and nonmetals generally behave chemically like weak nonmetals (and that metals in the same vicinity generally behave chemically as weak metals e.g. Tl, Pb, Bi).

In summary, the proposed term "weak metal (metalloid)" captures the complexity of the situation with a high degree of consensus—much higher than we have now with "metalloid". By itself the term "metalloid" is misleading, since it means 'resembling a metal', which is less than half the story. But the term weak nonmetal (metalloid) expresses the nature of these elements much more comprehensively, and accurately.

As to our own content, the metalloid article, the properties of metals, metalloids and nonmetals article, and the origin and use of the term metalloid article each note that the overall chemical behaviour of metalloids is nonmetallic. Yes, some of their properties are halfway between metals and nonmetals, but none of these properties are beyond the scope of what you could reasonably expect to find in nonmetals on the borderline between metals and nonmetals. And most of the metallic properties of metalloids are physical properties, and physical properties are trumped by overall chemical behaviour. Sandbh (talk) 04:32, 20 March 2017 (UTC)

I am not sure that they should be trumped so completely though, especially in such a borderline region when no one's arguing over which elements are in the group. If you look at any p-block group going down, you will start with mostly nonmetallic character (notwithstanding that boron is an "honorary metal atom" and vice versa), and you will gain more and more further down. If we look at group 16, for instance, O and S are insulators, Se and Te are semiconductors, and Po is a metal; and while chemistry lags behind a little, we do see some emerge, as Se is not attacked by dilute HCl, while Te dissolves slowly and Po dissolves enthusiastically to give pink Po^II and self-oxidises to yellow Po^IV. And tellurium even looks like a metal: there's a reason why Müller, who discovered Te, called it metallum problematicum.

I don't think it's a far stretch to say that the metalloids look like metals but act like nonmetals, although of course we have to take this with a pinch of salt (I suppose that needs to be Na₂Te for this post), but in contrast to humans where beauty is no guarantee of moral character, the shiny lustre does say something about an element's physical properties, which we shouldn't neglect. There's even fuzziness on the other side; Ge dissolves slowly in hot concentrated H₂SO₄ and HNO₃, proving that some of the metallic character that we had expected is there, if muted by the d-block contraction. But even Sn is amphoteric, as is shown by the following reaction:

Sn + 2 KOH + 4 H₂O → K₂[Sn(OH)₆] + 2H₂

It also has a clearly nonmetallic allotrope to boot, while Si and Ge transform to metallic tetragonal β allotropes like Sn if you just subject them to pressure along the c-axis (~200 kbar for Si, ~120 kbar for Ge). Even the SnX₄ are tetrahedral volatile solids and liquids and the obvious comparison is with the tetrahalides of Si and Ge. So tin appears to be fair game for being a "weak nonmetal" as well in this sense, which is funny because if you go one step to the right(!) you obtain a more clearly ionic compound in SbF₃ and even a clearly intermediate SbI₃! Furthermore, looking at group 15, As, Sb, and Bi have very similar electronegativities, so that cannot be the only guideline for grouping them as metals, nonmetals, or metalloids; the difference is structures is more reflective of how the octahedral gaps in the hcp iodine lattice are filled by each of these elements, and only Bi is large enough to fill them symmetrically.

Of course, we can wave away the question of why such elements are separated by appealing to the literature, but this is science: if the literature says something, we should critically examine it to figure out why something is being said.

And even with clear if intermediate nonmetals like phosphorus, even the halides are getting close to the ionic-covalent divide: PCl₅ is ionic [PCl₄]⁺[PCl₆]⁻ in the crystalline phase and covalent in the gas phase, and PBr₅ (which is [PBr₄]⁺[Br]⁻) outright decomposes in the gas phase. Indeed, phosphorus is so common an element that I remember being told this one in high school. ^_^ The solvent itself also influences the choice between ionicity and covalence, and even tweaking the substituents can lead to massive changes: PhPCl₄ is molecular while MePCl₄ is ionic. There is metallic character even here, and focusing on the nonmetallicity fails to show it clearly.

But the main point is that "metalloids" is way more common in the literature than "weak nonmetals". The "metal" tells you that at face value, that is what they look like: the "-oid" suggests that appearances can be deceiving. What is there more to ask for a term? Double sharp (talk) 14:59, 22 March 2017 (UTC)

Leftover nonmetals categorising

• Leftover nonmetals categorising. This is more problematic, in that it does not succeed in making a (YBG-)convincing subclassification. It could be an improvement in that at least one class (into corrosion) has a wiki article compared to zero for both of todays categories. The magic thread Sandbh points out (I'd call a magic chain) links the elements by pairs only. This breaks an other ground rule for good classification: class elements should all be strongly tied within the category, and badly tied to outside the category. The chain does not do this (no. 3 is not tied to no. 1).

Maybe this is happening: if sub-categorisation of the leftover nonmetals is that difficult, absent or sought after, there probably is no subcategorisation. Keep them one category? Of course, all descriptions and notes made in the reasoning still are valid, and should have a place in the article leftover nonmetals (working title). -DePiep (talk) 12:07, 12 March 2017 (UTC)

Looking at all the elements that are not metals, there are three categories that almost populate themselves; noble gas; corrosive nonmetal; and weak nonmetal (metalloid). We know that the corrosive nonmetals are strong nonmetals and that the weak nonmetals (metalloids) are weak nonmetals. The remaining nonmetals are neither as strongly nonmetallic as the corrosive nonmetals nor as weakly nonmetallic as the weak nonmetals. They are in the nonmetal goldilocks zone—not too chemically hot, not too chemically weak. Effectively, they are intermediate nonmetals.

The magic chain of the intermediate nonmetals is not the primary thing that links them. What links them is their temperate or moderate nature, compared to the corrosive nonmetals and the weak nonmetals. Sure, rather than reading the chain as H → C → P → N → S → Se, you could read it as H → C; C → P; P → N; N → S; S → Se. I think this is cutting off your nose to spite your face. Even across groups 1 to 18, only the elements in groups 1, 3, 17 and 18 are strongly tied together, and group 1 becomes a little wobbly if it includes H. There are more groups that are not tied together strongly than there are groups that are tied together strongly. But I don't think this matters since organising the groups according to their valence states is what revealed the deeper relationships among the elements in the first place, including the diagonal relationships and patterns which become particularly prominent in the p block.

Yes, it is hard to subcategorise the leftover nonmetals i.e. those that are not noble, corrosive, nor weak (metalloid). There are only a few names that have been given to them in the literature and none of these are widely used. That does not mean we necessarily need to adopt an unfortunate category name like other nonmetal, when—consistent with the literature—I like to think that there are more generic, helpful, descriptive and preferably plain English words that we could try. I may be deluded though given how hard it seems to be to come up with something better than "other".

The proposed scheme fine-tunes our nonmetal categories in way that is more consistent with the literature, and retains and enhances the work of the founders of the Wikipedia periodic table colour categories. (The first scheme, from February 2002, was based on the LANL table, and the Environmental Chemistry table, here.) Sandbh (talk) 04:32, 20 March 2017 (UTC)

The trouble is that I do not see why the thread should stop there. If it can go from S to Se, why not from Se to Te? They're not all that different chemically. Simply put, there does not seem to be a very clear demarcation as to why the thread should contain some elements and not the others, that isn't rationalised from already having selected which elements to exclude from the other categories and put in the thread. Double sharp (talk) 04:16, 21 March 2017 (UTC)

The thread can be traced back as far as H → Li → Mg → Be → Al → B → Si → C → etc. It alternates between diagonal links (which are often forgotten) and vertical links, and since going onto Te will result in two vertical links, S is a natural place to stop. (It did not occur to me at the time to keep going onto Te, since S was an intermediate nonmetal and Te was a weak nonmetal). The fact that there is this thread that runs through all of the intermediate nonmetals wasn't something I realised until later. The natural part—like falling off a log when compared to the poly/di-atomic marathon—was dividing the nonmetals into the corrosive nonmetals (they speak for themselves) and the weakly nonmetallic metalloids (they speak for themselves, too). All that was left after that were the goldilocks nonmetals most of which have been labeled with the "it's-too-hard-to-work-out-what-to-call-them" category name of "other nonmetals". I didn't realise that they happened to be linked by diagonal and vertical links until I thought about what else they had in common, aside from being intermediate nonmetals. If I have made too much of a song and dance about the magic thread, I can only reiterate that the main game is about the contrast between the weak nonmetals (metalloids) and the corrosive nonmetals, and the remaining bystander or sandwich nonmetals (relatively speaking). Sandbh (talk) 13:13, 21 March 2017 (UTC)

Okay, but surely not all the diagonal links are relevant: surely no one thinks that fluorine has anything to do with argon. I don't think the diagonal links are often forgotten: the ones between Li and Mg, as well as Be and Al, are really quite well-known. What is forgotten is that the analogy may be pushed further (though there are limits; comparing Ce and Pa is rather nonsensical).

More to the point, the trouble I find is that the distinction is very fuzzy, and there is nothing like the precipitous drop in metallic behaviour that occurs when you cross past group 11 (there is another drop between very strong metals and milldy strong metals past group 3 and the Ln and An). There is a reason I raised selenium and tellurium: we split them into two separate categories, even though they are very similar chemically and are in fact very often found together: we shouldn't forget that selenium was named after the moon because it resembled tellurium, which was discovered earlier and was named after the Earth! They even form a continuous range of solid-state solutions in which Se and Te atoms alternate in the helical chains (since hexagonal Se resembles the main modification of Te in its structure).

So why do we put selenium apart from tellurium in the first place? Because Se has a number of properties that are somewhat uncharacteristic of a nonmetal which are only brought to maturity in the next member of the group. But already Se shows an advance on S in incipient metallic properties, so that if one is willing to call S–Se a valid link, then disallowing Se–Te immediately after that seems to show symmetry being taken too far (after all, S forms S₈ molecules while Se and Te form long chains). S–Se–Te is quite a good triad for this "no man's land" between clearly metallic and clearly nonmetallic territory and it does not sit well with me to get rid of it for reasons like this. It is fine if we are applying some artificial sharpness in our categorisation by going for a hard line based on how many atoms happen to be in a molecule of the pure element (never mind that S and I seem a little out of place), but with fuzzier categories like this I am slightly more ill at ease. Double sharp (talk) 14:09, 21 March 2017 (UTC)

Indeed, there is no diagonal link between fluorine and argon and I did not allude to this. In my experience, the diagonal links are ignored---certainly in high school where the focus is on vertical similarities. Maybe things have changed since I went to HS; I tend to doubt it.

On the fuzziness of the proposed categories, and I hope I am not belabouring things, I did not make the distinction between (a) corrosive nonmetals and (b) metalloids, and in consequence of those extremes, the leftover nonmetals. The first two "categories" are the way they elements involved have been described in the literature whereas the leftover nonmetals don't attract such language. In this case I tend to think that the wisdom of the masses and its delineation of the nonmetals into "naturally sharp" categories is as at least as good as the artificial sharpness in our hard line categorisation based on how many atoms happen to be in a molecule of the pure element.

As noted, extending the magic thread to Te, breaks the alternating diagonal-vertical sequence. I'm not sure what joining a diagonal-vertical-repeat thread (an orange) onto a group-based vertical-repeat thread (an apple) would achieve (apart from causing me to raise an eyebrow).

We currently call Se a polyatomic nonmetal and Te a metalloid even though Te is a polyatomic "not-metal", because the literature tells us that Te is counted as a metalloid 4 times more frequently than is the case with Se (98% v 24% according to lists of metalloids). The fact that Se happened to be polyatomic was a fortuitous bonus that enabled us to keep it grouped with its other polyatomic colleagues. There is no distinction between Se and Te in an atomic structure sense, since both are polyatomic.

Nothing essential changes with the proposed scheme. Te becomes a weak nonmetal (metalloid) and Se becomes intermediate, consistent with distinctions made in the literature. Sure S forms rings whereas Se forms chains but S does form long chains in plastic sulfur. The S-Se-Te triad is still there, and its natural category division is in the same place. The fact that there is a cross-cutting thread fortuitously and curiously running through the intermediate nonmetals is something I happened to notice afterwards. (And the presence of the thread does not mean there is no vertical link between Se and Te), just like the polyatomic-diatomic line between the same two elements doesn't.) Sandbh (talk) 04:47, 22 March 2017 (UTC)

Postscript: A possible alternative way of mentioning or considering the other relationships among the intermediate nonmetals is to merely observe H → C; C → P; and N → S, and not say anything about P → N and S → Se, since the latter two relationships are already part of the periodic table furniture. Sandbh (talk) 06:51, 22 March 2017 (UTC)

Okay, but surely most of the diagonal relationships come with the periodic table furniture as well: they are one of those things that you learn as you read the thing, sometimes to the point that you intentionally break some things to show some points. I have sometimes naturally wanted to talk about aluminium as if it were above scandium instead of above gallium, for example (and when R8R Gtrs writes the Al article I am looking forward to reading about that similarity). We also know of the linkages between groups n and groups n + 10 that used to be considered A and B subgroups; the "knight's move" relationships stretching across groups 11 to 13; the way the early actinides "pretend" to be transition metals; and so forth. Essentially, you start with a first-order rationalisation, and then keep adding adjustments to it, like some chemical analogy for a Taylor series. Just because not all of this is taught in high school (although I remember that Li–Mg and Be–Al were emphasised, and B–Si was mentioned but not treated in so much detail) does not mean that they are ignored totally: it just means that we're not ready for it then, but might be later.

Certainly the extremes exist, and similarities between the elements that are not clearly in the extremes also exist, but because there is a commonality leading through all of them as you pass through adjacent cells on the periodic table I am not so sure that the "magic thread" is particularly convincing as an argument. It actually feels more convincing to me to say that these elements are just somewhere in the middle, without appealing to the thread. So I see the only difference between the current and the proposed classifications is where we put hydrogen and nitrogen, right? I would note though that both are actually vigorously reactive, except that you have to heat them up first, whereas sulfur does not even need the heating: whereas diamond is extremely unreactive and graphite needs rather violent temperatures to react even with fluorine. Meanwhile black phosphorus is not very reactive at all (the element's reputation comes mostly from the white allotrope) and is even a semiconductor. The difference is mostly whether you can find simple anions as a matter of course, but even then, At would form At⁻, and with the reactive metals even Po forms "quasi-salts" like K₂Po. Double sharp (talk) 09:50, 22 March 2017 (UTC)

Other comments

• Symmetry, and " 4 + 4 = 8 symmetry components is cool". I get the feeling, but please take care not to use an outcome as an input argument. "It is symmetric so it must be something good" is not sound reasoning. The periodic table is full of exceptions, we'd not want to miss one this way (by being misguided seeing a non-existent regularity). -DePiep (talk) 12:07, 12 March 2017 (UTC)

I partly agree. I guess that is why I put it in as a footnote. I suspect Mendeleev would have approved :)

While there are irregularities, the overall pattern in the periodic table of strong metals to weak metals and weak nonmetals to strong nonmetals is very well recognised (not forgetting the noble metals and noble gases). Sandbh (talk) 06:09, 15 March 2017 (UTC)

DePiep's comments are brilliantly insightful. I would add one more thing, though: I find our current use of "polyatomic" and "diatomic" quite felicitous, because it relates the molecular structure of the pure elements to their chemical behaviour (even in compounds), thus linking together two slightly different things. Double sharp (talk) 13:22, 12 March 2017 (UTC)

Hmm. I like the polyatomic, diatomic and monatomic division too. This nomenclature is a bit different from the other categories, which tend to be more descriptive. That is, alkali, alkaline = caustic. Ln/An = like lanthanum/like actinium (these two are a bit more obscure); transition = going from one thing to another; post-transition = coming after the transition metals (these metals used to be called B metals, which at least conveyed the impression that they weren't as buff as the rest of the metals); metalloid = metal-like (mind you, the first time I saw this word I didn't know what it meant); halogen = salt former; noble gas = relatively inert. Polyatomic and diatomic describe the structures involved but don't tell you anything about the character of these nonmetals. And showing the progression in metallic to non-metallic character going across the periodic table is a bit harder to grasp with these two categories than it is with the alternative proposal. It certainly is easier to find references in the literature to this progression based on a first order observation of the nature of the elements as strong, transitional, moderate or weak metals or nonmetals, than it is to have to drill down and find explanations of the same progression based on crystalline structures.

It might come down to comparing the two options…

• polyatomic nonmetal ✦ diatomic nonmetal; or
• weak nonmetal (metalloid) ✦ intermediate nonmetal ✦ corrosive nonmetal,

…and working out which one is more information-friendly?

If our role is to summarise topics with an eye to toward broad-based, literature-supported consensus on subjects, then I think the alternative proposal has more consensus credibility. There is consensus that:

• relatively weak nonmetals are sometimes called metalloids
• oxygen, fluorine and chlorine are the most buff nonmetals; bromine and iodine are not quite so bad-ass but still in the same ballpark
• the remaining nonmetals (setting aside the noble gases) are described, more or less, using more moderate language.

There is consensus that diatomic and polyatomic nonmetals are diatomic and polyatomic but it is quite hard to find discussion in the literature on their other shared properties.

And if the way chemists tend to write is a reflection of the way they think, then they will think about the chemistry of different nonmetals in terms of where each nonmetal approximately lies on a composite scale (or spectrum) of nonmetallic "liveliness" or "intensity" rather than in terms of polyatomic or diatomic nonmetals. At one end of such a scale lie the corrosive nonmetals; at the other end are found the weakly nonmetallic metalloids. Sandbh (talk) 04:32, 20 March 2017 (UTC)

• Let's not forget, before we get used to these appearances: this is once again a wonderful great overview of element property & behaviour by Sandbh. Well researched & sourced, good to read, scholarly level. -DePiep (talk) 18:51, 12 March 2017 (UTC)
  • Hear, hear! Double sharp (talk) 04:12, 13 March 2017 (UTC)

Thank you!, DePiep and Double sharp. Sandbh (talk) 04:32, 20 March 2017 (UTC)

Antimony: Most stable oxidation state

The antimony article says that, "The +5 oxidation state is more stable." Is that right? I do know that the +3 oxidation state in Bi is more stable, and that Sb(V) shows less tendency to revert to (III) than P and As. Sandbh (talk) 02:58, 16 March 2017 (UTC)

Sb shows no reluctance to be oxidised to the +5 state, unlike As (another side effect of the 3d contraction). I would note that SbCl₅ exists and is reasonably stable, while AsCl₅ leads only a fugitive existence and even BiF₅ is vigorously reactive. I am not sure that I would say that +5 is "more stable" but I would have no problem with saying that like P, both +3 and +5 are important oxidation states for Sb. Double sharp (talk) 03:42, 16 March 2017 (UTC)

I am trying to do two things at once, so don't have time to to respond yet other than saying thank you and that I found a quote from an old piece of work I did once: "The higher valency state (+5) is the more stable in arsenic and antimony… The reverse is true of bismuth… Bi⁺⁵ compounds are uncommon." (Steele D 1966, The chemistry of the metallic elements, Pergamon, Oxford, p. 69). Perhaps that is where it comes from. More later. Sandbh (talk) 04:34, 16 March 2017 (UTC)

A more important question for that article: why isn't there anything about Sb cluster compounds, since the As and Bi ones are pretty well-known and get a mention in the articles for those elements? (Because they don't fit the chosen classification into Sb(III) and Sb(V) compounds, maybe?) Double sharp (talk) 03:47, 16 March 2017 (UTC)

Recoloring our PT

We had a great discussion on changing colors of the current categories about a year ago. I re-discovered my suggestion a few days ago and found it great. DePiep also had a draft for one but it at the moment didn't comply with the web design color criteria he introduced me to (DePiep acknowledged this, saying this would be worked on in a later revision).

Is anyone still interested in developing a new color scheme? I'd want to reignite the discussion for now if that's possible.--R8R (talk) 11:16, 17 March 2017 (UTC)

It's on my todo list for over a year, I'd very much like to redesign that. Colors we had have drawbacks, maybe full restart needed. Colorbrewer is a nice inroad. (Just finished an excercise with YBG for this). -DePiep (talk) 12:19, 17 March 2017 (UTC)

Could you explain to the amateur that I am what's wrong with them? I'd see if I could contribute some ideas for improving this if I knew what to do.--R8R (talk) 16:33, 19 March 2017 (UTC)

User:DePiep/pt-2016 is where we were at last year. I just edited them with Sc-Y-La-Ac and the new element names for Nh, Mc, Ts, and Og. Double sharp (talk) 16:09, 19 March 2017 (UTC)

That version is still far from it in terms of color contrast according to the standards DePiep introduced me to. For one, red on orange for nonmetals gives a contrast of 2.97 whereas we aim for 4.5. I resolved this at the price of having a not-so-red red, which I find to be a poor solution. I just got a new idea and I'll give it a try. Want to hear from DePiep on bad colors, though.--R8R (talk) 16:33, 19 March 2017 (UTC)

• Today, I'm working to update ~30 subtemplates of {{Chembox}} (and they might need a check & doc). Also working on: Template:Infobox uranium isotopes + Standard atomic weight series/issues.

Quick re (playtime ahead): Recently I worked with YBG towards this result. Intense, and very fruitful. See especially this table for the development. (Notes: only two editors were involved; just nine colors to solve—the PT needs ten+unk; bg-colors only, not yet text-contrast issues; and in between we did solve that Nixon-Cheney 36/46 issue).

I found some new improvements I want to introduce here: Colorbrewer.org (and its background research book) is very smart (in map coloring, so it is closely related. Nice to play with the options, read about colorblndness, and missing option 10...).

I also came up with my "al-most opposite color" theory. Will arrive here!

Will reply to (describe carefully) the topics mentioned (including contrast rules, and degrees-of-freedom).

Want to set this standard once and for all (though maybe not for ever). -DePiep (talk) 20:52, 19 March 2017 (UTC)

I'm already excited to see what you have there. Waiting for updates from you!--R8R (talk) 21:38, 19 March 2017 (UTC)

Periodic table form for first introduction

I think it worth considering, to introduce the periodic table initially in the left step form, and have all classrooms wallpapered with it. Instead of the crumbling-castle like figure.

• The advantages are, that the structure showing is much more regular (or just: regular). It nicely shows the shell-filling, inviting some pupils to ask: "why is that step two-rows high?" (send that pupil to a university for chemistry or physics).
• Of course the valence-ordering by I-VIII-0 groups is lost, partly. Ordering the groups by valence (1–8) of course was the original building principle for periodicity, being the discovering's entrance before electrons and orbitals were known (in 1871 and ever since the columns were already split into series A and B by M.—but is that really helpful for a first introduction btw?), but that does not say today we must introduce the periodic table that way. And for those who adhere to and 18-column form (any 18-column form): the f-block still nicely can be moved to the bottom again, where the irregular "f-block filling" can be avoided by omitting column headers.

How is the periodic table introduced anyway? I am open for teachers who say that one form or the other is way too complicated to teach. Note: this post is to datastamp this idea, although I probably am not the coining one. -DePiep (talk) 11:55, 21 March 2017 (UTC)

Well, the chemist's answer is that helium behaves nothing at all like beryllium. I would also add that this form makes the most salient divide look like it is between groups 2 and 3, when in reality it is at group 18 as the eye of a hurricane that envelopes groups 17 and 1. But the main reason is of course valence, since the standard format (if you ignore the d-block) lets you show a cute little picture like:

I	II	III	IV	V	VI	VII	0
H							He
Li	Be	B	C	N	O	F	Ne
Na	Mg	Al	Si	P	S	Cl	Ar
K	Ca

which shows you the first 20 elements lined up under the number of electrons in their outermost chemically active shell, taking 0 for the inert cases of He, Ne, and Ar. (Yes, yes, I know Ar can form a compound, but we're not going to tell them that yet.) We don't teach people to run before they can walk, so we start here first before going on into other elements and trends. Even then, we gingerly thread down the groups with the most similarities (I, II, VII, and 0) or the one with elements that everyone's heard of (IV), and then gingerly show the first row of transition metals to see what lurks beyond the first 20, enlarging it to 30. In fact, in some cases we might not even teach spdf until after the basics of the octet rule are finished (and first handwaving it as "there are exceptions and you'll learn them later"). It's only much later that we go to the rest of the 4th period, and most of the 5th, 6th, and 7th lie in darkness even when high school is finished. Everything needs to be progressive, after all! Double sharp (talk) 09:26, 22 March 2017 (UTC)

On the standard atomic weight

I am working to understand and improve the standard atomic weight and its related/unrelated quantities. Aim is to publish the right values with the right quantities (definitions, names, numbers, units, values, nonconfusing).

Main terms

• relative atomic mass (r.a.m.): physical quantity of a sample (any sample), reflecting isotopic composition of a single element in that sample. Dimensionless ('no unit', aka 'unit=1').

A_r

• standard atomic weight (s.a.w.): a r.a.m. for specific samples, as published by CIAAW. Specific samples: must be terrestial, natural, stable wrt radioactivity. Most commonly published value, especially in periodic tables. 84 elements have one.

A_{r, standard} (quantity symbol, my way of writing following SI). Examples:

helium: A_{r, standard}(He) = 4.002602(2). The "(2)" notes the uncertainty in the last digit (so read: 4.002602 ± 0.000002.

hydrogen: A_{r, standard}(H) = [1.00784, 1.00811]; an interval. No uncertainty added. Is not the same as an uncertainty range (rather, the sources differ systematically, eg H from ocean water and from air).

• Relative isotopic mass, mass number (more research needed. DePiep) (related: atomic mass, m_a; unit Da or u): mass of a single atom (i.e. a specific isotope).

Not published by CIAAW. Mainly used for the 34 instable elements that therefor have no s.a.w. (Tc and heavier metals from and beyond ₈₄Po).

Well, the full list to be precise is Tc, Pm, Po–Ac, and everything from Np onwards. Double sharp (talk) 14:36, 22 March 2017 (UTC)

Mass number: ²¹⁰Po = 210.

• Terms to be avoided: relative atomic weight, standard atomic mass, atomic weight (confusing)

Derived from standard atomic weight:

• conventional atomic weight: single s.a.w. value for interval. CIAAW published. Example:

A_{r, standard}(H) = [1.00784, 1.00811] → A_{r, conventional}(H) = 1.008

• abridged atomic weight: s.a.w. value, rounded to 5 significant figures maximum, has uncertainty or is again an interval. CIAAW published.

A_{r, standard}(He) = 4.002602(2) → A_{r, abridged}(He) = 4.0026(1) (note: "(1)" is usually omitted, but not "(2)").

Work in progress

Main: Use "standard atomic weight" and its value where possible, and not where not applicable. The CIAAW value is sacred. Root out wrong or misunderstood usage.

Standard atomic weight: new article, should cover CIAAW aspects. Started with text copied from Relative atomic mass, to be teared apart.

In Wikidata: trying to have properties accepted. proposal:Property s.a.w., proposal:Property r.a.m.. Not an easy exercise.

References

Published table: "Standard Atomic Weights". Commission on Isotopic Abundances and Atomic Weights (CIAAW). 2015. Retrieved 2015-09-20.

Technical Report 2013: Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

CIAAW update 2017: s.a.w. of ytterbium was formally changed into 173.045(2).

Questions, todo

• Improve core articles
• Use {{val}}, produces spaced numbers: 4.002602(2).
• Clarify which term to use for non-s.a.w. (instable elements).
• What to have in our infoboxes? Which labeltext, data values. s.a.w.: always when exists (84×), Conventional: sure; abridged: no. What with instable elements (that have no s.a.w)?
  • Unstable elements use the mass number of the isotope with the longest half-life in square brackets. So Tc gets "[98]" and Pm gets "[145]". Although what I might want to do is to put a little table in the article (not the infobox) giving the A_r of the most common ones (Po would have 207.9812, 208.9824, and 209.9828 for ^208,209,210Po respectively). Double sharp (talk) 09:15, 22 March 2017 (UTC)

So 'Mass number' should be the labeltext in these situations, definitely not s.a.w. Maybe a minor explanation with it (isotope symbol).

I think the three values you give are not an A_r (dimensionless, and from actual samples) but are an isotopic mass or a relative isotopic mass (per specific isotope, no averaging done). Could be a true mass (in Da) or relative (dimensionless when divided by 1 Da)). btw the isotopic mass (in Da)is in isotopes of Po. -DePiep (talk) 09:46, 22 March 2017 (UTC)

-DePiep (talk) 14:03, 21 March 2017 (UTC)

Good catch, though in this specific case I do mean A_r. This is because a realistic sample of Po will usually only contain one of the isotopes: you select for them by deciding what to bombard your bismuth target with, and at what energy, and then one will dwarf all the others in the amount produced. I agree with you, though: we should probably not label them as such in general. Double sharp (talk) 14:36, 22 March 2017 (UTC)

About the new isobox, developing. For isotopes of oganesson I made and added {{infobox oganesson isotopes}} (a full copy from {{infobox oganesson}}). Intention is to add this to oganesson#isotopes section too (and remove table from main infobox). When done, those isotopes masses could be added to that box (Oganesson is a trivial example with just one isotope). -DePiep (talk) 09:56, 22 March 2017 (UTC)

Hmm, but I do think that I would want some consistency in what the infobox contains, and it seems to me that the visible elements should set the tone, no? The isotopic abundances are an important properties of the element as it naturally occurs and so I think the major isotopes should be in there.

One thing I do want is an extra column squeezed in for nuclear spin, which is very important for NMR. Double sharp (talk) 14:32, 22 March 2017 (UTC)

Why I periodically write about the elements on Wikipedia

Thought you might be interested. A couple of weeks ago, I was contacted by Wikimedia staff member Ed Erhart; he asked me if I would write an article for Wikimedia blog about why I keep writing articles about the elements, to which I agreed. Just very recently, it went live and you're free to give it a read :)

BTW sorry for not being able to take part in the discussion of the scheme proposed by Sandbh. I have a lengthy reply in mind but I am unable to write it down for the next couple of weeks (or more) due to lack of spare time.--R8R (talk) 08:17, 22 March 2017 (UTC)

Ye gods, the fluorine article really did suck back then, didn't it? ^_^ And thanks for the mention!

I am very much amused by your description of why you chose F. In fact, it was for much the same reason that I went for alkali metal (well, that and the thought process "why write on all six individually, when I can just put them all together?"). Then I kept finding more stuff and more stuff and it's become incredibly long. I would note by the way that doing what we did has become a lot harder for the element articles (too many have been done), except maybe in the lanthanides (which are really boring to do: maybe I'll finally dust of praseodymium, which is mainly notorious for its impossibly long name). The ripest pickings for those who want to do this kind of thing are probably group articles: alkaline earth metal and halogen are good choices (but certainly not any of the others). I should also take this opportunity to clamour for the much-anticipated Sandbh rewrite of transition metal. ^_^

And indeed, despite being the closest thing we have to a resident Stakhanov at the moment (who nevertheless sees fit to disappear for a few months at a time), I fully appreciate that we can't possibly do everything all by ourselves. Double sharp (talk) 09:12, 22 March 2017 (UTC)

Having worked on some of your (R8R's) articles it is remarkable how much your Wikimedia article adds to you as a real person, rather than someone I usually think of as R8R Gtrs. That was a good read. I shall wait patiently until you are ready to provide some comments on my proposed scheme (and for the return of YBG). Meanwhile I think I'm still learning about the scheme (= sharpening my approach) in the course of my chat with Double sharp. The transition metal article rewrite is still there in the background, as is some more work DS and I have been asked to do on the Group 3 question, and then there is the lead FAC to get ready for again, and I have another RL commitment coming up soon, followed possibly by further university studies, so who knows when I'll get round to everything. No matter. Sandbh (talk) 11:49, 22 March 2017 (UTC)

Indeed, please take my comments as an attempt to focus the spotlight on the issue! Regarding group 3, I have also been mulling about the block-definition thing (and how there does not seem to be an agreement as to exactly how the blocks are defined): you will see this when I feel it is ready for your comments (which is a status it is not anywhere near yet ^_^).

P.S. to R8R: "Soviet-styled" is now in my mental dictionary as a synonym of "the highest quality of pure scientific scholarship". ^_^ Double sharp (talk) 12:12, 22 March 2017 (UTC)

LOL! Sandbh (talk) 12:32, 22 March 2017 (UTC)

I like how you mention Au as a far-future project, BTW. It is another of those things I have wanted to tackle in a group, but have a phobia of doing alone.

Silver is a good example of this sort of phobia: the first three sections, dealing with the properties of the element, are fine, but doing the rest of the article absolutely terrifies me. I got over it for iron mostly because there was already a good base there and all I had to do was to find citations. I will definitely need a PR for this to continue further into applications, history, and the cultural background. Double sharp (talk) 15:15, 22 March 2017 (UTC)

Calcium, strontium, and barium

Has anyone actually ever seen any of these three elements (except Sr in the fabulous Wikipedia picture) without an oxide layer? Only in the aforementioned fabulous WP picture do you see the "pale yellow" colour that Greenwood and Earnshaw refers to on page 112. (Same goes for europium and ytterbium.) Double sharp (talk) 15:10, 22 March 2017 (UTC)