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Good article Hassium has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
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Date Process Result
December 31, 2012 Good article nominee Listed
April 9, 2013 Peer review Not reviewed
Current status: Good article
WikiProject Elements (Rated GA-class, Mid-importance)
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This article is part of Wikipedia:WikiProject Elements. Elementbox converted 10:43, 15 July 2005 by Femto (previous revision was that of 20:19, 3 July 2005). 3 July 2005

chemical and physical properties[edit]

To estimate density, a quick calculation can be done given known densities and information from the source cited previously (PhysRevB first principles calculation) to suggest the approximate density of hassium should be 26.2-26.9 g/cm3. Two routes: First, assume 269 amu mass of hassium and divide by volume of a sphere with radius of ~2.99 Rbohr (estimated Wigner−Seitz radius from paper), yields 26.9 g/cm3; Second, assume close packed structure (like hcp of osmium, paper suggests hassium will likely have hcp but fcc is also close in energy), and simply scale the osmium density by the difference in atomic radius and atomic mass such that density = (density of osmium)*(ratio of atomic mass)*(radii ratio)3 = 22.6 g/cm3 * (269/190.3) * (2.80/2.99)3 = 26.23 g/cm3. Any suggestion of a density greater than ~1.4*(density of osmium)=(~32 g/cm3) is unphysical at STP as that would require the atomic radius to shrink from osmium to hassium regardless of crystal structure since osmium is close packed. Jaco0810 (talk) 13:26, 25 March 2015 (UTC)

Why wouldn't it decrease? There's an actinide contraction going on, so it seems possible.
Anyway, regardless of what you think of the cited value, the fact remains that the 40.7 value is cited to multiple reliable sources (some as recent as 2006), whereas your criticism, so far as I know, is not and is therefore original research. If you get it published, we can then include it in the article as an opposing viewpoint, provided of course that enough people agree with you that it wouldn't be undue weight to do so. But until then, we can't. Double sharp (talk) 14:42, 25 March 2015 (UTC)
P.S. After doing some research on the history of this particular prediction: Keller and Burnett predicted 28.6 in 1969, while in the same year Cunningham predicted 35. Fricke et al. reproduced the 28.6 value in 1971, but in a later paper from the same year give both the 28.6 and 35 value(!). Finally in 1974 they give their own prediction of 40.7 as well, and this value seems to be the most commonly re-quoted one. Unfortunately most studies now seem to be more concerned with predicting hassium's chemistry rather than physical properties. It's obvious why really: you can do some actual chemistry with hassium, but good luck getting bulk quantities to find melting point, boiling point, density, etc.! So as late as 2006 this value is still quoted (although often rounded off as just 41). I get the impression there isn't much interest in this particular prediction anymore. A pity really. Double sharp (talk) 14:58, 25 March 2015 (UTC)
You may note that I simply did a calculation of cited values and you are able to check my math. For the given atomic masses of Os and Hs, the radius needs to shrink nearly 8% to get the quoted density in solid state and I read the PhysRevB to show the radius increasing from 2.8 to 2.99 Rbohr. The problem with my calculation is that I mistakenly read the radii ratios as 5d and 6d (hence Os and Hs) whereas the figure is 4d and 6d. Utilizing Ru density etc you get that the density = 12.45 g/cm3*(269/101.07)*(2.99/2.8)^3 = 40.53 g/cm3, I assume they had better knowledge about the radii so that is consistent with the original 40.7 density. The original source that I can find is a publication by Seaborg & Keller in 1986 (earlier work in 1976) and has not been recalculated but re-quoted in the recent literature. Jaco0810 (talk) 19:55, 25 March 2015 (UTC)
By the way, it is not impossible to get an estimated melting point from the quoted calculated modulus and density numbers, so yea, you can get those numbers but it is as you said, no one will have macroscopic amounts of the material so it is academic in most cases.Jaco0810 (talk) 19:55, 25 March 2015 (UTC)
@Jaco0810: Ah, I see. Sorry for jumping on you, but due to problems with verifiability, we try to be very strict on sourcing. Calculations might pass the bar, as long as they are "obvious, correct, and a meaningful reflection of the sources" per Wikipedia policy – I think this corrected calculation, backing up what the sources say instead of giving a new opinion, would pass this bar (although the original one wouldn't, even if it were correct).
Yes, I meant that the 40.7 value was requoted, not recalculated. I should have been clearer!
(I'm incidentally very curious about how to get estimated melting points, as nobody seems to have calculated them for the 6d transition metals! If we have cited values for modulus and density, we could put it in with a note!) Double sharp (talk) 13:07, 26 March 2015 (UTC)

I've deleted the following text, which does not cite a source. If we really want to print speculation, we at least need a source for why this speculation might make sense.

It is predicted that hassium will be the densest element yet known, with a density exceeding two and a half times that of lead. This assumes that a measurable quantity of the element can be made, which is not possible at this time.

Kingdon 04:46, 12 February 2007 (UTC)

I've reverted another edit about the density, which also does not a cite a source. Specifically, the text "estimated 41 g/cm³" in the elementbox and "Hassium is probably the densest element known, with an estimated density of 41 g/cm³." in the article (the latter was also poorly placed - next to the ref tag for the "Chemistry of Hassium" paper, although I saw no mention of density in that paper). If there is a reason to include this in the article, we need a source for the information. See WP:ATT for example. Kingdon 00:08, 21 February 2007 (UTC)

Another question: Are there also predictions about the existence of an octafluoride HsF8? Its lighter homologue Osmium octafluoride is unknown until now, but the Wikipedia article about Meitnerium cites the possible existence of MtF9 (although very carefully), which would be isoelectronic with HsF8. So the existence of HsF8 is at least imaginable... -- (talk) 19:43, 3 November 2013 (UTC)

It's not impossible. The only trouble is that it's cooler for scientists to publish papers speculating about the unknown oxidation state +9 than the known oxidation state +8, and so you see speculation about Mt(IX) but not Hs(VIII)! But spin-orbit coupling effects may destabilize it, just like it does for MtF9 and [MtO4]+ (which is why I added so many caveats as they may or may not be actually feasible or possible), so we might not have HsF8. Additionally the Hs atom is predicted to be even smaller than the Os atom thanks to the actinide contraction, so we may not be able to fit eight F atoms around it (it's at least possible for Os, even though it's not known): similarly for MtF9. Double sharp (talk) 02:33, 4 November 2013 (UTC)


An anon. added this isotope, unref'd, w a half life of 12m. Just want to be sure it's not vandalism. kwami (talk) 03:40, 5 April 2008 (UTC)

No, it's not "un"ref'd. Who unrefd and where?! Why don't you do the proper research before you ignorantly obstruct these pages? -lysdexia 07:51, 5 April 2008 (UTC) —Preceding unsigned comment added by (talk)
There was no reference. I found one for 16.5 min. I don't have time to follow up every anonymous edit tweaking numbers to see if it's vandalism, which is why I added a comment here rather than simply reverting. kwami (talk) 07:54, 5 April 2008 (UTC)
The ref is in Wikipedia's data page for isotopes, and its talk page. There's also Google. —Preceding unsigned comment added by (talk) 08:02, 5 April 2008 (UTC)
@kwami: Could you add the reference for 16.5 min you mention? In the article, there is no reference given for it, except a "see ununquadium" - and that article does not mention the isotope in question. --Roentgenium111 (talk) 18:15, 11 April 2010 (UTC)
Ah, is it ? Though they don't seem to mention this value as a half-life, only as the decay time for a single nucleus. --Roentgenium111 (talk) 18:46, 11 April 2010 (UTC)
Since the 16.5 min figure is for a single event, the estimated half-life for 277Hs would be 16.5 ln 2 ≈ 11.4 min, naturally with large error bars. However, it seems that this data was actually for a metastable isomer, and not the ground state (which has been listed as having a half-life of 2 s). Double sharp (talk) 14:04, 1 May 2014 (UTC)
Right. But Isotopes of hassium considers this isomer unconfirmed and does not even list it in its table (instead another shorter-lived isomer is given). I think we should do the same here and remove it at least from the infobox and the equally prominent lead. --Roentgenium111 (talk) 22:07, 7 May 2014 (UTC)

GA Review[edit]

This review is transcluded from Talk:Hassium/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Gilderien (talk · contribs) 01:14, 23 December 2012 (UTC)

The article on first reading is a well-written and relatively understandable. It may be difficult to understand for a reader with no previous knowledge of nuclear synthesis or transition chemistry but this is probably inevitable for an article of this type. More images would be useful, but all the current ones are either free or with an acceptable fair use rationale. There appears to be no major problems, and certainly not any quick-fail criteria, however there were one or two problems:

  • I added another picture. I don't think there are many other suitable places, though. Double sharp (talk) 12:16, 25 December 2012 (UTC)
  • Reference 23 is dead.
  • Reference 27 is not sufficient in the case of the link being lost.
  • The majority of the Natural Occurence paragraph is speculation and thus needs to be cited to a reliable scientific source.
    • Almost all of it (from "More recently, it was hypothesized..." to "...theoretically possible, but highly unlikely") is referenced by reference 40 (a journal article). Is the way I formatted it OK? Double sharp (talk) 14:42, 23 December 2012 (UTC)
      • Probably yes, but I added the reference to other sentences that appeared to be speculation and thus needed to be sourced.--Gilderien Chat|List of good deeds 17:39, 23 December 2012 (UTC)
  • Almost none of what it referenced to Nature's Building Blocks appears in my copy, however it is the 2002 edition and so the Hassium section presumably has been updated? Does it now have its own section and is not merely covered with the rest of the transfermium elements?
    • Yes, it does. Now every element up to element 127 has its own section in Nature's Building Blocks. Double sharp (talk) 14:38, 23 December 2012 (UTC)
  • One citation is not sufficient for the 270Hs: prospects for a deformed doubly magic nucleus paragraph - it may support the whole section, but as the full text is not freely available this must be specified.
    •  Done Added a few more refs. Double sharp (talk) 03:00, 29 December 2012 (UTC)

--Gilderien Chat|List of good deeds 13:00, 23 December 2012 (UTC)

  • As per the previous comment, the last two paragraphs on gas phase chemistry require some more citations, as does the physical and atomic paragraph, particularly regarding the claim that it is twice as dense as the densest element.--Gilderien Chat|List of good deeds 12:03, 29 December 2012 (UTC)

GA review – see WP:WIAGA for criteria

  1. Is it reasonably well written?
    A. Prose quality:
    B. MoS compliance:
  2. Is it factually accurate and verifiable?
    A. References to sources:
    B. Citation of reliable sources where necessary:
    C. No original research:
  3. Is it broad in its coverage?
    A. Major aspects:
    B. Focused:
  4. Is it neutral?
    Fair representation without bias:
  5. Is it stable?
    No edit wars, etc:
  6. Does it contain images to illustrate the topic?
    A. Images are copyright tagged, and non-free images have fair use rationales:
    B. Images are provided where possible and appropriate, with suitable captions:
  7. Overall:
    Pass or Fail:

Congratulations, we have a new Good Article. --Gilderien Chat|List of good deeds 19:28, 31 December 2012 (UTC)


I just stumbled upon a text that said the molybdenite where sergenium was claimed to be found came from the peninsula of Çeleken, in Turkmenistan. A quick check shows there are molybdenite mines there. Still (former Soviet) Central Asia, not much changes, have no "official" ref to support my claim; even though as for me, I can easily imagine a Westerner confusing Kazakhstan and Turkmenistan (although maybe it's because of Hollywood movies, whose producers have very serious geography problems if it's east from Germany).

Just sayin'.--R8R Gtrs (talk) 19:28, 14 June 2013 (UTC)

Also see (Google Translate it). Request at ref desk if interested. And see (supports Kazakhstan)--R8R Gtrs (talk) 19:35, 14 June 2013 (UTC)
Kulakov, V. M. (1970). "Has element 108 been discovered?". Soviet Atomic Energy. 29 (5): 1166. doi:10.1007/BF01666716.  should be included and the Cherdyntsev, V.V.; Mikhailov, V.F. (1963). "THE PRIMORDIAL TRANSURANIUM ISOTOPE IN NATURE". Geokhimiya (U.S.S.R.). 1: 3–14. 
Thanks! Will read it and improve the article with it. (well, when I have time) Double sharp (talk) 16:42, 6 July 2013 (UTC)

Hmm, 2 vs. 1 on Kazakhstan, the 1 is not a published book or journal article; I'll use Kazakhstan for now, though what you say is very believeable... Double sharp (talk) 14:30, 10 August 2013 (UTC)

How Dubna first got off with their lead-based reactions (to add prior to FAC)[edit]

--R8R (talk) 22:40, 1 March 2017 (UTC)