Talk:Transition metal

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Shielding and Gold[edit]

While the article states: "The number of oxidation states of each ion increases up to Mn, after which they decrease. Later transition metals have a stronger attraction between protons and electrons (since there are more of each present), which then would require more energy to remove the electrons."

Would it not be more proper, this being a chemistry article and all, to invoke the concept of shielding, instead of beating around the bush.
Secondly, I was wondering should a discussion be done about golds aberrant yellow color. Which I have the understanding (from undergrad inorganic) is due to the 5d contraction as a result of relativistic mass coming into play. --PedroDaGr8 00:33, 22 April 2007 (UTC)


"In fact Ca3+ has an ionisation enthalpy so high that it rarely occurs naturally."

Are you sure? I never, ever heard of naturally occurring Ca3+! Sounds suspicious to me... --malbi

I suspect this is true that it never occurs naturally. I think this paragraph should be reworked; it's too much about calcium and group II and not enough about transition metals. Olin
I went and revised it. Olin


There seems to be an inconsistency in this article: Not all d block elements are transition metals. Scandium and zinc don't qualify..., yet both scandium and zinc are listed in the table at the top of the article, and shown as transition elements in the periodic table. Scandium is stated to be a transition element in its article, zinc is not so described in the text but is in the infobox. Possibly the definition is not agreed by all authorities, or has changed recently? Andrewa 22:07, 17 Sep 2004 (UTC)

Whatever the historical cause, it seems that there are now two commonly accepted definitions of transition element and transition liquids. Although I am not a chemist I have had a go at fixing the article. It may still not be entirely accurate, and is not perfectly phrased, but I am confident that it is both better phrased and more accurate than what I started out with. Andrewa 14:07, 26 Jan 2005 (UTC)
I corrected this to the best of my knowledge. From looking at books and on the web, I still think 99% of all chemists consider scandium to be a transition metal. Hence, I referenced the IUPAC definition, which would discludes cadmium. I also did some general cleanup; the article still, however, clearly needs help. Olin
The reason that some dont consider it a transition metal is because it actually fills up the 4s electron orbital rather than the 3d. Notice the exception for copper can chromium in the chart on Electron_configuration. All4One 19:32, 8 October 2006 (UTC)

From PNA/Chemistry[edit]

  • Transition metal - I raised some issues with this article on its talk page some months ago and got no response. I have now rewritten the introduction to be consistent with the usage of the term elsewhere in Wikipedia, notably in the periodic table and in the articles on the transition elements themselves. But I'm relying on high school chemistry, many years ago. In view of the technical nature of some of the material and the very significant changes I have made just to the introduction, I think the whole article needs a review by someone more knowledgable. I was going to list it for peer review but the function of that page is now linked to featured articles, and so now there doesn't seem to be better a place than this to request the old sort of peer review, which is what is needed. Andrewa 03:16, 27 Jan 2005 (UTC)

four periods[edit]

I'm concerned at one change I have made. Previous text (emphasis mine):

This name comes from their position in the periodic table of elements, which represent the successive addition of electrons to the d atomic orbitals of the atoms as one progresses through each of the three periods.

My version (again, emphasis added):

The name transition comes from their position in the periodic table of elements. In each of the four periods in which they occur, these elements represent the successive addition of electrons to the d atomic orbitals of the atoms.

I'm not sure what was meant by three periods. Did it mean the three following periods, making four in all? Or was it just a mistake, and if so why am I the first to notice it? Or is there something I have misunderstood? Andrewa 20:35, 26 Jan 2005 (UTC)

This has now been explained to me. Four is the correct number (whew), the probable reason for the earlier version saying three is that all transition elements in the fourth period in which transition elements occur are radioactive, with all their isotopes having sufficiently short half-lives that exploring their chemistry is a bit problematic, my informant actually said most do not have any substantial chemistry but I suspect some of my old AAEC collegues would disagree here, they regarded positronium as having substantial chemistry and were exploring it on the big (to us) Van de Graaff.
The upshot is, while there were traditionally three periods of transition metals, now four are recognised... and there seems to be a consensus on that much, anyway. Andrewa 19:12, 17 July 2005 (UTC)

table of elements[edit]

I recommend that the table showing the transition metals be rearranged into horizontal periods and vertical groups like they would appear on the periodic table. I don't have enough wiki experience to try it for myself to see how it would look. If there is a good reason why the table is like this, I would at least like to know why. 17:42, 1 Mar 2005 (UTC)

No idea why the original author put it there, but it seems to me that a flipped table would squeeze out most of the running text. YMMV. --Christopher Thomas 19:43, 16 May 2005 (UTC)

Yes, the flipped table is too wide to run on the right side, but seems short enough to give its own space to. So I've changed:

Group   Period 4 Period 5 Period 6 Period 7
3 (III B)   Sc 21 Y 39 Lu 71 Lr 103
4 (IV B)   Ti 22 Zr 40 Hf 72 Rf 104
5 (V B)   V 23 Nb 41 Ta 73 Db 105
6 (VI B)   Cr 24 Mo 42 W 74 Sg 106
7 (VII B)   Mn 25 Tc 43 Re 75 Bh 107
8 (VIII B)   Fe 26 Ru 44 Os 76 Hs 108
9 (VIII B)   Co 27 Rh 45 Ir 77 Mt 109
10 (VIII B)   Ni 28 Pd 46 Pt 78 Ds 110
11 (I B)   Cu 29 Ag 47 Au 79 Rg 111  
12 (II B)   Zn 30 Cd 48 Hg 80 Uub 112


Group 3 (III B) 4 (IV B) 5 (V B) 6 (VI B) 7 (VII B) 8 (VIII B) 9 (VIII B) 10 (VIII B) 11 (I B) 12 (II B)
Period 4 Sc 21 Ti 22 V 23 Cr 24 Mn 25 Fe 26 Co 27 Ni 28 Cu 29 Zn 30
Period 5 Y 39 Zr 40 Nb 41 Mo 42 Tc 43 Ru 44 Rh 45 Pd 46 Ag 47 Cd 48
Period 6 Lu 71 Hf 72 Ta 73 W 74 Re 75 Os 76 Ir 77 Pt 78 Au 79 Hg 80
Period 7 Lr 103 Rf 104 Db 105 Sg 106 Bh 107 Hs 108 Mt 109 Ds 110 Rg 111 Uub 112

Please leave a message on my talk page if you want any additional formatting changes. -- Rachel 20:42, 15 August 2005 (UTC)

The periodic table of the transition elements[edit]

Group 3 (III B) 4 (IV B) 5 (V B) 6 (VI B) 7 (VII B) 8 (VIII B) 9 (VIII B) 10 (VIII B) 11 (I B) 12 (II B)
Period 4 Sc 21 Ti 22 V 23 Cr 24 Mn 25 Fe 26 Co 27 Ni 28 Cu 29 Zn 30
Period 5 Y 39 Zr 40 Nb 41 Mo 42 Tc 43 Ru 44 Rh 45 Pd 46 Ag 47 Cd 48
Period 6 L Hf 72 Ta 73 W 74 Re 75 Os 76 Ir 77 Pt 78 Au 79 Hg 80
Period 7 A Rf 104 Db 105 Sg 106 Bh 107 Hs 108 Mt 109 Ds 110 Rg 111 Cn 112

why there is only 8 groups in periodic table and not more?[edit]

I want to know why the outermost shell of atom only have at most 8 electrons?But the previous shell can have 18,32...?

  • Because a new shell is always started after 8 electrons even if there is room for more electrons to go in; the partly filled shell is completed later. (note this is only true for atoms, not ions) Physchim62 (talk) 15:03, 19 November 2005 (UTC)

why a new shell is always started after 8 electrons?

  • Because, for an atom (not for an ion), the nd sub-shell is higher in energy than the (n+1)s sub-shell. Physchim62 (talk) 08:02, 20 November 2005 (UTC)

what is the difference between ion and atom?

  • An atom has the same number of electrons as protons, and so has no electrical charge. An ion has more or fewer electons than protons, and so has an electrical charge. The energies of the different shells depends on the number of protons and on the number of electrons—the enrgies are different for each element, but the order is roughly the same. Physchim62 (talk) 08:12, 20 November 2005 (UTC)

is ion stable?[edit]

are ions sable since they have gained or lost electrons?

Please sign your posts on talk pages, even if not logged in. Andrewa 08:50, 4 February 2006 (UTC)

Definition (again), zinc, scandium and now cadmium[edit]

See Wikipedia talk:WikiProject Chemistry#Transition metals. Andrewa 08:50, 4 February 2006 (UTC)

A user's comment[edit]

A user with IP address put the following comment into the article itself. I removed it from the article, but it sounded well-meaning rather than intentional vandalism, so I'm copying it here. The comment said: "Transition metals change all the time. They just change from one metal to another. You can get a peice of gold and can get platinum or any of the transition metals. It has a cool rippleing effect." NOTE: I (user elysdir) know nothing at all about the topic nor about this particular comment, so please don't ask me about it. I'm simply moving another user's comment from the article body to the Talk page. --Elysdir 17:39, 30 November 2006 (UTC)

It was vandalism. Double sharp (talk) 07:53, 20 January 2012 (UTC)


Iron in the picture is listed as having a common +5 oxidation state. I don't think that's right. I think it's absolutely extremely rare. Olin 19:32, 17 April 2007 (UTC)

The image is wrong in numerous other points as well. Someone give me a ping when I get back to France in a couple of days and I will get the data together for a corrected version. Physchim62 (talk) 21:25, 17 April 2007 (UTC)
I suggest using the figure from chapter 2 of Greenwood, which is more comprehensive as it also includes negative oxidation states. The current figure is unsourced, which makes me wonder who decided which oxidation states should be included as "common" and "less common". --Itub 12:05, 15 October 2007 (UTC)

Are noble metals also transition metals?[edit]

I saw the definition here to be: "More strictly, IUPAC defines a transition metal as an element whose atom has an incomplete d sub-shell". This is supposed to exclude zinc, cadmium and mercury and leave groups 3 to 11 in the definition. The noble metals (copper, silver and gold) however have also a filled d-shell (according to Why are they called transition metals as well then? Erwin 15:34, 3 September 2007 (UTC)

Because they easily form ions with incomplete d shells. --Itub (talk) 11:04, 21 November 2007 (UTC)

Are you serious?[edit]

Are you serious? You don't have a picture of a periodic table displaying which metals are the transition metals? I have to read to figure it out? How can you be serious? —Preceding unsigned comment added by (talk) 02:00, 14 February 2008 (UTC)


It would be nice to get some general trend as to the conductivity of transition metals. Someone knowledgeable on this subject please add this into the main article. Thanks. Gautam Discuss 22:56, 15 May 2008 (UTC)

IUPAC definition for transition metals[edit]

NOTE: This section is transcluded so the widest-possible number of people can comment

I've been auditing the nav images in element articles to fix wrong neutron counts and giving Lu and Lr the lanthanoid and actinoid coloring, respectively. Part way through, I started to review our definitions for element categories to check them against IUPAC's provisional recommendations. See IUPAC Red Book IR-3.6 GROUPS OF ELEMENTS. Turns out that their specific definition for transition metal deviates from ours in a somewhat embarrassing way:

  • IUPAC defines transition metals specifically as being those elements in groups 3 to 11. This excludes the group 12 elements!

ED NOTE: Turns out, that IUPAC's approved recommendations define transition metals as either the set of elements in groups 3 to 12 (our current set-up) or the set of elements from 3 to 11 (the set-up in the below table).

Fixing this results in somewhat modified periodic tables (Note, that the expanded 'Other metal' category includes all the post-transition metals plus aluminium):

Table showing the more IUPAC consistent element categories

So, before I finish my audit and fix of the nav images, I'd like to know if I should fix group 12 to be consistent with the provisional IUPAC definition of transition metals. OR should we wait for IUPAC to come out with the final-updated Red Book (comment period ends at the end of 2008)? I'm putting my audit and update of the nav images on hold until we figure this out. --mav (talk) 17:50, 5 October 2008 (UTC)

I am not sure how many agree to this definition so waiting would be ok. Nergaal (talk) 18:10, 5 October 2008 (UTC)
I just checked one of my college chemistry textbooks and it agrees with IUPAC. If this definition for transition metals is already widespread, then we may not need to wait for IUPAC's final revision of the Red Book. On the other hand, the updated document may impact other parts of the table and / or nav images. I'm simply not sure how or when we should proceed. --mav (talk) 18:18, 5 October 2008 (UTC)
Erm, the comment period ended in 2004, according to the root of the file you quoted. The text approved in 2005 was (p. 51):

The elements (except hydrogen) of groups 1, 2 and 13–18 are designated as main group elements and, except in group 18, the first two elements of each main group are termed typical elements. Optionally, the letters s, p, d and f may be used to distinguish different blocks of elements. For example, the elements of groups 3–12 are the d-block elements. These elements are also commonly referred to as the transition elements, though the elements of group 12 are not always included; the f-block elements are sometimes referred to as the inner transition elements.

As far as I'm aware, there are no new inorganic recommendations planned for four or five years or so (until they get round to sorting out inorganic Preferred IUPAC names). Physchim62 (talk) 18:25, 5 October 2008 (UTC)
Ah - I saw this and assumed it also applied to the inorganic nomenclature. My bad. I also remember something about unfilled d-suborbitals as part of the definition, which also excludes group 12 elements (with a complication with at least one Hg compound). --mav (talk) 18:35, 5 October 2008 (UTC)
Definition of this term has always been a problem- whether to base the classification on chemistry or atom electron configuration. I was taught at school (1942 Sherwood Taylor text book) that the transition metals did not include Cu group and Zn group - only then to be told at university that Cu was a transition metal. IMO we should go with current IUPAC - that definition has been around for at least 40 years (Cotton and Wilkinson 2d edition 1966)- it leaves a little problem of colouring in and explaining the position of Zn group which is neither main group nor transition metal, but is in the d block according to our chart- although the chart conflicts with the definition in the article (sic "..highest energy electron is in a d orbital") which would seem to exclude both copper (3d10 4s1) and zinc (3d10 4s2) - if our list of electron configurations is right. Best of luck.--Axiosaurus (talk) 08:32, 6 October 2008 (UTC)
The current IUPAC definition (quoted above) gives us freedom to include group 12 or not. Let's not forget that Cotton & Wilkinson doesn't class scandium and yttrium as transition metals either, on chemical grounds. Greenwood and Earnshaw agrees with our current classification except for lanthanum and actinium, which they (correctly in my view) class as transition metals. I seem to remember that the edition of Sherwood Taylor that you quote classes thorium and uranium as transition metals and, in the case of thorium ([Rn] 7s2 5d2), a naive or dogmatic application of the electron configuration criterion would force us to do the same! Physchim62 (talk) 08:52, 6 October 2008 (UTC)
IMHO IUPAC does not clearly define the matter, that's why such a long discussion is needed. My experience is very close to the Axiosaurus' one. The first simple definition refers to empty d orbitals at the elemental state whereas at university I was taught that it's more useful to include group 11 (Cu, Ag, Au) as well because they form ions having empty d orbitals - that is the Cotton Wilkinson definition. This is supported by their behaviour, for instance because they can form coloured complex as the other transition metals. I've never heard that the 12th group (Zn, Cd, Hg) can be included in the transition metals because their behaviour, i.e as catalist, is completely different than the others due to their full d shell. Most of my teachers would have marked as a serious mistake. Cotton Wilkinson (III edition, 1972) includes Scandium and Yttrium between the transition metals. Chemical behaviour should prevail as even Mendeleev based and actually built the periodic table on this characteristic. Some authors try to bridge this describing group 3-12 as d block. Please do not be misled by the shape of the periodic table or, worse, by aestetics issues. Chemistry is an experimental science and sometimes cannot be oversimplyfied. --Avogadro-I (talk) 22:46, 24 November 2008 (UTC)

I've always thought that our periodic tables have too many colors and that we could save ourselves a lot of trouble if we got rid of most of them. But I'm afraid I'm in the minority. --Itub (talk) 10:46, 6 October 2008 (UTC)

But the table is so purty with the colors! And we'd have one less thing to argue about discuss - that would be boring. ;) --mav (talk)

Great feedback - thanks for finding the the current recommendations. Looks like IUPAC is giving us some leeway in the definition of transition metals in the approved recommendations. That means that our current table does not conflict with IUPAC. That is all I was worried about. We should therefore leave well-enough alone. We can revisit this if/when IUPAC comes up with a more rigorous definition. But I welcome anybody else to comment just in case we have missed anything. Again - Thank you everybody! --mav (talk) 01:03, 7 October 2008 (UTC)

Yes, my own opinion is that it's one of those debates that creates more heat than useful work! Physchim62 (talk) 01:21, 7 October 2008 (UTC)
And don't forget that Wikipedia:Naming conventions (chemistry) allows us to go againt IUPAC occasionally, when circumstances demand it! Physchim62 (talk) 01:27, 7 October 2008 (UTC)

It looks like I may be getting in here a little late, but I just wanted to note that in post-transition metal, it claims that the IUPAC definition for transition metals is in conflict with it self. Based upon what I've read here, that doesn't seem to be the case any more. I think it needs to be cleaned up to match the above conclusions. --Wizard191 (talk) 02:04, 8 October 2008 (UTC)

Just a note: first time we get the chance, we should try to get rid of the color differenciation between actinoids and lanthanoids. Nergaal (talk) 17:22, 15 October 2008 (UTC)

Why and what would replace it? --mav (talk)
does not add enough information, and within the TMs, the variations in chemistry are larger than those between Ac and Ln's. Any of the two colors used now would be fine, or some random mix of the two too. Nergaal (talk) 15:16, 19 October 2008 (UTC)
The actinides and lanthanides are distinct enough for us to label them as separate element categories. That combined with the lack of consensus on what is an inner transition tells me that we should leave well enough alone. --mav (talk) 01:06, 20 October 2008 (UTC)

Mercury is considered a transition element under both IUPAC definitions now, because the compound HgF4 has been synthesized in 2007, giving Hg a d8 electron configuration. Should this be incorporated in the table and the article? Kumorifox (talk) 13:46, 18 May 2009 (UTC)

Not everyone agrees that mercury is a transition metal due to the observation of HgF4 under exotic conditions. See the article on HgF4 for details. --Itub (talk) 01:12, 19 May 2009 (UTC)

Removing suggestion to Merge d-block and Transition metal[edit]

Well I showed up 3 months too late for the fun, but I based on what I read, I am removing the suggestion to merge these two articles. No change in IUPAC recommendations will ever alter Periodic table (by blocks). The blocks must have a number of columns corresponding to the number of electrons that a full subshell can hold. So the d-block must occupy groups 3-12. This is a man-made oversimplification because the chemistry and even the ground state electrons in Periodic_table_(electron_configurations) are messier than the blockiness, but that's ok. Oversimplifications are important because they make reality interesting. "Transition metal" on the other hand, is a convention, not an oversimplification. One bunch of folks call some elements "Transition metals" and another bunch of folks don't, and IUPAC says that's ok. When the most recent IUPAC book says "the elements of group 12 are not always included," they mean not always included in the transition metals. Group 12 has to be in the d-block because if it weren't, then the d-block would only hold 9 columns, meaning 9 electrons maximum in the d-subshell and Kimmie, the cute new 22-year old high-school chemistry teacher, would cry because even the oversimplifications would be too complex to teach, and angry mobs of high school boys who love Kimmie would grab torches and pitchforks and attack IUPAC folks and Wikipedia editors for making Kimmie cry. So that's why d-block and Transition metal should not be merged even though IUPAC says they -can- contain the same elements. By the way, Inner transition element and f-block should also be separate articles for the same reason. Conventions and oversimplifications are very, very different. Flying Jazz (talk) 07:47, 18 January 2009 (UTC)

I agree and I'm glad to see you editing again. :) --mav (talk) 15:40, 19 January 2009 (UTC)
Well, if Kimmie is wrong, too bad I say. (^_^) Other than that, I agree they should remain separate articles (though that's probably because I am of the firm opinion that the d-block and the transition metals should be different groups). Double sharp (talk) 04:52, 15 September 2013 (UTC)

Regional spelling system[edit]

Following on from comments in the edit summaries regarding spelling. WP:ENGVAR has no preference for any spelling system but does require consistency throughout the article. This article has a mixture of British and American spellings. For cases where the subject is not identifiably either English or American ENGVAR says that the spelling should follow that of the first major contributor or the first contributor to make an edit that disambiguates the variety. The very first edit seems to be an import from Nupedia in 2001 with the edit summary spellinhg (sic). It is very short and has no words that disambiguate spelling other than the link to sulfur which is merely the name of the linked article. This is followed by a substantial series of edits by user:Sodium which is beyond doubt using the British spelling system. On that basis I would say the article should be standardised on British spelling. Does anyone else have any comments? Does anyone else care? SpinningSpark 02:09, 16 February 2009 (UTC)

I care! I care that we don't waste time arguing over it! Thanks for the research Spinningspark! There is a talk page template for this sort of question, {{British-English}} (and its various equivalents for other regional varieties): I won't hoist the Union Flag until others have had a chance to comment though. Physchim62 (talk) 08:52, 16 February 2009 (UTC)

Valence electrons[edit]

"Transition metals are metals with one or two valence electrons"-- should this be qualified with "typically", or otherwise expanded to account for Palladium? Tom239 (talk) 19:02, 8 March 2009 (UTC)

No, it needed to be deleted as patently untrue! The whole concept of "valence electrons" is a bit tricky for transition metals. Physchim62 (talk) 19:08, 8 March 2009 (UTC)

Groups A or B of periodic table? Both were correct.[edit]

Today user changed the alternate labels of Groups 3-10 to read IIIB - VIIIB, and then user Shootbamboo reverted these labels to read IIIA - VIIIA. Actually as explained in Group (periodic table), both numberings are (or were) correct since the first is the old American system and the second is the old European system. The modern IUPAC numbering (Groups 1-18) was introduced in order to eliminate this confusion.

Since both the old numberings have been superseded by IUPAC, I think this article should mention either both or neither. I prefer neither - just number the transition metal groups from 3 to 12 (if Zn,Cd,Hg are included). Dirac66 (talk) 02:57, 13 May 2009 (UTC)

No strong preference here. -Shootbamboo (talk) 00:33, 14 May 2009 (UTC)
OK, thanks. I have opted for neither and retained only the modern IUPAC numbering (3-12), as in the intro paragraphs and in many other Wiki articles. Dirac66 (talk) 01:23, 14 May 2009 (UTC)

oxidation states of platinum[edit]

Platinum does have a +6 oxidation state, as in platinum hexafluoride, however, this isn't reflected in the table under "Variable oxidation states". Similarly, gold(V) fluoride also exists, showing that the post-group-8 trend in period 6 is higher than this table would indicate. Can someone update this table?—Tetracube (talk) 03:40, 25 June 2009 (UTC)

P.S. For that matter, platinum also has a +5 state, in PtF
(see the platinum hexafluoride article).—Tetracube (talk) 03:43, 25 June 2009 (UTC)

The +5 state is also found in the PtF6- anion, also mentioned in the PtF6 article. Dirac66 (talk) 22:17, 27 June 2009 (UTC)

Electronic structure exceptions[edit]

To Peter Gans: Your ongoing rewrite is in general very good. However the following sentence seems to be too general and ignore the exceptions:

The electronic structure of transition metal atoms can be written as ns2(n-1)dm, as the inner d orbital has more energy than the valence-shell s orbital. In compounds of the transition metals the situation is reversed so that the s electrons have higher energy.

I would suggest: The electronic structure of MANY transition metal atoms can be written as ns2(n-1)dm, as the inner d orbital has more energy than the valence-shell s orbital. In MOST IONS of the transition metals the situation is reversed so that the s electrons have higher energy.

Comments: MANY because Cr, Cu, Pd etc are exceptions. Pd in fact has no 5s electrons. IONS as for your examples. The orbital order in compounds is a much more complex subject; first of all the experimental results are for molecular orbitals which cannot always be identified with atomic orbitals. And MOST because there are exceptions too, especially the 1+ ions. Dirac66 (talk) 15:12, 25 August 2009 (UTC)

You are, of course, correct regarding exceptions for atomic orbitals. I also agree with your comment about orbitals in molecules. I think I has the divalent and trivalent ions in mind when I wrote that bit. With the lower and higher oxidation states covalency is much more important. I'll seek to clarify the text. Petergans (talk) 18:19, 25 August 2009 (UTC)

The metals[edit]

So let's decide what metal should be considered transition. I think, groups 4-11 metals are unbeatably transition, so no more about them. I just don't understand why my version of 20 July 2010 was considered so wrong (no, it wasn't 100% right, I admit! But still better than that of today). 'Twas neutral; I've never heard Sc and Y to be not transition, so that's my dominant; but I recognize some may disagree so I mentioned it; Same thing on group 12 elements (but I guess I was some wrong there; only mercury is 100% transition since there's no a definition not allow it to be something else - read mercury(IV) fluoride; according to IUPAC, zinc and cadmium are not transition). Also, my words about group 3, periods both 6 and 7 were also ignored (where it was really neutral! I've spit on my own opinion these should be Lu and Lr, not La and Ac). Also, I guess, it should be mentioned that according to IUPAC, uranium is transition metal (along with thorium, cerium, curium, gadolinium, neptunium, protactinium (and elements of 3-11 groups plus mercury)), since their atoms have d electrons. Also, La, Ac and Lu also have d electrons but Lr doesn't, being (huh!) a main group element (or else but still not transition to IUPAC). Of course, it doesn't have to be article's base but at least should be mentioned.

But currently, instead, article names Sc and Y mostly considered not transition, not mentioning why they can be (I mentioned why they can be considered not transition). Lu and Lr aren't even mentioned at all, although they're at least same possible to be transition. And, what's worse, article says "Zinc, cadmium, and mercury are not transition metals." Mercury definitely is, as proven before. Zn and Cd may be, and may not be. I think saying "Zinc and cadmium can be counted as both transition and not transition, as they have no compounds with incomplete d shell but traditionally they can be counted transition. Mercury should be mostly considered transition but it was not known before 2007 that it can have incomplete d shell, so in some cases it is still counted not transition, and also in some cases can be as its two lighter homologues are not transition. Today, there is no definition which makes mercury not transition" or something like that. Hope, my words won't be missed--R8R Gtrs (talk) 17:38, 23 October 2010 (UTC)

Group 12[edit]

The debate over whether mercury should now be considered a transition metal is reviewed in the article on mercury(IV) fluoride. Since there are authoritative opinions on both sides of the question, I have changed the article to mention this controversy, as per Wikipedia NPOV policy, with a reference on each side.

For Cd and Zn no compounds have been prepared (to date) in oxidation states higher than II, so they are not considered as transition metals by the IUPAC definition.

I will think more about Group 3.Dirac66 (talk) 17:56, 24 October 2010 (UTC)

Group 3 and f-block[edit]

I have now revised the article concerning group 3 and the f-block. For Sc and Y every source I checked classifies them as transition metals, so I deleted the statement that they are not. For La-Lu and Ac-Lr I found three different opinions, so I have included all three. There seems to be no consensus on the classification of these elements. Dirac66 (talk) 23:57, 6 November 2010 (UTC)

[1] states that neither Sc nor Zn are transition metals. It does not discuss the lanthanides and actinides. Double sharp (talk) 07:56, 20 January 2012 (UTC)

Sign posts on pages when not logged in[edit]

Why should you sign your posts?
How do you sign posts when not logged in? —Preceding unsigned comment added by Wd930 (talkcontribs) 01:29, 5 December 2010 (UTC)

You sign your posts since a record of a discussion should include information on who said what. To sign in without logging in, you could just sign manually by typing out your Wikiname.Dirac66 (talk) 03:56, 5 December 2010 (UTC)


I demoted the article from C-class to Start-class a while ago because of the fact that it mentioned the two alternative definitions of transition metal, only to dismiss one as "historical" although it is obviously still current, and not to discuss the other further. Lanthanum-138 (talk) 13:22, 7 May 2011 (UTC)

Perhaps the intro should not use the phrases "In the past" and "modern". I suggest the following changes in the intro to restore neutrality:
  1. Change "In the past the term transition metal referred to any element ..." to "Some authors describe as a transition metal any element ..."
  2. Remove "modern" before "IUPAC" but place the IUPAC definition first.

Dirac66 (talk) 15:32, 7 May 2011 (UTC)

Addressing these points. Lanthanum-138 (talk) 14:00, 12 May 2011 (UTC)
Done. Back up to C-class now. Lanthanum-138 (talk) 14:03, 12 May 2011 (UTC)
Ok, all is good now except for the reference to Jensen, who actually reviews both usages and several others dating back to 1920. I'll put that he has reviewed the history of the term. Dirac66 (talk) 14:22, 12 May 2011 (UTC)


I would find it helpful if this article had a table giving for each transition metal the most common ions/oxidation states found in compounds. — Preceding unsigned comment added by Skysong263 (talkcontribs) 22:26, 19 December 2011 (UTC)

Not neutral, not logical, not complete[edit]

End of "Classification" section is biased against the Zn-Cd-Hg-are-not-transition-metals view. (And just what is the electron configuration of Hg+? If it has a full 6d shell, as I think it does IIRC, then the argument used is flawed in the first place.) Also, just because it is convenient to compare the Zn group to the transition metals doesn't mean that they are transition metals. Consider that the article also mentions Ca2+ along with Zn2+ as useful comparisons against transition metal ions; do we ever consider Ca a transition metal? And as for HgF4, it completely disregards Jensen's view that this is an exceptional compound and isn't characteristic of the element and so shouldn't determine the group (so calling the Zn group transition metals is like disregarding 99.999% of their chemistry in favour of 0.001% of it in a compound that is so unstable nobody will actually use it).

Yes, I'm currently high on Jensen ;-). But both views should be represented together, and the article should absolutely not call one of them "incorrect".

There's a related problem with logic in the Lu/Lr-are-group-3 paragraph. Just because La and Ac have exceptional s2f0d1 configurations doesn't make them d-block elements and doesn't make them transition elements. Thorium has electron configuration [Rn]6d27s2, yet no one calls it a transition metal. (Also, Lr's electron configuration isn't [Rn]5f146d17s2, it's [Rn]5f147s27p1, which makes any argument based on similar electron configurations rather weak here.) Double sharp (talk) 08:37, 3 August 2013 (UTC)

P.S. And the article never seems to mention the difference between d-block and transition metal even if you take the Lu/Lr-are-group-3-and-group-12-are-transition-metals-view; being in the d-block is an atomic property whose only requirement is that you have valence electrons in d-subshells, whereas being a transition metal is a chemical property whose requirement is that you show the typical chemistry of a transition metal. Hence, Mt, Ds, and Rg, not having shown any chemistry (it hasn't been tested yet), are not transition metals yet (until such time that experiments are carried out and they are found to behave as expected, of course). (Strictly speaking, since we don't know the electron configurations of anything above Rf, should we really label them in Block (periodic table) as being in the d- and p-blocks?) Double sharp (talk) 08:41, 3 August 2013 (UTC)

P.P.S. This is worse than I thought! At the beginning of the "Classification" section we have the statement that the d-subshell has higher energy than the s-subshell. Sloppy aufbau perhaps? They have about the same energy, and in fact the d-subshell is filled first: Sc has valence electron configuration 3d14s2; Sc+, 3d14s1; Sc2+, 3d14s0; Sc3+, 3d04s0. The additional electron in Sc2+ that Sc3+ does not have goes into 3d, not 4s!!! In fact they all enter 3d, but two get repelled into 4s (energetically worse for them but better for the entire scandium atom). No situation is reversed, as the article may tell you!!! (Also, in divalent and trivalent transition metal ions, there aren't any s electrons, so how can they have higher energy?) Pairs such as 4s/3d, 5s/4d etc. don't always have the first orbital with lower energy than the second, depending on what element you are talking about! (The same occurs for f-block elements, but that's not an issue for this page.) This would be a great article, if it would only explain things correctly... Double sharp (talk) 08:51, 3 August 2013 (UTC)

Elementary textbooks (and some editors) like the 3-12 definition because it is simple for students, but I agree with you that an encyclopedia article should be more neutral and nuanced. For now I have made the language a little more NPOV, removing the "incorrectly" for example. Also I noticed that the article incorrectly cited both Andrews and Jensen as saying that the synthesis of HgF4 shows that Hg is a TM; I checked the sources and this is Andrews' view but Jensen disagrees. Dirac66 (talk) 16:00, 5 August 2013 (UTC)

why on earth is the 4-11 definition given so much prominence[edit]

I should have thought it would be the least prominent! It appears to be mainly a UK thing and is the only one of the three most common ones (3-11, 3-12, 4-11) that is not allowed by IUPAC. IUPAC is flexible on group 12 but always says that either the element must have incomplete d-orbitals or it must form ions that do so. The first point forces group 3 in. Of course there are problems. If we take it literally, uranium is a transition metal but neodymium is not, and neither is lawrencium: probably not how most would define it. But there is no way to read this that excludes Sc and Y. Double sharp (talk) 03:40, 24 December 2015 (UTC)

(P.S. I'm trying not to be biased when I say this, because 4-11 is the definition I was taught.) Double sharp (talk) 06:08, 8 July 2016 (UTC)
I don't think the present article really intends to include a purely 4-11 definition. The paragraph to which I think you refer says The elements of groups 4-11 are generally recognized as transition metals, justified by their typical chemistry, i.e. a large range of complex ions in various oxidation states, coloured complexes, and catalytic properties either as the element or as ions (or both). The elements La–Lu and Ac–Lr and Group 12 attract different definitions from different authors. The phrase generally recognized means that everyone (or nearly everyone) includes the 4-11 elements, but that does not imply that anyone includes only the 4-11 elements. The next sentence means that there is disagreement about which of La-Lu, Ac-Lr and Group 12 should be included, as detailed in the following paragraphs.
The real confusion seems to be due to the fact that Sc and Y are not discussed properly here, but only briefly mentioned in one of the following paragraphs. But on reading the whole article, I think it is clear that Sc and Y are also included by (nearly) everyone. So I am going to explicitly mention Sc and Y as generally recognized in addition to groups 4-11. I hope this clarifies the article. Dirac66 (talk) 22:49, 10 July 2016 (UTC)

Assessment comment[edit]

The comment(s) below were originally left at Talk:Transition metal/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Refering to the following:

"Manganese, for example has two 4s electrons and five 3d electrons, which can be removed. Loss of all of these electrons leads to a +7 oxidation state"

May I recommend: "Manganese has two 4s and 3d electrons which may all be involved in bonding, leading to a +7 oxidation state"

This is consistent with the fact that formal oxidation state is taken as being "the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic".(

I think no-one seriously believes that manganese is present as an ion with a charge of +7 in such compounds. Rather, it may have a charge of +4 and all the remaining electrons be bonding covalently. (talk) 20:26, 13 November 2008 (UTC)

Last edited at 20:26, 13 November 2008 (UTC). Substituted at 09:11, 30 April 2016 (UTC)

Elements literally included by the IUPAC Gold Book definition[edit]

  • Fourth period: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu
  • Fifth period: Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag
  • Sixth period: La, Ce, Gd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg
  • Seventh period: Ac, Th, Pa, U, Np, Cm, Bk, Rf (the following elements do not have experimentally known electron configurations)

In particular, Lr ([Rn]5f147s27p1) cannot be considered a transition metal by this definition as it does not have an incomplete d-subshell, nor can it give rise to cations with such incomplete d-subshells. So if you wanted to follow IUPAC's definition here, the only possible choice for group 3 is for it to have scandium, yttrium, lanthanum, and actinium. Of course, one could argue that this is surely not the spirit of the definition. Double sharp (talk) 12:17, 8 July 2016 (UTC)

Greenwood and Earnshaw's properties of transition metals[edit]

To quote literally from page 905:

The three series of elements arising from the filling of the 3d, 4d, and 5d shells, and situated in the periodic table following the alkaline earth metals, are commonly described as "transition elements", though this term is sometimes also extended to include the lanthanide and actinide (or inner transition) elements. They exhibit a number of characteristic properties which together distinguish them from other groups of elements:

(i) They are all metals and as such are lustrous and deformable and have high electrical and thermal conductivities. In addition, their melting and boiling points tend to be high and they are generally hard and strong.

(ii) Most of them display numerous oxidation states which vary by steps of 1 rather than 2 as is usually the case with those main-group elements which exhibit more than one oxidation state.

(iii) They have an unparalleled propensity for forming coordination complexes with Lewis bases.

I would not take them too literally when it comes to the exclusion of the 6d metals, as they cover actinium together with the rest of group 3 (scandium, yttrium, and lanthanum) and they mention in the chapter on the actinides and transactinides that rutherfordium through copernicium form a fourth, 6d transition series (along, of course, with actinium).

Based on what they go on to cover, they appear to accept all members of group 3 to 12 as transition metals (Sc–Zn; Y–Cd; La, Hf–Hg; Ac, Rf–Cn). They have some more specific remarks on the borderline cases of group 3 and 12.

With regard to group 3, they specifically distance it from the "transition elements proper", while still not disputing their classification as such by (i), writing (p. 948):

In the main, the chemistry of these elements [scandium, yttrium, lanthanum, and actinium] concerns the formation of a predominantly ionic +3 oxidation state arising from the loss of all 3 valence electrons and giving a well-defined cationic aqueous chemistry. Because of this, although each member of this group is the first member of a transition series, its chemistry is largely atypical of the transitio nelements. The variable oxidation states and the marked ability to form coordination compounds with a wide variety of ligands are barely hinted at in this group although materials containing the metals in low oxidation states can be prepared (see p. 949) and a limited organometallic (predominantly cyclopentadienyl) has developed. Differences in chemical behaviour within the group are largely a consequence of the differing sizes of the MIII ions. Scandium, the lightest of these elements, and with the smallest ionic radius, is the least basic and the strongest complexing agent, with properties not unlike those of aluminium. Its aqueous solutions are appreciably hydrolysed and its oxide has some acidic properties. On the hand, lanthanum and actinium (in so far as its properties have been examined) show basic properties approaching those of calcium.

The story is different for group 4, and thereafter remains different. Greenwood and Earnshaw do not refer very much to Hf because it is so similar to Zr. Now for p. 958!

The most important oxidation state in the chemistry of these elements is the group oxidation state of +4. This is too high to be ionic, but zirconium and hafnium, being larger, have oxides which are more basic than that of titanium and give rise to a more extensive and less-hydrolysed aqueous chemistry. In this oxidation state, particularly in the case of the dioxide and tetrachloride, titanium shows many similarities with tin which is of much the same size. A large number of coordination compounds of the MIV metals have been studied and complexes such as [MF6]2− and those with O- and N- donor ligands are especially stable.

Of course, the coordination chemistry is still a little different, as it is not helped very much by synergic π bonding (too few d electrons). Although the MIV (M = Ti, Zr, Hf) ions are much smaller than the preceding MIII ions (M = Sc, Y, La), they are large enough to get to high coordination numbers like 8 for Zr and Hf, which is unusual for the transition metals. Additionally, Zr and Hf do not have aqueous chemistry in states below the maximum because these reduce water. But in general, the rich coordination chemistry of the heavier elements is enough for me to say that unlike Y and La, Zr and Hf are bona fide transition metals by fulfilling criterion (iii). The stories become normal from group 5 onward, where V is similar to Ti (although it prefers +4 to +5), and Nb and Ta anticipate the rich cluster compound chemistry of Mo and W. Already, +5 is much too high an oxidation state to allow any simple ionic salts, even for Nb and Ta.

A bit of weirdness starts to kick in again in group 11, the most ancient royal trio of copper, silver, and gold. They definitely fulfill (i), but only one valence electron is delocalised in their fcc lattice. Furthermore, if we look at the "are there partially-filled d-subshells" definition, silver stands out as its most common oxidation state is Ag+. The only aquo ions in here are Cu+ (not stable), Cu2+, Ag+, and Ag2+ (not stable). (Gold tends to occur as the form of square-planar [AuCl4], as the main route is dissolution of the metal in aqua regia.) Additionally, Cu+ and Ag+ complexes are of rather lower stability than those of Au3+, and the univalent coinage metals show coordination number 2 which is unusual in "transition metals proper (i.e. excluding Zn, Cd, and Hg)" (that word again!). Nevertheless, AgII is common enough that these elements should be considered transition metals.

Last of all is group 12, which never breaches the d subshell under standard conditions (HgF4 doesn't count). Yet there are still some points in their favour, mostly because of (iii): a quote from p. 1206 follows.

In view of the stability of the filled d shell, these elements show few of the characteristic properties of transition metals (p. 905) despite their position in the d block of the periodic table. Thus zinc shows similarities with the main-group metal magnesium, many of their compounds being isomorphous, and it displays the class-a characteristic of complexing readily with O-donor ligands. On the other hand, zinc has a much greater tendency than magnesium to form covalent compounds, and it resembles the transition elements in forming stable complexes not only with O-donor ligands but with N- and S-donor ligands and with halides and CN (see p. 1216) as well. As mentioned above, cadmium is rather similar to zinc and may be regarded as on the class-a/b borderline. However, mercury is undoubtedly class b: it has a much greater tendency to covalency and a preference for N-, P- and S-donor ligands, with which HgII forms complexes whose stability is rarely exceeded by those of any other divalent cation. Compounds of the MII ions of this group are characteristically diamagnetic and those of ZnII, like those of MgII, are colourless. By contrast, many compounds of HgII, and to a lesser extent those of CdII, are highly coloured due to the greater ease of charge transfer from ligands to the more polarizing cations. The increasing polarizing power and covalency of their compounds in the sequence, MgII < ZnII < CdII < HgII, is a reflection of the decreasing nuclear shielding and consequent increasing power of distortion in the sequence: filled p shell < filled d shell < filled f shell.

Hence, we can see that the transition elements may be taken to occupy groups 3–12, with groups 3–4 on the left side and 11–12 on the right side forming preludes and postludes connecting them to the main group. The lanthanides and actinides, coming between groups 3 and 4, similarly form part of this rising of the curtain for the main star of the show, the behaviour we all know and love from, most especially, iron. Double sharp (talk) 12:53, 4 August 2016 (UTC)

Very interesting summary of the views of Greenwood and Earnshaw, who have certainly written one of the leading current textbooks. Next question: what specific changes would you propose to the classification of elements in this Wikipedia article? Dirac66 (talk) 19:31, 6 August 2016 (UTC)
Firstly, we start only by a cold definition of what elements qualify to be considered as transition metals in the lede. We should also do something like what Greenwood and Earnshaw did by talking about some characteristic physical and chemical properties that are common to the vast majority of them. I realise we have this later but this should honestly be in the lede!
Then we can talk about, in the next section, what elements are generally considered under this term, and talk about how there are some borderline cases. Groups 3, 11, and 12 have had a history of not being included, and even group 4 shows some differences. The inclusion of the transactinides also needs a few caveats since the chemistry of Mt, Ds, and Rg has not yet been studied, and even for Ac as well as Lr–Cn it is still poorly known compared with the stable elements (plus Tc) in the first three rows. Additionally the group 3 issue spills over somewhat into here, depending on whether you consider La, Lu, or neither to be a transition metal, and whether this disqualifies them from being considered lanthanides.
I would also like to have descriptive physical and chemical profiles for each of the elements that is normally included, like what we have at post-transition metal (this will overlap for groups 11 and 12). This would be rather long and would have group-by-group summaries. We can skip sections such as history, production, and biological roles, since it is difficult to find a common thread running through all thirty-one of these elements that I usually think about when I hear "transition metal" (Sc, Y, La, Ac; Ti, Zr, Hf; V, Nb, Ta; Cr, Mo, W; Mn, Tc, Re; Fe, Ru, Os; Co, Rh, Ir; Ni, Pd, Pt; Cu, Ag, Au; Zn, Cd, Hg – I think of Rf–Cn predominantly as transactinides rather than transition metals). Anyway Fe dominates the whole block in these fields. (I think we can discuss the lanthanides and actinides all together in one single paragraph, raising arguments for their inclusion and exclusion, and looking at the specific cases of La and Lu, respectively Ac and Lr, at the front and back ends of the series.)
P.S. I think that all the group articles do not need to go into very much detail on sections such as history, production, and biological role. Look at the triad of Fe, Ru, and Os, for instance: Fe utterly dominates the others in these sections, and the only plausible reason to talk about all three together is their scientific properties. Cu, Ag, and Au are the only case when history makes sense to include together, but even then only Cu among this triad has a biological role. Even in alkali metal (which I mostly rewrote), the chemistry sections tend to nicely talk about the whole group (obviously, Fr excepted), while the later sections tend to be split neatly into paragraphs describing each element separately, since Li for example does not generally occur together with Na and K, but rather with Mg due to its similar size. Double sharp (talk) 06:10, 7 August 2016 (UTC)
Two comments:
  • The problem with starting with a cold definition of what elements qualify is to decide whose cold definition to use. There are several out there and Wikipedia is supposed to remain neutral in controversies - see WP:NPOV. If we want a single statement for the lede, it would have to be broad enough to include all the points of view. Perhaps we could say at the outset that there are various definitions which include all or some of Groups 3-12 plus the rare earths (or f-block). Then of course the Classification section can include the various schools of thought, including Greenwood and Earnshaw. Dirac66, 9 August 2016
    • I think you may have misunderstood what I was trying to say, so I'll try to rephrase it. Currently we do start with three cold definitions, which is good. I also like your idea of saying that all of the elements Sc–Zn, Y–Cd, La–Hg, and Ac–Cn have had the term applied to them. But we should IMHO also add some properties that these elements also share – a sort of justification for the definitions, if you will. After all, alkali metal says in its lede "The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1." Can we not have something similar to describe the TMs? Double sharp (talk) 05:56, 30 August 2016 (UTC)
Yes, I will agree that it would be a good idea to also add a statement of the common properties of all (or most) transition metals. Dirac66 (talk) 13:44, 30 August 2016 (UTC)
  • I agree that we do not need to discuss the history, production and biological role of all the elements, which belong in the articles on each element. We should however retain the brief paragraph now at the end of the lede about Charles Bury, which belongs here because it pertains to all the transition metals. Dirac66, 9 August 2016
    • Agreed. There is no sense in talking about individual elements' history, production, and biological roles here, but anything relating to all of them is fair game. Double sharp (talk) 06:01, 30 August 2016 (UTC)

RfC: Colour group 12 as post-transition metals[edit]

I am seeking comments on a proposal to color code the group 12 elements as post-transition metals in the Wikipedia periodic table, rather than transition metals as they are currently color coded.

The RfC can be found here. Sandbh (talk) 23:12, 9 August 2017 (UTC)