Talk:Astatine/Archive 2

Archive 1

Archive 2

Colour

The article currently reads: 'Astatine fits the trend well, being a black solid.[8]'

Unfortunately, this is not so. Reference [8] is erroneous. Macroscopic (visible) quantities of astatine have not yet been prepared. Neither has there been, to my knowledge, any theoretical study in the literature as to the predicted colour of astatine. Sandbh (talk) 10:29, 26 March 2012 (UTC)

Couldn't this be predicted from spectra? Allens (talk | contribs) 12:11, 26 March 2012 (UTC)

Look. You are right about the reference. But if you know why X2 get darker with the atomic number, then you can expect At2 should be black. Therefore, I decided it was OK to find a lame ref. Now, I know astatine may be not At2. You are free to remove this.

Spectra? Well, yes. The color of the element/compound is the opposite to the color it absorbs. For example, iodine absorbs yellow, so (almost) unbound I2 molecules are violet.R8R Gtrs (talk) 13:27, 26 March 2012 (UTC)

I found some other references to solid astatine either being black or having a metallic appearance. None of these references cite original sources. The earliest black reference is from 1960! One of the later refs notes that solid astatine has never been observed and then suggests that it is logical to conclude that it would most likely be black. I think what is happening is that, in some cases, plausible extrapolations based on the colour of the lighter halogens are being presented as statements, without any explanation that they are extrapolations. So the result is a mixture of information, with some references saying the colour of astatine is unknown, and others noting—either as statements or extrapolations—that astatine either has, or probably has, a black or metallic appearance. This diversity of information about astatine is interesting. I'll see if I can post an edit about all of this, including current and new references. Sandbh (talk) 06:58, 29 March 2012 (UTC)

I believe that, rather than wikipedia recirculating speculations, it would be MUCH more valuable for it to state "As yet, no sample of astatine large enough to be viewable with the naked eye have ever been prepared. As such, the colour of bulk astatine remains a subject for speculation" or something like that. Such a statement is MUCH more informative to the reader, it rams home the point that astitine barely occurs in nature and has never been obtained in macroscopic quantities.--feline1 (talk) 13:36, 29 March 2012 (UTC)

Done Sandbh (talk) 10:59, 31 March 2012 (UTC)

The metalloid article has some interesting further info re astatine's nonmetal/metalloid/metal status. Not sure how much (more), if any, of it (that isn't already present) should be in this article. I do believe it has some references that aren't in this article. Allens (talk | contribs) 13:02, 9 April 2012 (UTC)

Oh. And another section of that article discusses periodic table trends and metalloids (on that basis, astatine's a metalloid, as far as I can tell). Currently, that's a citation needed area; I don't know which of the various citations would be useful, not having the texts in question, however... Allens (talk | contribs) 13:15, 9 April 2012 (UTC)

One interesting pieces of information from the metalloid article is that astatine has a relatively large band gap energy, more similar to nonmetals than to metals; IIRC, doesn't that indicate that it wouldn't shine like a metal? Allens (talk | contribs) 13:18, 9 April 2012 (UTC)

In theory, we could limit the addition new info from there not very strictly, I guess (since so little is actually known). There's a very short article saying there are no period 6 "semimetals." (here) And much of such. Also, about band gap energy. If 0.7 eV is a correct figure, then it could shine: germanium (band gap of 0.67 eV) and silicon (>1 eV) shine (if the shine is actually dependent on this). This figure is associated with typical semiconductors. Also, when E_g=0 or is even slightly lower, it indicates the element is still a metalloid (per Russian wiki), so on this basis astatine is probably is metalloid.--R8R Gtrs (talk) 07:57, 10 April 2012 (UTC)

Yes. This is good. Consider iodine, which has a bandgap of ~1.3 eV. Steudel (1977, p. 240) says of iodine that: '...considerable orbital overlap must exist, to form intermolecular, many-center...[sigma] bonds, spread through the layer and populated with delocalized electrons, reflected in the properties of iodine (lustre, color, moderate electrical conductivity).' The appearance of iodine is described as 'Lustrous metallic gray, violet as a gas'. The remarkable picture backs up the metallic appearance---not to be confused with the violet vapours. Based on a reducing halogen band gap with increasing atomic number, a band gap of 0.7 eV for At is quite plausible, as would be a metallic appearance per iodine. Astatine might instead form a metallic structure either due to relativistic effects like in Po, or all by itself due to Goldhammer-Herzfeld criterion ratio being >=1, in which case hello metallic appearance. Sandbh (talk) 10:37, 11 April 2012 (UTC)

• Steudel R 1977, Chemistry of the non-metals: With an introduction to atomic structure and chemical bonding, Walter de Gruyter, Berlin

With hydrogen

This subsection currently says: "It [AtH/HAt] is easily oxidized: upon the addition of nitric acid (in which astatine is said to exist as At(0) or At⁺) and silver(I), astatine precipitates only partially as silver(I) astatide (AgAt), or not at all. Iodine, in contrast, precipitates readily as silver(I) iodide." Allens (talk) then asked, "Why does not precipitating well indicate being easily oxidized?"

The relevant extract from Wiberg 2001 (p. 423) is: 'Because hydrogen astatide is readily oxidized, the astatide ion can only be partially precipitated as AgAt after acidification with nitric acid (oxidation) and addition of Ag⁺ ions.' As I understand it, astatine does not precipiate well as AgAt since upon being acidified by nitric acid any or most astatide (At^–) ions, which might otherwise be available, are oxidized to At(0) or At⁺. Whereas, iodine, for example, would still be present in the form of dilute hydroiodic acid (H⁺I^–). This is on the basis that the hydrogen halides become less easy to oxidize with reducing atomic number. Hence not precipating well is associated with easy oxidizability. Sandbh (talk) 13:31, 16 April 2012 (UTC)

I've attempted to clarify this, hopefully without doing too much synthesis... Allens (talk | contribs) 14:07, 16 April 2012 (UTC)

Electronegativity

Does anyone happen to have (free) access to the following and could post any listing of electronegativities or similar information that it gives?

• Dolg, M; Kuchle, W; Stoll, H; Preuss, H; Schwerdtfeger, P (1991). "Ab Initio pseudopotentials for Hg to Rn: II. Molecular calculations on the hydrides of Hg to At and the fluorides of Rn". Molecular Physics. 74 (6): 1265–1285. doi:10.1080/00268979100102951.

It is where the book:

• Barysz, Maria (2010). Relativistic Methods for Chemists. Springer. p. 79. ISBN 978-1-4020-9974-8.

is getting its info on Astatine's electronegativity. I'm wondering for the following two reasons:

1. The latter book is not nearly as clear as one would like on that astatine's electronegativity is below that of hydrogen's.
2. I'd like to be able to get a set of electronegativities, not just for astatine, so as to update more of Electronegativities of the elements (data page) - otherwise, I'd be left putting in an additional reference column for one element, which is inefficient.

Thanks! Allens (talk | contribs) 14:42, 4 April 2012 (UTC)

Dolg et al. do not list any ENs. They only note in passing that in AtH the negative charge is thought to be on the H atom. A similar observation is made by Saue T, Faegir K & Gropen O 1996, 'Relativistic effects on the bonding of heavy and superheavy hydrogen halides', Chemical Physics Letters, 263 (360–366). ENs are not discussed in that article either. Probably the best that could be said is that the EN of At is commonly taken to have the same value as H, however in HAt the negative charge is thought to be on the H atom. And that, consistent with this, it is interesting to note that the EN of At in the Allred-Rochow scale (1.9) is less than that of H (2.2). Sandbh (talk) 13:13, 5 April 2012 (UTC)

Something like this(?):

The element is often said to have an electronegativity of 2.2 (Pauling scale), since this is stated in Pauling's work.[13] This is lower than that of iodine (2.5 in the original work and 2.66 now)[14] and the same as that of hydrogen. However, in [hydrogen astatide] (HAt) the negative charge is thought to be on the hydrogen atom, implying that this compound should be referred to as astatine hydride.[refs per above] Consistent with this finding, the electronegativity of astatine in the Allred-Rochow scale (1.9) is less than that of hydrogen (2.2).[WEL][Note] Astatine sublimes less readily than iodine, with a lower vapor pressure;[clarification needed] it also dissolves in water better than iodine.[2]

Note: The algorithm used to generate the Allred-Rochow scale fails in the case of hydrogen, since it provides a value that is close to that of oxygen (3.5). Hydrogen is instead assigned a value of 2.2. Despite this shortcoming, the Allred-Rochow scale has achieved a relatively high degree of acceptance. [Smith 1990, p. 135]

Smith DW 1990, Inorganic substances: A prelude to the study of descriptive inorganic chemistry, Cambridge University, Cambridge, ISBN 0-521-33738-0

Sandbh (talk) 00:18, 6 April 2012 (UTC)

Looks good; what's the [WEL] reference? Allens (talk | contribs) 00:28, 6 April 2012 (UTC)

Well, (no pun intended) I couldn't find any Allred-Rochow values on Wikipedia (odd, that) so I thought a link to the relevant Webelements page would do Sandbh (talk) 03:40, 6 April 2012 (UTC)

Two references mentioned above say the negative charge "is thought to be" on the H atom in HAt. Does either mention WHY it is thought to be on H? Dirac66 (talk) 01:30, 6 April 2012 (UTC)

No, neither mention why explicitly or clearly, although all may not be lost. They both discuss such things as relativistic dynamics and spin–orbit interaction. They both use 'traditional tools of quantum mechanics' to predict e.g. bond lengths, disassociation energies, vibrational frequencies and dipole moments in HAt or AtH. For example, Saue et al. say, 'The dipole moment is calculated to be 0.06 D with the negative charge on hydrogen, indicating covalent bonding'. It is quite interesting to note that in Dolg et al., the negative charge is listed as being on the H atom, in both the nonrelativistic(!) and relativistic cases. They in fact say that, '...for a proper discussion of relativistic effects it is necessary to carry out both nonrelativistic and quasirelativistic calculations'. It is pertinent to note that neither of the three refs in question say anything about implications for astatine EN. There is another ref in J. Chem. Ed, vol. 82, no. 11, 2005, by Thayer (pp.1721) who also notes the negative pole is predicted to be on hydrogen, and he adds an exclamation mark to this statement, implying astonishment I guess. Perhaps the reference to the Allred-Rochow scale would be better worded as, 'In this context it is interesting to note that the electronegativity of astatine in the Allred-Rochow scale (1.9) is less than that of hydrogen (2.2).[WEL][Note] Sandbh (talk) 05:55, 6 April 2012 (UTC)

Thanks. Actually this does answer my question, since I meant WHY in the sense of "what is the evidence", rather than "what is the physical reason" which is a much harder question. We can mention in the article that quantum chemical calculations (both relativistic and not) indicate a dipole of 0.06 D with the negative charge on H, suggesting a lower EN for At than for H, with the references of course. This should replace the statement that "experiments have shown that astatine's actual electronegativity is slightly less than that of hydrogen", which is incorrect since there are in fact no experimental data. Dirac66 (talk) 15:20, 6 April 2012 (UTC)

OK. I'll post an edit along the lines of my second proposed form of words. I'm somewhat reluctant to say that these papers actually suggest a lower EN for At, since none do so, but I'd be happy to add something about At's EN in the Allred-Rochow scale, and simply leave it as a contextual observation. Sandbh (talk) 02:41, 7 April 2012 (UTC)

Yes, that would reflect the papers more accurately. Dirac66 (talk) 03:00, 7 April 2012 (UTC)

May I have a word, too? I agree with the decision. Only almost until I clear one point. Electronegativity. Doesn't H charged negatively in HAt denote the greater EN for H? I just read the electronegativity article. It says only EN diff (Pauling) can be measured; the electronegative one of the two compared is guessed by "intuition" (read the text). Doesn't this mean, since in HAt H attracts electrons more strongly, it is the electronegative one? If so, this should also be reflected somehow--R8R Gtrs (talk) 13:06, 7 April 2012 (UTC)

The statement about chemical intuition in the electronegativity article applies to the original Pauling method using dissociation energies, which has a square root in the formula so that the sign is undetermined. However if a more modern experimental or computational method shows that the negative charge is on H, that implies that H is more electronegative. At least this would be true if the negative charge were large enough to be certain of the sign. For a dipole as small as 0.06 D the sign is not too reliable and should be treated as only a suggestion. Dirac66 (talk) 18:08, 7 April 2012 (UTC)

Then I only have to clear why there IS an "uncertainty level" 0.06 D falls into, and I'm done with questions here--R8R Gtrs (talk) 14:23, 8 April 2012 (UTC)

0.06 D is the computed value of the dipole, not the uncertainty. The uncertainty depends on the quantum chemical method used and I don't know how large it is. But intuitively 0.06 D is so small that I expect it to be smaller than the uncertainty so that the sign is probably uncertain. If this is true, then all we can really say is that EN(At) is very close to EN(H), without knowing which is larger. Dirac66 (talk) 14:37, 8 April 2012 (UTC)

In other words, it's likely any reasonable confidence interval includes 0. I'm thinking something like "While astatine is frequently said to have an electronegativity the same as hydrogen's, 2.2 (Pauling scale), some calculations indicate that it may actually be slightly less than hydrogen's. If so, then [material about astatide, etc]". That's a first draft, and rough - something needs to be said about people going from Pauling's work. Allens (talk | contribs) 18:17, 8 April 2012 (UTC)

Oh. And perhaps the infobox should have ~2.2 or c. 2.2 as the Pauling-scale electronegativity? Allens (talk | contribs) 18:25, 8 April 2012 (UTC)

I was actually asking why you think 0.06 D is too little to imply the sign. Lurked. Not easily, but formulated an understanding. Seem to know. Question withdrawn---R8R Gtrs (talk) 20:24, 8 April 2012 (UTC)

I initially supported a proposal to list EN(At) as < 2.2 or somesuch but, upon reflection, I think this may be a step too far. The papers in question only talk about a prediction that the negative charge would be on the H atom, and that this compound would therefore be better called a hydride, rather than an astatide. None of them actually had anything to say about EN(At) which, in the literature, is always listed as 2.2 (revised Pauling). Curiously, I just noticed that Maddock (1956, p. 1076; ref details in main article) says that the polarization of the astatine hydride molecule was discussed in Clark CHD 1936, Proc. Leeds. Phil. Soc. 3, 208–17 (Proceedings of the Leeds Philosophical and Literary Society. Scientific section). It could take a while to hunt that one down, although there may be an entry for it in Chemical Abstracts vol. 30, entry 4760. 1936? Very strange. Sandbh (talk) 05:20, 9 April 2012 (UTC)

We should not go beyond what is actually known, which for astatine is very little. Anything written in 1936 must be a periodic-table extrapolation, since astatine had not yet been discovered then. And most of what has been written since seems to be extrapolated also. I would just say 2.2 (approx.) and delete the nomenclature discussion (astatide vs. hydride). Dirac66 (talk) 11:13, 9 April 2012 (UTC)

Even though "approx" is not in the literature yet astatide v. hydride is? Sandbh (talk) 11:43, 9 April 2012 (UTC)

"Some authors imply" should be enough. This is sweet, we could mention it without labeling this "the absolute and undisputed truth." Also, it seems to me that the previous Char discussion about EN(At) (mentioning both old and new). EN(At) stated everywhere is an approximation. None revised it, unlike those of the stable elements. Francium has a more notable (but similar enough) story.--R8R Gtrs (talk) 11:23, 17 April 2012 (UTC)

AtI - heaviest interhalogen?

What about AtI⁻
₂? Or does "interhalogen" not count ions? Allens (talk | contribs) 04:58, 15 April 2012 (UTC)

Yeah, interhalogen refers to the neutral compounds. I don't even know if there's a source for this anion.--Jasper Deng (talk) 05:10, 15 April 2012 (UTC)

There's no and won't be any because this is a lie. IBr5 is way heavier.--R8R Gtrs (talk) 13:05, 16 April 2012 (UTC)

I've corrected it in this and the interhalogen article (as the heaviest known two-atom interhalogen). IBr₅ needs adding to the interhalogen article, if you can locate a reference for it. Allens (talk | contribs) 13:56, 16 April 2012 (UTC)

I've never known any poly-atomic interhalogens that didn't have Cl or F as the peripheral atoms.--Jasper Deng (talk) 17:07, 16 April 2012 (UTC)

A few Google snippets: one and two.--R8R Gtrs (talk) 11:15, 17 April 2012 (UTC)

I've added IBr₅ to the interhalogen article, with 3 refs from Google Books. There's some disagreement over its color, incidentally. Allens (talk | contribs) 22:48, 17 April 2012 (UTC)

Seems fine: good job. The disagreement over color is not novel: a few rarely seen compounds have analogous ones. (Example-- HTcO₄)--R8R Gtrs (talk) 16:44, 18 April 2012 (UTC)

Thanks! I have some suspicion that the colored forms are due to the presence of unreacted iodine or bromide in the older synthesis method(s). It appears that it's currently not synthesized deliberately very much, but shows up in industrial waste, making its color rather hard to pin down in the usual form seen... Allens (talk | contribs) 17:05, 18 April 2012 (UTC)

The disagreement definitely goes from the impurities. (Impurities matter: <1% of the dioxide in thorium metal leads to lowering the m.p. for a few hundreds kelvins) Never explored the topic, so didn't know about wastes. (However, it seems weird if science literature cited the IBr5 wastes color as the true IBr5 color)--R8R Gtrs (talk) 17:17, 18 April 2012 (UTC)

(We should probably move this discussion to the Talk:Interhalogen page.) The difficulty comes from the scarcity (at least in Google Books) of modern info on IBr5. It used to be used vs diptheria, so there's lots of stuff from 1909 and before on it. Of the two modern references, one just says "crystalline solid" and one (on wastes) says "colorless crystals", unstable on heating, very toxic, and that it's a byproduct of some syntheses. The one from 1909 goes into much, much more detail, including synthesis, it giving off bromine vapors if heated sufficiently, etc. That one also claims that it's liquid at anything above 4C, which may be a matter of the presence of iodine, bromine, and/or water. Except... normally crystallization drives out impurities, right? Allens (talk | contribs) 22:05, 18 April 2012 (UTC)

IBr5 probably hasn't been synthesized, to date. It isn't mentioned in any of the 'majors' (Greenwood & Earnshaw; Cotton & Wilkinson; Wiberg). Sharpe (1956), writing in (the) Supplement to Mellor's comprehensive treatise on inorganic and theoretical chemistry, Supplement II, Part 1, (F, Cl, Br, I, At), p. 742, says: 'The conclusion that there is only one bromide of iodine, IBr (Mellor, II, 122), remains unchallenged.' (Mellor II is available via the Internet archive.) Even so it would be worth making some mention of this situation. Sandbh (talk) 11:24, 19 April 2012 (UTC)

Unless you'd like to do it, I'll put in that some sources claim it hasn't been synthesized. The two modern references (more modern than Sharpe) and the 1909 one all indicate differently, however. It apparently isn't being deliberately synthesized nowadays... Allens (talk | contribs) 13:01, 19 April 2012 (UTC)

Yes, feel free to do so. I suspect that the two later sources may be erroneous. I cannot find any references to IBr5, more modern than Sharpe, in any journals albeit I haven't looked exhaustively. The descriptions of IBr5 sound like what Mellor attributed them to: either a solid mix of ice and IBr or a liquid mix of IBr and an excess of bromine. As well, whilst chemistry always comes up with surprises, I have a hard time conceiving how Br with an EN of 2.96 could lure five electrons away from I with an EN of 2.66, in order to form IBr5. Mind you I haven't looked closely to see if there are any other XY5 or so compounds with comparably small EN differences, that would discount my skepticism. Sandbh (talk) 02:41, 20 April 2012 (UTC)

Compounds section

Do we need the subheaders? I wrotetried to write a solid text for each section, small enough to go without subheaders and large enough to have the contents and the composition. The subsections are 1 para long, some terribly short alone (but were fine with the others); the section in whole isn't too long. I just thought that someone who would be to read the article wouldn't look for specifically At-O compounds...why the subheaders? (I didn't even like the Char subheaders, don't feel the need)--R8R Gtrs (talk) 17:00, 18 April 2012 (UTC)

Good question; I'll take a look at the current elements FAs to see if they give any hints. Note that it's possible to have headers without them being in the table of contents, via {{TOC limit}}. Allens (talk | contribs) 17:10, 18 April 2012 (UTC)

A look at the highly-radioactive-element FAs indicates that we should probably move the compounds section (probably without subheaders) into the characteristics section, but keep the characteristics subheaders (including "compounds" as a subheader). About the only difficulty that I can see with this is the table of At-including substances used in cancer treatment, etc - they're compounds of At also... Allens (talk | contribs) 21:41, 18 April 2012 (UTC)

Dunno. Think they're irrelevant. Francium's chemistry is only Fr+, not much to tell, so no separate section. Uuo's chemistry hasn't even been tested, no section either. And we've got a story...--R8R Gtrs (talk) 11:01, 20 April 2012 (UTC)

Hrm - before I saw this, I had already altered it. I was also going off of Technetium, also a (radioactive) FA, with more compounds (and level-4 subheaders for them, admittedly); it has +4, +5, and +7 as common states. If you wish, feel free to alter it back... Allens (talk | contribs) 11:15, 20 April 2012 (UTC)

Less subheads is OK although having them there for a while imposed some content and organizational discipline, I thought. Sandbh (talk) 12:10, 20 April 2012 (UTC)

Existence of At(VII)

Some of the recent literature about this is erroneous. Barysz (2010, p. 79) says that this state has not been verified and that earlier claims for AtO₄^– had also not been verified. She cites a 1964 reference. Atkins et al. (2010, p. 421) say the same thing: 'No evidence for At(VIII) has yet been obtained'.

Gmelin (1985, pp. 112, 192–193), however, notes that the formation of the perastatate ion (AtO₄^–) was reported in 1970 and that its synthesis was replicated and confirmed with new evidence in 1978. Greenwood and Earnshaw (2002, p. 886) write that, 'The perastatate ion, AtO₄^–, was first conclusively prepared by VA Khalkin's group in the USSR 1970 using solid XeF₂ in hot NaOH solution at ph ~10.'

• Atkins P, Overton T, Rourke J, Weller M & Armstrong F 2010, Shriver & Atkins' inorganic chemistry, 5th ed., Oxford University Press, Oxford, ISBN 1-4292-1820-7
• Barysz M 2010, Relativistic methods for chemists, Springer
• Gmelin: Kugler HK & Keller C (eds) 1985, Gmelin handbook of inorganic and organometallic chemistry, 8th ed., 'At, Astatine', system no. 8a, Springer-Verlag, Berlin, ISBN 3-540-93516-9
• Greenwood NN & Earnshaw A 2002, Chemistry of the elements, 2nd ed., Butterworth-Heinemann, ISBN 0-7506-3365-4 — Preceding unsigned comment added by Sandbh (talk • contribs) 08:23, 13 April 2012 (UTC)

The Gmelin ref seems good and belieable. (this doesn't explain why Atkins and his colleagues don't believe in At(VII), though)--R8R Gtrs (talk) 16:48, 18 April 2012 (UTC)

Yes, Gmelin is very good.

Atkins et al. are wrong. I would attribute this to (a) astatine being in the backwaters of chemistry; (b) the need to meet commercial publishing deadlines to get the next edition of their book out, in order to maintain sales; (c) the general practice of repeating what other authors say, who are in the same 'publish or be damned' situation; (d) a little bit of professional blinkers---focussing on and accepting what is thought to be known rather than asking why not; and (e) good faith human error.

This doesn't matter much since probably 99+ per cent of what they say is OK however under this business model the 1 per cent zone can be quite risky.

I reckon the same thing has happened with IBr5; and I know of a few other examples. How about Bresica (1975, p. 137) who said that 'transition metals do not form monatomic anions.' Some thirty years earlier, however, Sommer (1943) had reported the preparation of the yellow transparent compound CsAu. This was subsequently shown to consist of caesium cations (+1) and auride anions (–1), although it took some years for this 'surprising' conclusion to be accepted. (Spicer, Sommer & White 1959, p. 61). Or Brown et al. (2009, p. 137): 'the alkali metal ions (group 1A) always have a +1 charge, and therefore the alkali metals always have an oxidation number of +1 in their compounds.' Whereas the synthesis of a crystalline salt of the sodium anion Na^– was reported in 1974 (Dye et al.). Or The Encyclopedia Britannica (2008): 'Fluorine is difficult to isolate from its compounds, and in fact it is impossible to free it by chemical means.' Whereas a purely chemical preparation of diatomic fluorine was achieved in 1986 (Christe). And there is also the Journal of Chemical Education, which lists nearly 30 articles about textbook errors.

I don't think any of this matters that much but it is good to be aware of the phenomenon. It gives rise to the disclaimer in front of many books that says something like, 'all errors are our own and we are happy to have this pointed out to us for correction in future editions' etc Sandbh (talk) 05:22, 21 April 2012 (UTC)

• Brescia F 1975, Fundamentals of chemistry, Academic Press, New York.
• Brown TL, LeMay HE, Bursten BE, Murphy CJ & Woodward P 2009, Chemistry: The Central Science, 11th ed., Pearson Education, NJ.
• Christe KO 1986, 'Chemical synthesis of elemental fluorine', Inorganic Chemistry, vol. 25, no. 21, Oct, pp. 3721–3722.
• Dye JL, Ceraso JM, Tak ML, Barnett BL & Tehan FJ 1974, 'Crystalline salt of the sodium anion (Na^–)', Journal of the American Chemical Society, vol. 96, no. 2, pp. 608–609.
• Sommer AH, 'Alloys of Gold with alkali metals', Nature, vol. 152, p. 215.
• Spicer WE, Sommer AH & White JG 1959, 'Studies of the semiconducting properties of the compound CsAu', Physical Review, vol. 115, no. 1, July 1, pp. 57–62.

Thanks for writing that long piece of text. Everything seems clearer. Know this can be used very carefully only, but it's OK. No questions left and 2+2 finally made 4. Thanks again (no new infos here, just thanks)--R8R Gtrs (talk) 17:10, 21 April 2012 (UTC)

That's great! Thank you for the feedback. Sandbh (talk) 02:40, 22 April 2012 (UTC)

Archive talk page?

This talk page is getting rather long, partially with material that's quite old. I've recently set up archiving for Talk:Joan Pujol Garcia, and propose setting it up for this page. I suggest any thread not touched in 30+ days should be archived, plus a maximum 50,000 bytes on the talk page. (Would people prefer the archive box collapsed or not? It's collapsed on the Talk:Joan Pujol Garcia page, if you want to take a look.) Allens (talk | contribs) 21:15, 19 April 2012 (UTC)

I'd prefer a higher limit of ~90 days, that should be enough to get the talk page below 50kB. --Roentgenium111 (talk) 16:42, 20 April 2012 (UTC)

90 days is fine by me. (That limit is in addition to a limit of 50kB, incidentally. I do not have in mind using the additional limit of 10 threads max that I used on the Talk:Joan Pujol Garcia page.) Allens (talk | contribs) 17:01, 20 April 2012 (UTC)

Well, DoubleSharp seems to have done manual archiving. I'm now going to need to figure out how to integrate the manual archives into the automatic version - probably by de-manually archiving it but tagging that material with an archive-now tag to make sure Cluebot III will go ahead and archive it. (I had been waiting to see if anyone else wanted to comment, but it looks like at least three people want archiving, and nobody objects, so...) Allens (talk | contribs) 17:22, 6 May 2012 (UTC)

Declaring my copyedit done for now - will keep an eye on and be back when the FA discussion starts up

As the subject says, I'm declaring my "official"/GOCE copyediting done for now. I'll keep an eye on the article (like copyediting any responses to my clarification requests) and will be back to help out when the FA discussion begins. Allens (talk | contribs) 16:39, 24 May 2012 (UTC)

Yes, the best now. I'm going to be concentrated on another article (I did say this is a side project, didn't I?), sorry, yet watching and sometimes beating the tags again. Thank you very much for your work, you're a great editor; I hope this really is not a "goodbye thanks." Do hope to see you at FAC. --R8R Gtrs (talk) 17:03, 24 May 2012 (UTC)

I certainly don't intend for it to be a "goodbye thanks" (does the other article need copyediting?); quite welcome, and thanks for your praise! Allens (talk | contribs) 21:08, 24 May 2012 (UTC)

Of course I know you don't. Just hoping it won't change. And one doesn't thank for the truth :) The article (fluorine) I guess could use one, but definitely later, there are things to be done before copyediting. I can inform you once I set it up, so you're to decide if it will be interesting for you.--R8R Gtrs (talk) 18:00, 27 May 2012 (UTC)

Please do! Allens (talk | contribs) 14:25, 28 May 2012 (UTC)

Astatine-oxygen bonds

The following (in a note linked off of "The lower oxidation states are a common starting point for astatine–oxygen bonds") is completely unclear regarding +1 oxidation states with oxygen: "This starting with lower oxidation states, however, does not mean that there are no halogen-based astatine complexes in an oxidation state above +1, as well as that there is no oxygen-based astatine species in the oxidation state of +1." Are there, or aren't there, oxygen-based astatine chemical species with a +1 oxidation state? There's a double negative with "does not mean" and "there is no". And what's the relationship between this and starting with lower oxidation states in compounds with oxygen? And, moreover, saying that astatine-oxygen bonds usually begin with lower oxidation states (lower as in not above +1?) doesn't seem to have any particular relationship with whether or not there are "halogen-based astatine complexes in an oxidation state above +1". Once I know these things, I can rewrite it to be clear(er). Thanks! Allens (talk | contribs) 11:23, 20 April 2012 (UTC)

Fast re:

• Yes, there's a +1 O-based At species: AtO^- with 0 to 2 protons linked to the oxygen. HOAt is an acid, H₂OAt⁺ is "protonated acid" (viewing as a hydronium with one H replaced with At is also fine).
• Yes again, lower as in not above +1. The latter point also makes sense, there's little. Write as you find better, whatever you write will do.--R8R Gtrs (talk) 16:50, 21 April 2012 (UTC)

I've had a go at rewriting this, rather than trying to answer all of the questions individualyl. Easier to do it that way. Now ready for any further refinements. I thought the presentation of Cr₂O₇^2– looked a bit odd; the subscriped 2 and 7 don't line up. Sandbh (talk) 02:47, 22 April 2012 (UTC)

How about Cr
₂O^2–
₇? Double sharp (talk) 08:31, 6 June 2012 (UTC)

The University of California

In 1945 and earlier, the research university of the University of California was the one in Berkeley, and hence saying anything more than University of California is redundant, misleading, and historically anachronistic.
The only other possible campus of the University of California was its southern division in Los Angeles, which was a teaching institution, and not a research univerisity.
These campuses of the University of California did not exist back then:
The ones in Santa Cruz, Santa Barbara, Riverside, Irvine, San Diego (or La Jolla), Modesto, or Davis. The University of California at San Francisco might have existed, but it wasn't called that. The University of California at Los Angeles might have existed, but it was not a high-level research institution like the one in Berkeley was.
The one in San Francisco was just the medical school, dental school, nursing school, and pharmacy school of the campus in Berkeley.
Also note that its official name has been the University of California at Berkley since sometime in the '70s or '80s.
09:11, 10 August 2012 (UTC) — Preceding unsigned comment added by 98.67.106.59 (talk)

Don't see how it's misleading. It helps clarify what is being talked about. And it is true that it was in Berkeley. It's not completely (my edit summary didn't have this word for some reason) in Berkeley now, after all. Double sharp (talk) 12:55, 10 August 2012 (UTC)

newly discovered info

I just read an article on the Phys.Org website that may contain some useful information or sources that could be added to this Wikipedia article. 66.18.219.221 (talk) 16:40, 6 July 2013 (UTC)

Neptunium Series

I am not sure how to interpret this chart of decay products.

Are the times indicated there half-lives? If so, why does Francium have 5 min? The longest half-life I know about is about 20 seconds. Jokem (talk) 00:48, 21 September 2013 (UTC)

Yes, they are half-lives. ²²¹Fr has a 4.9-minute half-life, and ²²²Fr and ²²³Fr are even longer-lived (14.2 min and 22.00 min respectively). Ref: [1] (registration required). Double sharp (talk) 03:25, 21 September 2013 (UTC)

Estimation of physical properties

Following the progression of coloration, the color of Astatine would be darker than black; this points to an explanation of radioactivity as the natural consequence of consistency constraints in the fabric of the universe, where radioactive elements become radioactive by virtue of it being impossible to display the expected physical property because it makes no sense physically speaking. - djb — Preceding unsigned comment added by 64.134.44.153 (talk) 04:38, 7 January 2014 (UTC)

That assumes that At forms diatomic molecules as its most stable allotrope, which is not known for sure to be the case. And also, if your extrapolations produce nonsensical results, then what's more likely: something's wrong with your extrapolation, or with the universe? Double sharp (talk) 05:52, 7 January 2014 (UTC)

The premise of the estimation---that iodine has a black appearance---is also incorrect. Under white light, at room temperature, solid iodine has a silvery metallic appearance. Astatine, being more metallic than iodine, is most likely to have a silvery metallic appearance, or at least a metallic appearance. Sandbh (talk) 09:53, 7 January 2014 (UTC)

I think this extrapolation is using violet gaseous iodine as the colour for iodine, instead of the silvery metallic solid iodine. Double sharp (talk) 12:49, 21 March 2014 (UTC)

(Also, this doesn't really explain why thorium and uranium are radioactive.) Double sharp (talk) 06:06, 19 July 2014 (UTC)

Sourcing

• Some of the numbers in the infobox do not appear to be sourced anywhere
  • These can be found from the link at the bottom of the infobox saying "references". Only when these standard references (yes they are WP pages but all they have are data values from various sources) don't give a value does the infobox state a reference. This is used in most WP articles on elements, see e.g. iron. Double sharp (talk) 05:01, 21 September 2014 (UTC)
• FN1: pages?
• FN3: where does the page range end?
• Some books include locations, others don't
• Be consistent in how you format edition statements
• GBooks links can be truncated
• FN12: publisher?
• FN15: textbook level and type is not part of the title
• FN26:what is the purpose of the duplication here? Nikkimaria (talk) 02:10, 21 September 2014 (UTC)

Okay, I think we're clear here.

• FN22: I need to fix the chapter thing. The |title= causes this, but I still don't know how to fix it properly.--R8R (talk) 13:11, 27 January 2015 (UTC)

The red message "|chapter= ignored" is a bug in {{cite conference}}, introduced in the latest CS1 code change (chapter handling went wrong). The help link says that it is solved in the sandbox (to be applied in next module:CS1 code change). So if you can wait, it will be solved over time. -DePiep (talk) 08:54, 28 January 2015 (UTC)

Okay, I see. So I think I should leave it as is and wait for the bug to be fixed. I'd expect anyone else (including FAC reviewers) to do the same. Thanks.--R8R (talk) 16:49, 30 January 2015 (UTC)

If this is about FN22, see #sourcing section. Or click & read the help-link in the error message (top note there). -DePiep (talk) 11:20, 5 February 2015 (UTC)

Pre-FAC notes

• The article has blocks of text commented out. It think by now, if these are resolved issues the comments should be deleted. If not resolved, they should be fleshed out here on Talk (into article text or into the bin). -DePiep (talk) 08:57, 28 January 2015 (UTC)

  Yes, thank you. I forget about this comment thing quite easily and I shouldn't. It's a good one; I've asked Sandbh to see if he remembers it. If not, I'll work it out somehow.

• In the infobox, half-life "5.41 h" has the h wikilinked. Needed? -DePiep (talk) 09:00, 28 January 2015 (UTC) unlinked

  I guess not. Thanks for delinking it.

Delinked h, y, d, min in all infoboxes. -23:45, 1 February 2015 (UTC)

• {{infobox astatine}} says for ionisation energy: "1st: 899.003 kJ·mol−1" [FN3]. Glancing (not studying) FN3 gives numbers "9.3175(8) eV" and "9.315(12) eV" and other values nearby. -DePiep (talk) 09:20, 28 January 2015 (UTC)

  The kJ mol^-1 and eV values are equal, so this is fine.

Thanks for taking your time. Much appreciated.--R8R (talk) 19:33, 30 January 2015 (UTC)

I had a look at the commented out text in the synthesis section but couldn't see why this was the case. Sandbh (talk) 02:04, 2 February 2015 (UTC)

• Has the formatting of references been carefully checked? I can see inconsistencies and at least one error. Sandbh (talk) 11:29, 2 February 2015 (UTC)

  I am not good at ref formatting, so I can only rely on those {{cite X}} templates. I see every ref uses one of the sort. What is the problem? Is it something about filling those templates in? And what is the error? How does one check and fix it? --R8R (talk) 15:11, 4 February 2015 (UTC)

Let me get back to you on that one. I've only just finished checking the article text. Still to check notes, element boxes, and structure. Will look at references first. Sandbh (talk) 11:32, 5 February 2015 (UTC)

If this is about FN22, see #sourcing section. Or click & read the help-link in the error message (top note there). -DePiep (talk) 11:37, 5 February 2015 (UTC)

Here are the issues with ref formatting for this version of the article:

• General observation: inconsistent use of caps in journal article titles and book titles
• Ref 2. No need to hyperlink the title and the DOI. The latter will do. The "(ACS publications)" after the journal title is not required. A retrieval date is not required.
• 3. A DOI, a PMC and a PMID aren't necessary. A DOI will suffice.
• 4. First names aren't required. Place of publication (pop) is missing.

  I thought pop was not a must, and it's fine to either have all of them or have none?--R8R (talk) 22:35, 8 February 2015 (UTC)

You are right. Pop is optional. Ignore my references to pop. Sandbh (talk) 06:31, 9 February 2015 (UTC)

• 5. Bib code and doi not both required. Doi will do.
• 6. First names nr; pop missing; edition missing
• 7. Inconsistent with ref 4
• 8. First name nr; pop missing
• 9. As above
• 10. First name nr; multiple editors missing; status as editors missing; pop missing

• (intermediate note) I fixed the neptunium decay chain graph (poor → PTM, use standard colors, rm unused keys, rm some font fancying. Let me know of remaining issues. -DePiep (talk) 23:18, 18 February 2015 (UTC)

Please clear this up to me. When quoting, you don't use first names, but you do use initials (not Donohue, Jerry, but Donohue, J.)? Is that right?--R8R (talk) 18:58, 21 February 2015 (UTC)

Simple stuff, and needs to be checked and corrected reference by reference. Sandbh (talk) 10:51, 6 February 2015 (UTC)

• Please have a look at the comments I added to the chemical routes section. This section needs polishing. Sandbh (talk) 11:32, 5 February 2015 (UTC)

  Indeed, they are very reasonable. Thanks for giving it a look, I could've forgotten about that. I found the book that section is based on, so I'll fix it soon.

Astatine is ready for Mt FAC aside from (1) reference formatting; (2) comments in the chemical routes section. Sandbh (talk) 10:53, 8 February 2015 (UTC)

That's good to know :) It's just me being currently busy IRL, busier than I expected before. I am keeping track on stuff, however; I hope I'll get to these on Thursday or so. My original plan was that the FAC would begin around late February, when I have some spare time, and it seems I will meet this schedule.--R8R (talk) 22:28, 8 February 2015 (UTC)

Okay, I've tried to resolve the problems in comments. I've deleted those last sentences because I don't really understand where they come from, I can't find them in the book in the section I cite. Please check if they are resolved. (My poor English back then; not that it's perfect now, but it has improved since then, I think. Some of the words in question, however, are given in technical dictionaries, but I think I found better ones.)--R8R (talk) 22:54, 12 February 2015 (UTC)

I have a couple more edits on the main article. Will then look at your edit above. The refs still need the be checked. If you are hard up for time I can do them next. Sandbh (talk) 03:31, 17 February 2015 (UTC)

I've seen your latest additions. They're great, really. Now this diamond is turning into a brilliant!

Yes, I remember about those. I wasn't able to find time for that, but chances are I'll finally find it on Thursday or Friday, and will generally be available for real input (I'd say this thinking is now more realistic than before). After all, this is a simple task. Time is all I need. And then, I guess, I'll then take another look on it, a final one. After all, writing about SO interactions in ununseptium somehow made me skip these here, and you are right to have mentioned them here. (But let's wait for Thursday first.)--R8R (talk) 20:29, 17 February 2015 (UTC)

This is very good. I think I'm done on the polishing front. On Thu, I hope to checking your edit and then move to ref formating. Sandbh (talk) 06:18, 18 February 2015 (UTC)

R8R Gtrs: your edits good. We're very close now. Only refs to check and maybe look also at wikilinks, checking for duplication and missing ones. Sandbh (talk) 11:29, 19 February 2015 (UTC)

Good. I removed all duplicating links. (A script highlighted them for me, so I'm confident none are missed.) However, a look for missing ones is still needed. I might give it a look later on. Refs are still ahead, and I'm not yet completely free, but more available than before, I'll try to make it during this weekend (which includes Monday).

I rechecked all refs and tidied as I went. Not sure of the reliability of the Webelements one; the Encyclopaedia Britannica one doesn't look like its formatted right; the Emeléus one looks incomplete; and the Krebs ref is poor quality (too many errors in his book). Aside from fixing these and checking for missing links, I was going to ask User:John for a quick look before FAC? Sandbh (talk) 11:23, 22 February 2015 (UTC)

Krebs was reviewed in the Journal of Chemical Education, vol. 84, no. 11, 2007, p. 1767. The reviewer commented, in part: 'Unfortunately this 2nd edition is still riddled with inconsistencies, misunderstandings, and errors and, therefore, is all but useless as a reference guide.' Sandbh (talk) 11:37, 22 February 2015 (UTC)

I'm not so sure about the recent addition of the CsAtI2 info. Later in that section, we say [AtI2]- may be formed. Should we move it there? Or, given the latter, do we need it at all?--R8R (talk) 13:48, 21 February 2015 (UTC)

CsAtI2, as far as I know is the only other metal-astatine compound known, whereas there are none for any of the other polyhalide ions. I tend to think that since it is a solid compound rather than an ion known only in solution, it might be better where it is. Sandbh 11:23, 22 February 2015 (UTC)

Agree. Now fixed. Sandbh (talk) 11:34, 12 March 2015 (UTC)

• Thank you for the ping. I will have a proper look in the next 24 hours. --John (talk) 11:44, 22 February 2015 (UTC)

Hi John. You're too quick for me! Nice to hear from you. Thanks so much for your interest and judicious trimming. Much shorter than metalloid fortunately. Sandbh (talk) 07:09, 23 February 2015 (UTC)

I would just love to say your work is great. I can't write good prose in English (unfortunately, even my grammar isn't always perfect, since I've been lacking language practice lately), but I suppose I can see one. Your improvements are great, since the language has lost some meaningless words and has become clearer. I might be not the person to impress, but I am impressed.--R8R (talk) 14:32, 23 February 2015 (UTC)

I see you have that Soviet book in English; that's great. But it will raise a reference checker's eyebrow, since we heavily use the original version in Russian. The best way to fix this would be to change all those citations to the English version (this is English Wiki, after all), which could be done in a number of ways. Either you fix it, or you can send the book to me (if it's digital), and I/we could do it. I can get to it tomorrow, or on Saturday, or on Sunday, etc., i.e. I finally do have the time (actually not yet, but since tomorrow). I think this little thing is the only thing that separates us from the FAC, not this time until I can get back, not article quality, not anything. Just this little thing :) --R8R (talk) 20:03, 12 March 2015 (UTC)

I got the English translation via an inter-library loan. As you suggested I've changed all citations to the English version. Sandbh (talk) 09:02, 13 March 2015 (UTC)

Great. :) Now we're ready to go.--R8R (talk) 22:40, 13 March 2015 (UTC)

Astatine-214, -215, -216

Those citations were meant to represent refs that don't even mention those are found in nature. (I was not sure how to do it and if that should be done.) I think we should reformat this rather than delete it.--R8R (talk) 09:34, 23 February 2015 (UTC)

Will have another look tonight. Sandbh (talk) 21:09, 23 February 2015 (UTC)

Aside from this one and checking for wiki links, we're done I believe. Sandbh (talk) 21:35, 23 February 2015 (UTC)

Restored, as per edit note. Sandbh (talk) 09:37, 24 February 2015 (UTC)

I'm too sleepy to fix it now, but I will give it a look tomorrow or on Thursday. While At-214 may be the least commonly mentioned, At-216 is now completely left out. It's not too difficult to fix, I just don't have the strength at the very moment.--R8R (talk) 14:41, 24 February 2015 (UTC)

We can fix this by saying 214 and 215 are sometimes not listed due to discrepancies (and errors) in the literature as to the number of naturally occurring isotopes of astatine e.g. some that say, as late as 1989 (Wilson, Stevie, Magee) astatine has no naturally occurring isotopes. Even Wiberg does not list 214. Sandbh (talk) 21:43, 24 February 2015 (UTC)

Fixed. @R8R Gtrs: If you are happy with wikilinks of technical terms then I think you can go and hoist a flag at Mt FAC and see if anyone salutes =:o @DePiep: @YBG: @Double sharp: @John: --- Sandbh (talk) 10:41, 26 February 2015 (UTC)

One can take a look at its mobile view too, from desktop. It could have visual hiccups (though I didn't see one). -DePiep (talk) 13:13, 26 February 2015 (UTC)

A thing of beauty---best summary of astatine I have seen. Sandbh (talk) 05:15, 28 February 2015 (UTC)

Last read

I think everything is fine. I've done a close look at the details just to make sure it's fine (and check term linking), and, after having looked at it one more time, I'm sure it is. These are very minor, they won't delay the FAC. Okay, maybe there are those last two, but they won't take too long. As always, all questions regarding grammar are just questions; the article's prose has been looked at closely, I don't really question it.

I have looked for problems, I found what I think might need revising, and then will try to fix those I can (all of them except grammar). I finally have spare time, I think, so maybe tomorrow.

Chemically, astatine can behave as a halogen (the group including chlorine and fluorine) -- is it important to distinguish the meanings "periodic table column" and "set of elements"?

I think this reads OK as is, for FAC purposes. I did clarify that "group" meant periodic table group.

Metal formation for astatine has also been suggested,[10] and subsequently predicted.[1] -- don't the verbs mean basically the same? okay, maybe not, but it just puzzled me for a couple of seconds.

Fixed.

"clouded by the extremely low concentrations at which astatine experiments have been conducted, and the possibility of reactions with impurities, walls and filters, or radioactivity by-products, and other unwanted nano-scale interactions." -- need to open a grammar book to understand why (and if) this punctuation is correct. Or is it just cited "as is"?

It's a direct quotation, as scrutinized by JChemEd proof readers.

Caesium diiodo astatate(I) -- is spacing IUPAC-consistent?

It seems not so I joined I and At.

neutral or alkaline solution -- needs to be linked. But to what?

I linked the first mention of alkaline solution to Base (chemistry). Don't think a link is needed for neutral.

Oh yeah. :-)

The first claimed discovery of eka-iodine -- is it okay we don't use quotation marks here?

I'd leave them, to be consistent with dakin.

There was another claim in 1937, by the chemist Rajendralal De. -- I feel that this is how I would tell a story to my friends, or in a magazine, but seems a little too familiar. But maybe it's just me?

I find this to be OK when reading about the curious discovery history of elements such as these. Is consistent with rest of section, too.

true identity of dakin is not known -- again, those quotation marks, yes or no?

Leave them.

"the Greek astatos (αστατος) meaning "'unstable'" vs. "the Greek word ἄστατος (ástatos, meaning 'unstable')" -- I would assume the latter is better, but in either case, this should be standardized.

Former is better: English transliteration first, then actual Greek. Fixed.

Applied to infobox. Can not use {{lang-el}} for this. -DePiep (talk) 10:47, 3 March 2015 (UTC)

(those with mass numbers between 207 and 211) -- maybe go with "(astatine-207 to -211)"?

Agree, done.

North and South America combined -- I remember the book said, "the Americas." Is it appropriate to use this term?

N and S combined i.e. the way it is now reads is better.

astatine-214, -215, and -216 result from the triple alpha decay -- nothing wrong here, just saying the new phrasing of this para is good

tx

energetic alpha particles -- I guess we should explain what "energetic means"?

wlink added: high energies

with modern techniques allowing production runs of 2 terabecquerels -- says a 1989 book. (the situation may not have changed, but is it okay anyway?)

1989 is relatively modern, for an element such as astatine. Could you produce any more without it vaporizing?

Not sure we could, but I'm still not sure. 1989 was 25 years ago, after all. I can go with it, since you're saying it's okay, but I suspect a side reader might question that as well if s/he checks what reference supports the statement.

Updated with Zalutsky and Pruszynski (2011). The 1989 ref gave 2000 MBq = 2 GBq rather than 2 TBq. Sandbh (talk) 12:09, 3 March 2015 (UTC)

is set to a value (such as 30 MeV) -- I remember 30 is a random number I picked up. Which is fine, but Wiberg (?) said the usual range is 26--29. Will check this.

Wiberg says 30 MeV. Sandbh (talk) 11:26, 1 March 2015 (UTC)

I checked it, it says 30 was used by the discoverers, but it implies we now use 26--29. But, having given this a second thought, I'm fine with 30.--R8R (talk) 20:01, 2 March 2015 (UTC)

Updated as per Zalutsky and Pruszynski (2011). Sandbh (talk) 12:09, 3 March 2015 (UTC)

Maximum production run of At to date

Zalutsky and Pruszynski (2011) say: "The maximum level of ²¹¹At that was produced was 6.6 GBq…which to the best of our knowledge, is the highest level of ²¹¹At that has been produced to date."

From here, for a given mass X (in grams) of an isotope with atomic mass Y (in g/mol) and a half-life of Z (in s), the amount of radioactivity can be calculated using:

R (in bequerels) = X*A*ln(2)/(Y*Z)

where A = Avogadro's constant, or 6.02214129(27) × 10²³

This can be rearranged to give:

X = R*Y*Z/(A*ln(2))

For 6.6 gigabequerels of At-211 (atomic mass = 211; half-life = 7.21 hours = 25956 s) this looks like:

6.6 x 10⁹ × 211 × 25956/(6.0221412927 × 10²³ × 0.6931)

= 8.66 × 10^–8 or 86.66 × 10^–9 or 86.66 nanograms.

Sandbh (talk) 06:20, 7 March 2015 (UTC)

Separation

Pre-FAC I made a mental note to revisit this section to see if it could be improved, as it didn't flow as well as the rest of the article, especially the chemical routes content. This was originally hidden from the article but restored as we couldn't work out why it had been hidden.

The section concerned was largely based on Lavrukhina and Pozdnyakov, originally published in 1966, and in a 1970 English translation. Lavrukhina and Pozdnyakov are an interesting read but sometimes hard to follow. I don't know if this is an outcome of the way they wrote the original Russian text (in part they seem to assume a lot of pre-knowledge or write indirectly and leave it the reader to work out the implications) or the translation, or both.

After reading Zalutsky and Pruszynski (2011), and some other later references (Gmelin 1986; Larsen, Wieland and Zalutsky 1996; Lindegren, Bäck and Jensen 2001; and two from 2001 and 2014 that didn't make it into the final mix) I concluded that this section could be improved. So I did some restructuring, editing and citation renovating, to sharpen focus, clarity, flow, and currency. This section reads better now IMO. Sandbh (talk) 04:53, 21 March 2015 (UTC)

Density of metallic astatine (speculation)

Density can be derived from the mass of the unit cell divided by its volume. If condensed astatine has an FCC structure then a diagonal face of the unit cell will be 4R long where R = atomic radius. The edge of the unit cell will then be equal to the square root of 0.5*(4R*4R). The predicted covalent radius of At is 1.5 angstrom. For the two FCC metals in the p-block, Al and Pb, covalent radii are 1.21 and 1.46 and the metallic radii are 1.43 and 1.75. The ratios of metallic: covalent radii are 1.18 and 1.20, respectively. Presuming the lead ratio also holds for At (predicted covalent radius = 1.5 angstrom) that yields a metallic radius for the latter of 1.8 angstrom. The edge of the unit cell will then be 5.09 angstrom, giving a unit cell volume of 131.87 cubic angstroms. There are 4 atoms in an FCC unit cell. So the weight of the cell would be 4*210 (i.e. the atomic weight of At) divided by Avogadro's number i.e. 6.0221412*10^23 = 139.48 x 10^(–23) grams. That gives a density of 10.57 grams per cubic centimetre. How does that look? ( I'm not proposing to use this in the article). Sandbh (talk) 12:17, 14 April 2015‎ (UTC)

(If anyone wants a comparison, that's about the density of silver.) Double sharp (talk) 14:05, 14 April 2015 (UTC)

Copy editing the lead

I copy edited the lead to remove inaccuracies, tighten the text, and make it follow the main body of the article more closely.

Re: "Accordingly, it is so rare in nature it can be considered virtually non-existent". I read the cited reference (Anders 1959) but wasn't able to find any support for this assertion.

Re: "the high cost of doing this" i.e. producing astatine. I removed this as an unsupported assertion. The cost of producing astatine is modest and is no more than that of iodine-123, which is widely available. Sandbh (talk) 05:03, 20 June 2015 (UTC)

Viewing with the naked eye

"Elemental astatine has never been viewed because a mass large enough to be seen by the naked eye would be immediately vaporized by its radioactive heating."

Which I suspect would be a really dumb thing to do with the naked (i.e., unprotected) eye from close range, at least if you wanted to keep said eye intact. Perhaps the text should be clarified as "unaided eye", just in case the "sufficient cooling" becomes possible in the future and someone is taking a close look when the cooling system fails and everything goes boom (or flash as it happens; since this hasn't actually happened nobody knows (and I suspect no one wants to know)) and says afterward that well, Wikipedia said it was OK to look at with the naked eye under those circumstances. Daniel Case (talk) 15:27, 25 June 2015 (UTC)

I think its safe to assume that anyone with the kit to pull such a thing off would probably know what they are doing.©Geni (talk) 23:12, 25 June 2015 (UTC)

Don't underestimate the power of human stupidity. Daniel Case (talk) 04:24, 28 June 2015 (UTC)

"[A]t least if you wanted to keep said eye intact"? I think that ought to be "if you want to stay alive, and not create mountains of paperwork for the rest of your lab to explain some changes in the neighbourhood". Double sharp (talk) 08:10, 13 October 2015 (UTC)

solvation energy of the At⁻ anion in water

Link. Double sharp (talk) 13:07, 18 September 2016 (UTC)

The monoatomic metallic At paper

Link. (Would've posted it to the WP Elements links page, but since this wouldn't be very useful outside the At article...) Double sharp (talk) 04:37, 25 September 2016 (UTC)

A, GA Class review

Astatine

The time has come, and this is the first A-class review for our WikiProject. I believe the article suits A1-A4 well, and I don't know what could be done to suit A5. I wish to push it to FAC later, and first undergo this. This article, in some places, is done like the FAC of francium. Any suggestions and opinions are surely welcome.--R8R Gtrs (talk) 09:35, 20 September 2011 (UTC)

Seems good. I don't know what could be done to get a picture; I tried and found nothing. Yankeesrule3 (talk) 01:53, 26 September 2011 (UTC)

Closed as it's long-lasting with no consensus on it--R8R Gtrs (talk) 17:18, 30 October 2011 (UTC)

GA Review

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

Reviewer: Yankeesrule3 (talk · contribs) 15:33, 31 October 2011 (UTC)

I will be reviewing this article, and it is the first article I will be reviewing as an official member of WP:ELEM.

GA review – see WP:WIAGA for criteria

---

1. Is it reasonably well written?

   A. Prose quality:

   B. MoS compliance for lead, layout, words to watch, fiction, and lists:

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:

   No images, so not applicable to this GA review

   B. Images are provided where possible and appropriate, with suitable captions:

   Images of astatine, unfortunately, are virtually nonexistant, and I doubt we will ever get an image for this element. I will let this slide, but if an image ever becomes available, it needs to be inserted into this article ASAP.

7. Overall:

   Pass or Fail:

Characteristics

• 1st para, second sentence: Source for number?

  My OR based on simple laws. I don't insist on the inclusion, removed.--R8R Gtrs (talk) 12:23, 1 November 2011 (UTC)

• 2nd para, first sentence: When you say "it," what are you referring to?

  I thought that that sentence was quite clear; removed, however, in order not to confuse anyone.--R8R Gtrs (talk) 12:23, 1 November 2011 (UTC)

• 3rd para, first sentence: Restates info in 2nd para, last sentence.

  It doesn't actually. The last sentence of the second para says nothing about that it's a solid.--R8R Gtrs (talk) 12:23, 1 November 2011 (UTC)

Other than these three points, seems good

History

• 3rd para, last sentence: Three out of four what?

  Fixed.--R8R Gtrs (talk) 12:23, 1 November 2011 (UTC)

Other than this one point, seems good

Natural Occurrence

• 1st para, second sentence: "This rarity is explained with that..." is a very awkward phrase.

  Fixed--R8R Gtrs (talk) 12:23, 1 November 2011 (UTC)

• 2nd para, last sentence: "...Has a daughter of..." is strange wording.

  Fixed--R8R Gtrs (talk) 12:23, 1 November 2011 (UTC)

Other than these, seems good

---

Many printed and online sources say that the total amount of astatine in the Earth's crust is "probably less than one ounce" or "about one ounce" or the equivalent in metric units ("about 25 grams"). However, no derivation is shown by these sources. Perhaps the originator of this estimate applied the crustal abundance calculation to the whole mass of the Earth, including the core and mantle, which would yield a total of 24 grams in the entire Earth. However, that would still be a questionable figure because the abundance of ancestor isotopes in the whole mass of the Earth is probably quite different from that of the crust.

The book Holleman-Wiberg's Inorganic Chemistry correctly gives a figure of "3·10-24 % by weight" (3 x 10-26) as the crustal abundance and "no more than 45 milligrams" (0.045 gram) as the total amount of astatine in the Earth's crust. A detailed calculation is available at http://ataridogdaze.com/science/As-Earth-crust.html

Gwc100 (talk) 16:50, 22 August 2013 (UTC)

Chemical reactivity and compounds

• 2nd para, second sentence: Sentence seems overly long, could be split into multiple sentences.

  OK, done.--R8R Gtrs (talk) 07:23, 2 November 2011 (UTC)

• 3rd para, second-to-last sentence: Seems overly short, and has non-encyclopedic wording.

  I'm afraid, astatine is not iodine, there's not that much info. Some things known for stable elements compounds are principally unknown for astatine. And I guess if there's more info on the compounds' properties, it'll be very technical and uninteresting (bond lengths, molecular structures, so on. To be honest, I have searched and haven't seen such info yet). This is not a phenomenon: the FA of francium has no Compounds section at all (not because it an alkali metal; its upper neighbor caesium has one). Non-encyclopedic writing is a problem I will not deny, but to be honest, I don't see it. What's exactly wrong? What could I do?

  I have reworded the part "has seen the light". This was what I was talking about. Sorry if I wasn't clear on this, I should have specified the exact words. Yankeesrule3 (talk) 19:08, 2 November 2011 (UTC)

Other than these two points, all is good

Production and uses

This whole section seems good for a GA. It probably would not be OK for a FA, but for a GA it is fine.

Isotopes

Nothing wrong here, probably could get past even an FA review.

Lead

All statements backed up at some point in main body.

As soon as the chemical reactivity and compounds section is fixed, this should pass the GA review! Yankeesrule3 (talk) 22:38, 1 November 2011 (UTC)

I am now ready to pass this GA review for Astatine. Great job on the article! Yankeesrule3 (talk) 19:12, 2 November 2011 (UTC)

Old. -DePiep (talk) 13:33, 24 February 2017 (UTC)

Carbon tetraastatide

The article says "Carbon tetraastatide has been synthesized", but this seems dubious and I can't verify it. According the Chemical Abstracts, there is only one scientific paper mentioning carbon tetraastatide (Journal of Computational Chemistry (1998), 19(13), 1526-1533) but it is just a computational paper. I don't have access to the book by Emsley used as a reference for this statement, so I can't see exactly what is said there. Can someone find what is said there so we can evaluate it? ChemNerd (talk) 13:24, 1 November 2017 (UTC)

I am not the greatest fan of Emsley's book anyway: it contains a lot of statements that are not substantiated anywhere else, and I would like very much to get rid of all use of it as a source (and I regret that I have used it a few times before finding this out). For what it's worth, the sentence there is "Research carried out at the Brookhaven National Laboratory, at Upton, New York on Long Island, has produced some compounds, fleetingly synthesised, confirming that astatine is like iodine in forming hydrogen astatide (HAt), ionic compounds like sodium astatide (NaAt), and covalent compounds like carbon tetraastatide (CAt₄)." Double sharp (talk) 15:23, 1 November 2017 (UTC)

About the phase of Astatine at STP

As the phase at STP is only theorized, I think we should put (predicted) next to the indication of it being solid. — Preceding unsigned comment added by TheÆtherPlayer (talk • contribs) 14:49, 10 November 2017 (UTC)

Theoretical study of adsorption properties of At species on Au

This (September 2017) is interesting, combined with what it could mean for studies of Nh and Ts. Double sharp (talk) 03:35, 6 February 2018 (UTC)

"Astaine" listed at Redirects for discussion

An editor has asked for a discussion to address the redirect Astaine. Please participate in the redirect discussion if you wish to do so. Steel1943 (talk) 19:50, 20 September 2019 (UTC)

"Asstatine" listed at Redirects for discussion

An editor has asked for a discussion to address the redirect Asstatine. Please participate in the redirect discussion if you wish to do so. Steel1943 (talk) 19:50, 20 September 2019 (UTC)

At last, the full Pourbaix diagram of astatine

Page 33. Double sharp (talk) 13:14, 11 April 2021 (UTC)

(Although I admit some scepticism about "At⁺" and "AtO⁺". Based on Gmelin et al., the former seems to be protonated hypoastatous acid H₂OAt⁺, so not quite a solvated cation.) Double sharp (talk) 13:17, 11 April 2021 (UTC)

Per Gmelin suggestion, maybe the latter also is protonated astatous acid [H₂AtO₂]⁺? Double sharp (talk) 15:24, 13 April 2021 (UTC)

"Astateen" listed at Redirects for discussion

A discussion is taking place to address the redirect Astateen. The discussion will occur at Wikipedia:Redirects for discussion/Log/2021 April 21#Astateen until a consensus is reached, and readers of this page are welcome to contribute to the discussion. –LaundryPizza03 (dc̄) 17:49, 21 April 2021 (UTC)

"Astitene" listed at Redirects for discussion

A discussion is taking place to address the redirect Astitene. The discussion will occur at Wikipedia:Redirects for discussion/Log/2021 April 21#Astitene until a consensus is reached, and readers of this page are welcome to contribute to the discussion. –LaundryPizza03 (dc̄) 17:50, 21 April 2021 (UTC)

Bombarding?

Is "bombarding" really a scientific term that can be used at the end of the article, right at the end of the lead, before the subsections? FikaMedHasse (talk) 10:53, 11 November 2021 (UTC)

It's the standard term in this context, yes. DMacks (talk) 11:29, 11 November 2021 (UTC)

Okay, thank you. I just found the phrase a bit comical. FikaMedHasse (talk) 11:37, 12 November 2021 (UTC)

Sometimes science adopts lay-language words and uses interesting shades of meaning or things that sound funny. In this case, an early ref is Enrico Fermi's "Artificial Radioactivity produced by Neutron Bombardment" article from 1934 (doi:10.1098/rspa.1934.0168). List of unusual units of measurement is a good read. DMacks (talk) 16:34, 12 November 2021 (UTC)

More recent papers on At chemistry

One, two, three, four, five. Double sharp (talk) 22:01, 12 November 2022 (UTC)

8 hour half-life vs immediately vaporized

@R8R, Sandbh, and Double sharp: To a layman, these two statements appear to conflict. We say a sample has never been assembled, with vaporization as an explanation, but then we would still have a gaseous sample. Or if by vaporization we mean more than just turn into a gas, then do we mean accelerate the half-life decay?

Onceinawhile (talk) 10:18, 16 September 2023 (UTC)

@Onceinawhile: Once the sample is vaporised, it's been disassembled. Double sharp (talk) 10:20, 16 September 2023 (UTC)

How is that different to being a gas? A sample of Helium is disassembled too. Onceinawhile (talk) 10:23, 16 September 2023 (UTC)

@Onceinawhile: Okay, fair enough. The way I'd think of it in the hypothetical situation (which is probably more or less what the article was going for), you'd have an astatine sample somewhere, and it would vaporise and diffuse through the air (thus disassembling itself) and cause a massive contamination problem. But I suppose we could think about it being done in a vacuum. So, to avoid doubts about the wording, I've changed it to Consequently, a solid sample of the element has never been seen, because any macroscopic specimen would be immediately vaporized by the heat of its radioactivity. Double sharp (talk) 10:28, 16 September 2023 (UTC)

I agree it's important to clarify text so that it is readily understood by all readers. Polyamorph (talk) 10:32, 16 September 2023 (UTC)

(edit conflict) I don't see the conflict. Research is limited because samples are not stable due to its short half-life and radioactive heating. With cooling techniques it might be possible to synthesise in weighable quantities but this is technically challenging. Sure you will obtain a gas, but then there are technical challenges of containing it safely and it will decay rapidly. Polyamorph (talk) 10:28, 16 September 2023 (UTC)

Thank you Double sharp and Polyamorph. It is a great article. It is a pleasure to read the details of those mysterious elements at the bottom of the periodic table that I would wonder about as a child. Onceinawhile (talk) 10:35, 16 September 2023 (UTC)

So the element has a half-life of about 8 hours, and when its atoms decay, they release a lot of energy. The energy is enough to break the bonds holding the atoms together in a solid state, vaporizing them into a gas. The atoms of astatine still exist as a vapor and are still decaying with a half-life of 8 hours. Just the phase of matter has changed. 108.160.120.91 (talk) 18:52, 16 September 2023 (UTC)

Yes, that is correct. Polyamorph (talk) 19:43, 16 September 2023 (UTC)

The shortest-lived element that anyone has seen as a macroscopic solid sample of seems to be radon (half-life 3.82 days). It was seen in 1909 when Gray and Ramsay measured its melting point: they wrote the solid glows with great brilliancy, like a small, steel-blue arc-light. (For obvious reasons I don't think anyone will be eager to repeat this experiment. That seems to have been at least 600 curies of radon, per 10.1002/anie.201803353. And no, that's not a typo for a less terrifying submultiple of a curie.) Double sharp (talk) 15:36, 17 September 2023 (UTC)

Interesting! Gray lived to his 80s, so didnt seem to do him any harm. Ramsey died age 63 of Nasal cancer, which may or may not be related to his radon work. Polyamorph (talk) 19:53, 18 September 2023 (UTC)