Talk:Astatine/Archive 1

Archive 1

Archive 2

Article changed over to new Wikipedia:WikiProject Elements format by maveric149. Elementbox converted 12:37, 10 July 2005 by Femto (previous revision was that of 07:39, 11 June 2005).

Precautions section. Really needed?

Can anyone tell why there is precaution section? I mean, with the element that is so rare that few people have witness with their own eyes its ridiculous. 188.230.132.58 (talk) 07:59, 19 July 2011 (UTC)

Gmelin devotes 15 or so pages on the topic of handling astatine, including, 'Radation risks, health physics and protection' so it would seem reasonable to include a few words along these lines. Sandbh (talk) 10:44, 11 April 2012 (UTC)

Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory - Astatine. Additional text was taken directly from the Elements database 20001107 (via dict.org) and WordNet (r) 1.7 (via dict.org). Data for the table was obtained from the sources listed on the main page and Wikipedia:WikiProject Elements but was reformatted and converted into SI units.

Ionization energy

From the Village Pump

According to your web page, the first ionization energy of astatine is 20KJ/mol. But i have contacted many universities to check if the first ionization energy has been discovered, and so far all of them have denied of the idea. please contact me to tell me where you got your source for this info. My name is Maulik Shah and my email is: <EMAIL ADDRESS REMOVED>

Thanks

The number 20 is much less than the periodic trend set by Cl, Br and I would seem to predict. -Smack 23:53, 5 Jan 2004 (UTC)

I sent this by email, and was attempting to post it to the pump when my network went down. Smack gave his reply before I could do so...

Information on sources for the element tables is at Wikipedia:WikiProject Elements. The ionization energy for astatine came from the following secondary source: http://www.webelements.com/webelements/elements/text/At/ionz.html . WebElements cites their sources here: [1]. I suggest you look up those two references. It seems entirely possible to me that the ionisation energy was estimated numerically, but that the details of this estimation were lost somewhere between the initial publication and the posting on WebElements.com. (Also by email) -- Tim Starling 01:29, Jan 6, 2004 (UTC)

I looked it up in the Gmelin handbook for astatine. It gives a number of references to different calculations that predict the 1st ionization energy as around 9.4eV (about 907 kJ/mol, if I've done the calculation right). It doesn't seem to have yet been experimentally measured. Actually, looking at the webpage referenced about it actually gives it as 920 kJ/mol, I suspect a typo -- DrBob 23:46, 6 Jan 2004 (UTC)

NIST quotes a single determination of the ionization energy, 890±40 kJ/mol, by Finkelnburg, W.; Humbach, W. (1955). "Ionisierungsenergien von Atomen und Atomionen." Naturwiss. 42:35. Physchim62 (talk) 13:47, 23 April 2007 (UTC)

NIST actually quote a figure of 920±40. Gmelin (p. 108) quotes the same NIST figure. Is the template box value of 890±40 kJ·mol−1 a longstanding typo? Sandbh (talk) 13:38, 2 April 2012 (UTC)

Ionization energies of the elements (data page) needs updating, then, or someone's likely to "correct" it back. Allens (talk | contribs) 14:03, 4 April 2012 (UTC)

My mistake: The Gmelin and NIST figures are listed in eV = 887.7±38.59 kJ·mol−1 Sandbh (talk) 22:40, 4 April 2012 (UTC)

Have also corrected Molar ionization energies of the elements and Ionization energies of the elements (data page) Sandbh (talk) 08:29, 5 April 2012 (UTC)

Rarest?

Which element is truly "the rarest naturally occuring element in the world", francium or astatine? I do not know if there is a definite answer, but I believe the wording in one or both of these articles would be appropriate. (I placed this discussion in francium's talk page as well, so be sure to check up on that discussion too.)

According to the guinness book of world records astatine is the rarest naturally occuring element with only an estimated 6 ounces in the entire mass of earth.

So then should we take out the phrase "With the possible exception of francium,"?

Actually, the equilibrium mass of astatine (218At) in the earth crust is about 0,13 g whereas the mass of francium (223Fr) is about 340 g. The claim of the Guinness Book of Records (on 25 g of At in the earth crust) is wrong. --V1adis1av 18:25, 5 May 2006 (UTC)

The article on Lutetium states that this element is "the least abundant of all naturally-occurring elements". Correct me if I'm wrong, but isn't that essentially saying that that's also "the rarest naturally occuring element in the world"? TerraFrost 21:12, 8 July 2006 (UTC)

Not necessarily. You might have more Francium and Astatine in outer space, while a bunch of Lutetium could have accumalated up on Earth. But that's just a possible clause. Don't take anything I say as fact.--198.161.102.118 03:18, 21 September 2006 (UTC)

The nonsense in the lutetium article about being rare has been removed since. Femto 11:20, 21 September 2006 (UTC)

I suggest the longest lived Isotope of Astatine is not necessarily the naturally occurring one. Thus, a shorter lived Isotope might be the naturally occuring one. This is based upon the rule of thumb that shorter half-life = less abundant. It would be nice for someone to put in what the naturally occurring isotope is. How about it?

Inspection of the various decay chains of radioactive heavy elements shows that the isotopes of astatine in these chains are in fact not the longest-lived isotope ²¹⁰At (half-life 8.1 hours), but rather ²¹⁸At (half-life 1.5 seconds), ²¹⁷At (half-life 32 milliseconds), and ²¹⁵At (half-life 0.1 ms). Furthermore, the progenitor of ²¹⁸At is ²³⁸U with an extremely long half-life of 4.468 billion years. As I am not a nuclear physicist, I will wait briefly for possible comment by someone with more knowledge of the subject before integrating this point, in less detail, into the article. It seems that it would also be helpful to mention the extreme rarity of astitine very near the beginning of the article; otherwise the many uncertainties about its characteristics discussed early in the article may seem rather odd to the layman. Piperh 17:20, 13 May 2007 (UTC)

Oh and the answer to the question of the rarest element might just be Technetium. Since it has been found to occur on the earth in extraordinary circumstances. This depends upon what you mean, rarest on earth, or rarest in the universe.

I have never been very convinced by claims of naturally occuring technetium. It would have been formed in the Oklo phenomenon (2 billion years ago), but all of that would have decayed by now. However, due to nuclear power generation, there is probably more available technetium than available rhenium! Physchim62 (talk) 09:23, 21 May 2007 (UTC)

You don't need a nuclear reactor (or an Oklo phenomenon) for spontaneous fission to occur. Spontaneous fission of uranium happens all the time, although very slowly. The reactor just makes it much faster by sustaining a chain reaction.--Itub 08:30, 22 May 2007 (UTC)

In reality, this question cannot be answered by anyone. When we are dealing with such small amounts as 10 ounces or less, it is impossible to know which element is least occurring. It could be any of the elements that have been suggested here. Bonzostar (talk) 16:59, 6 November 2008 (UTC)

The case of Tc, Pm, and the transuranic elements may be more complex, but the ratio of At to Fr can indeed be calculated with good accuracy because they both stem from uranium and all the half-lives and decay pathways are very well known. I haven't done the detailed calculation, but just from looking at the half-lives and probabilities it is apparent that Fr must be much more abundant than At. The ratio implied by the numbers given by V1adis1av above seems plausible to me. --Itub (talk) 09:42, 7 November 2008 (UTC)

Based on the estimate cited at technetium (1 ng/kg U), there should be tonnes of Tc in the earth's crust, ie three or four orders of magnitude more than Fr and six to eight orders of magnitude more that At. Promethium is about as abundant as francium, according to the estimate cited in the article. Physchim62 (talk) 10:05, 7 November 2008 (UTC)

That estimate for technetium seems only to hold for uranium ores (according to the source given for it), not necessarily for low-concentrated uranium in sea-water, soil etc. Counting only the known uranium ores (35 million t of U), one arrives at only 35 g of Tc. So Tc is more common than astatine, but possibly rarer than francium. Does someone have an estimate for the total amount of natural neptunium? This might be a real contender for the rarest element...--Roentgenium111 (talk) 19:12, 28 January 2011 (UTC)

Apparently, Bk is the rarest element that has been detected to occur naturally, although Es might well be rarer. Double sharp (talk) 06:02, 23 September 2012 (UTC)

@V1adis1av, Itub: If you have references/easy calculations handy for the claim that Fr is much more abundant than At, it would be nice if you corrected the Francium and/or this article. Currently they claim 30g of Fr and 25-28g of At, contrary to your claims. --Roentgenium111 (talk) 22:50, 3 April 2011 (UTC)

The claim that 217At is the most common naturally occurring isotope is wrong. There is an error in the accompanying decay chain graphic which shows the half life of 217At as 32.1 Seconds but it is 32ms. The great great...grandfather nuclide 237Np has a half life 2.1e15 longer than 217At; therefore the abundance of 217At must be the reciprocal, or 4.8e-16, at equilibrium (there are no side chains in this decay scheme). As the half life of 237Np is 2.14 million years, none of the decay products of 237Np created artificially in the past century or so are anywhere near equilibrium. But even at equilibrium, there would need to be 4.9e8 metric tons of 237Np to produce 0.23g of 217At (the amount needed to make it the Earth's most abundant isotope of At). There are 1e20g of primordial 238U in the Earth's crust to a depth of 25km which is in equilibrium with its daughters, one of which is 0.23g of 218At. There is no way there are 4.9e8 metric tons of 237Np on the Earth, as 2009 world production was only 60 metric tons (1000 critical masses of about 60kg). Even if this amount of 237Np were produced each year for a century, the amount would still be 5 orders of magnitude too small. An additional minuscule natural source of 237Np is as a decay product from transmutation reactions in U ores. If 4.9e8 metric tons (4.9e14g) of 237Np existed within the 1e20g U in the Earth's crust, it would be found at levels of 5 parts per million in these ores which is certainly not the case. Therefore, 217At cannot be the most common naturally occurring isotope of At. 218At holds that honor even though less than 1/4 gram of it is present in the Earth's crust. 219At, daughter of 235U, is 150 times less abundant than 218At. — Preceding unsigned comment added by 98.203.142.12 (talk) 20:27, 7 March 2012 (UTC) 215At, daughter of 235U, with a half life of only 0.1ms along a tiny 0.00023% branch, is 30 million times less abundant than 218At. — Preceding unsigned comment added by ElementGuy (talk • contribs) 20:51, 7 March 2012 (UTC)

Name

Why is it called Astatine? Jimpartame 11:29, 16 April 2006 (UTC)

From the History section: Greek astatos meaning "unstable", named 1940. No stable isotopes. That's all there seems to be behind it. Femto 12:20, 16 April 2006 (UTC)

Half-life of 210At

The article states a 8.1 hours half-life of ²¹⁰At. However, other sources, including lots of websites and the German Wikipedia, say it's 8.3 hours. Unfortunately, some other websites concur with the 8.1h figure so I am not entirely sure who's right. Does anyone have reliable sources? Aragorn2 15:32, 6 September 2006 (UTC)

All references cited at Talk:Isotopes of astatine say 8.1 h. Femto 17:20, 6 September 2006 (UTC)

The article says "The longest-lived isotope is 210At, which has a half-life of 8.3 hours". So, should I revise it? I think I shall, but feel free to change it back. Andrew Kanode (talk) 20:41, 10 February 2008 (UTC)

Graffiti?

I notice the article has the phrase "Your a pussy faggot" in it, after the discussion of thyroids, however it doesn't show up as editable in the edit this page section. Any help by some wiki guru would be awesome. —The preceding unsigned comment was added by 68.14.185.63 (talk • contribs) 16:55, 27 November 2006.

It was removed 26 Nov 19:51 UTC. You must have had the old version in your browser cache and saw the already fixed version only when you tried to edit. Thanks for noticing anyway! Femto 19:06, 27 November 2006 (UTC)

there some more graffiti at the top: "It will explode if you use viagra." --80.42.61.251 22:51, 2 December 2006 (UTC)

Uses?

Please list some uses.

Astatine, even its most stable isotope (astatine-210, with a half-life approx. 8.1 hours), is too radioactive to have much practical use. Recently, 210At has been proposed to be used in medicine as a potential cancer treatment (technetium-99m has a similar half-life and finds use in medicine), but I know not of how far this has gotten (if someone could update this, it would be greatly appreciated).

Decay?

How does it decay? What are the products? What is emitted? 68.121.160.61 02:21, 27 July 2007 (UTC)

It's found at the bottom of the infobox on the right side. Squids'and'Chips 02:23, 27 July 2007 (UTC)

Thank you! I guess I didn't know how to read it.

Is the half life of the lonest lived astatine isotope 8.1 hours or 8.3 hours (the main article says both). Or is it something else? I think it was Napoleon who said that consistency is the last refuge of fools. Someone here is trying to avoid being foolish maybe.... ? —Preceding unsigned comment added by Ruaken (talk • contribs) 22:07, 26 March 2008 (UTC)

Astatine-211

I was searching Google and came across source 7, a use for At-211, but is difficult to understand. Am I the only one that thinks this? Wii Wiki (talk) 19:31, 10 July 2008 (UTC)

References

• Karlik, Berta; Bernert, Trande (1943). "Das Element 85 in den natürlichen Zerfallsreihen". Zeitschrift für Physik. 123: 51. doi:10.1007/BF01375144. and Karlik, B. (1947). "Unsere heutigen Kenntnisse über das Element 85 (Ekajod)". Monatshefte für Chemie. 77: 348. doi:10.1007/BF00899023. are good refs!--Stone (talk) 21:18, 11 July 2008 (UTC)
• Johnson, G. L.; Leininger, R. F.; Segrè, E. (1949). "Chemical Properties of Astatine. I". The Journal of Chemical Physics. 17: 1. doi:10.1063/1.1747034. is another one.Stone (talk) 05:17, 22 October 2008 (UTC)
• Emeleus, H. J (1987-07). Advances in Inorganic Chemistry. ISBN 9780120236312. {{cite book}}: Check date values in: |date= (help)
• Emeleus, (1964). Advances in Inorganic Chemistry. ISBN 9780120236060.{{cite book}}: CS1 maint: extra punctuation (link)
• Anders, E (1959). "Technetium and Astatine Chemistry". Annual Review of Nuclear Science. 9: 203. doi:10.1146/annurev.ns.09.120159.001223.
• Johnson, G. L.; Leininger, R. F.; Segrè, E. (1949). "Chemical Properties of Astatine. I". The Journal of Chemical Physics. 17: 1. doi:10.1063/1.1747034.

might be good also. --Stone (talk) 09:44, 27 October 2010 (UTC)

Strange "e"

Does anyone else see the letter "e" right below the last external link, "Doc Brown's Chemistry Clinic - Group 7 The Halogens"? — Twas Now ( talk • contribs • e-mail ) 22:36, 9 September 2008 (UTC)

It was caused by an error in one of the templates: I've corrected it now, and (browser caches etc permitting) it should be gone by the time anyone reads this message! Physchim62 (talk) 23:34, 9 September 2008 (UTC)

I thought it might be a template error, but, to be honest, I didn't want to check which one it was. — Twas Now ( talk • contribs • e-mail ) 23:56, 9 September 2008 (UTC)

Image

An image purporting to be that of astatine is on this page but macroscopic quantities have never yet been prepared and probably never will be. Further explanation needs to accompany this image. EmleyMoor (talk) 13:05, 25 November 2008 (UTC)

Naming

It is and will be called astatine, that is a fact. But the last lines say it was called Helvetium, then changed to Anglohelvetium, and it doesn't say who changed it why and when to astatine. I threaten you with moving the page to Anglohelvetium! (half a joke), but the reason and person who changed it to the present astatine should be stated (the best would be sourced, but not nessecarily) --Eu-151 (talk) 18:25, 6 July 2009 (UTC)

Er, "The name Helvetium was chosen by the Swiss chemist Walter Minder, when he announced the discovery of element 85 in 1940, but changed his suggested name to Anglohelvetium in 1942.[9]" clearly says who changed it and cites a ref. It is not required that we analyze his action and divine a reason (or even if a personal decision necessarily has a reason or that anyone's written it down), but if you find a cited explanation that's a nice addition. DMacks (talk) 01:18, 15 July 2009 (UTC)

Uses Really?

Can Astatine really be used for anything? Surely its half life is too short? —Preceding unsigned comment added by 81.149.152.145 (talk) 23:41, 16 July 2009 (UTC)

Late response, but, yes. Stick astatine atoms in carbon nanotubes, attach the tubes to cancer-specific antibodies, and set the complexes loose in a tumor. Alpha particles kill the cells. Astatine's half-life is short enough that the complexes won't spread to healthy parts of the body, but long enough so that they'll stick around long enough to do their job. Also, the resulting bismuth isn't as toxic as other heavy metals, letting the body deal with it.

TL;DR: Treat cancer. 72.178.12.19 (talk) 04:37, 26 October 2009 (UTC)

Second-heaviest halogen?

"It is the second-heaviest of the discovered halogens."
Really? It's uncertain as to whether or not ununseptium is a halogen, so therefore I propose changing the phrase to
"It is the heaviest of all halogens, with the possible expeption of ununseptium."
or something similar. —Preceding unsigned comment added by Haosys (talk • contribs) 18:58, 17 August 2010 (UTC)

I agree that that claim is dubious. To keep the introduction simple, I'd just say "It is the heaviest known halogen", which is correct since Uus is currently not known to be a halogen. --Roentgenium111 (talk) 19:24, 24 September 2010 (UTC)

 Done--Roentgenium111 (talk) 19:16, 1 October 2010 (UTC)

Ridiculous

Ridiculous statement:

Since astatine is extremely radioactive, it should be handled with extreme care. Because of its extreme rarity, it is not likely that the general public will be exposed.

Is a shoot-yourself-in-the-foot-claim: a warning for the nearly impossible. Don't hang around when major asteroids annihilate your city! Or a herd of penguins. Rursus dixit. (^mbork³!) 19:46, 28 May 2011 (UTC)

Real picture?

Is the picture used in the front page real astantine? I can't imagine someone handling so radioactive compound without at least the foothold of lead shield. Or I am just mistaken here.. 188.230.132.58 (talk) 08:57, 26 June 2011 (UTC)

I think it is not. It is a non-free image from a web page that doesn't claim that the image presents astatine. I think it shouldn't be used, because the discouraged fair-use reason is used to present an image that is just an icon probably denoting radioactivity. Better a to use a Wikipedia-copyrighted icon that represents astatine then. Rursus dixit. (^mbork³!) 09:40, 18 July 2011 (UTC)

I agree with you. But what angers me is the image gives the wrong impression. Somebody would run into this site, thinking that Astatine can be made in visible amounts and even collected in an ampule like that, which is really a problem with todays folks and you probably know that. 'Normal' periodic table have radioactive sign, but I have seen tables on the internet use the mineral Autunite, which contain 'few atoms of Astatine at any given time'. 188.230.132.58 (talk) 12:04, 19 July 2011 (UTC)

The image has since been deleted. Lanthanum-138 (talk) 06:01, 14 August 2011 (UTC)

Commas and periods, and the quotation marks

Are commas and periods in- or outside the quotation marks? Originally tried to keep them in, but now see both variants. Sure I ain't no native English speaker to judge myself. But having looked over the Net, I noticed that all American cites I had seen, had told to put it in. Talked to another American about this before. He seems to have agreed (although it didn't affect his writing any after). So you tell me. Maybe it varies by state or whatever. I don't know for sure, but what I know is "keep it in no matter what." What would you say? Interested, R8R Gtrs (talk) 21:19, 3 March 2012 (UTC)

The standard on Wikipedia is to put them inside if the original quote had them, but outside otherwise - see MOS:LQ. Not having the sources of the quotes myself, I can't tell which to do unless for some reason I shorten a quote. Allens (talk | contribs) 21:33, 3 March 2012 (UTC)

Ooh. Wikipedia has own standards. Didn't know, though; thanks. Will have in mind any further.

Are there any real quotations? --R8R Gtrs (talk) 15:44, 4 March 2012 (UTC)

Quite welcome. Good question; I'll take a look... Allens (talk | contribs) 20:57, 7 March 2012 (UTC)

There are a few in the history section, depending on how you look at it; I've corrected one instance since I doubt that the original name of "anglo-helvetium" included a comma. I noted that, in references done by the wiki-pseudo-standard "cite book/journal" format, ending periods are after the quote marks (admittedly probably difficult to program it other ways, given that the separator is configurable as something other than a period), so I'm thinking they should probably go outside when it isn't a real quote, to keep things consistent. Allens (talk | contribs) 21:05, 7 March 2012 (UTC)

Isotopes table

I have not watched the article lately but my guess is that the table in the isotopes section is waaay to advanced for the purpose of a general article like this one. I suggest moving it into the isotopes article and leave behind a trimmed down version (without the mass excesses). Nergaal (talk) 04:03, 28 February 2012 (UTC)

Look. From my point of view, it is fine now. For an element we can talk hours about (any primordial one counts), there is no particular need to have a long Isotopes section. There's not that much to say about At, though, so I added a quite large discussion on the topic. and the table is for illustration. We could cut the isotope itself and daughter mass excesses, but we certainly have to keep the alpha energy decays. Again, from my point of view. You're a more experienced editor, you're more likely to be right. Agree with me? Or what? :)--R8R Gtrs (talk) 18:40, 2 March 2012 (UTC)

I would normally say to move the material into the isotopes article - except that:

• Its radioactive decay (and alpha decay at that) is one of the two main things of interest with astatine (the other being the chemical behavior of the heaviest halogen); and
• Only one isotope is of interest regarding the alpha decay.

Therefore, it seems appropriate to talk about isotopes more intensely than usual. (No pun intended regarding intensities of decay energy...) Regarding the mass excesses, I'd say that if those wind up being important in its alpha decay probabilities and energies, then keep them in the main article; otherwise, move as excessive (;-}) to the isotopes article. Allens (talk | contribs) 21:09, 2 March 2012 (UTC)

Mass excesses are needed to determine the decay energy. Here's in short how: You can weight the parent atom and the daughters (then sum masses of daughters). Given the masses of a proton and a neutron, you can figure what is the difference between masses of 85 unbound protons and 126 unbound neutrons. And calculate that of them all a in single bound system (<su p>211At nucleus). The difference (amu used for practical purposes, although some love SI kilogram perversions... I usually do too, but not with atoms) Then you can find the difference of masses or, equivalently (due to the same numbers of nucleons), mass excesses between ²¹¹At nucleus and its daughters, ²⁰⁷Bi and ⁴He nuclei. And according to the famous E=mc² (perfectly fine here) formula, calculate into energy, joules or electronvolts. Originally put them into the article just not to give the info, but also to give where it comes from, like the table explains where the alpha half-lives come from. (Figures need to be corrected significantly).

Personally, I'll be fine with either keeping or removing the mass excesses--R8R Gtrs (talk) 18:53, 3 March 2012 (UTC)

Ooh, one more: the masses excesses are easy to cite. without them, just with reaction energy released, we don't have a cite nor a common way to calculate it. So am now in favor of keeping it (hate it when rules lead over readability, but this is the life)--R8R Gtrs (talk) 19:47, 3 March 2012 (UTC)

Good point. Something in the back of my head was telling me they were important for the energies; dunno about the probabilities. Allens (talk | contribs) 22:13, 3 March 2012 (UTC)

Yes, they are useful, but this article is a review on the element. That is why there is a

Main article: Isotopes of astatine

link at the beginning of the section. Any additional information should me moved to the isotopes sub-article if this article is going to be put for FAC. Nergaal (talk) 21:33, 4 March 2012 (UTC)

Could you take a look around for something to cite that has the reaction energy released for each? Thanks! Allens (talk | contribs) 21:08, 7 March 2012 (UTC)

Naming of isotopes

I'm currently giving copyediting the page a try. Would it be preferable to use (for instance) ²¹¹Astatine (or ²¹¹At) or Astatine-211, for consistency? I'm not finding anything on this at, for instance, WikiProject Elements. The Isotopes of astatine page uses superscripts, while the FA Californium usually doesn't but sometimes puts that form in parentheses. Thanks! Allens (talk) 01:18, 18 February 2012 (UTC)

Hmmm, good question. I actually tend to name them like "astatine-211," but it's too problematic sometimes. Maybe we could switch to all symbols, ²¹¹At. I think, it's the best.--R8R Gtrs (talk) 16:49, 19 February 2012 (UTC)

OK, will do. Allens (talk) 18:22, 19 February 2012 (UTC)

Just re-read the article. Noticed that astatine isotopes are written as symbols, but other elements' are written in full. Is it OK? If you say yes, then yes. Maybe (and I'm becoming inclined to it) we could use symbols only in Isotopes section , as we do with chemical formulas in Chemistry section (solvents, etc. are written in full). What do you think? R8R Gtrs (talk) 21:08, 3 March 2012 (UTC)

Good question; should have seen that earlier myself. Hmm... I'm actually thinking ²⁰⁹Bismuth (as an example). That way, the reader doesn't need to know any chemical symbols other than for astatine, but it's more consistent with the astatine symbols. Your thoughts? Allens (talk | contribs) 21:42, 3 March 2012 (UTC)

Rather no; this isn't a way it is used in the literature and I even think this isn't correct; "bismuth-209," on the other hand, is pretty fine and has the same functions. Adding it, however, may make the thing too hard to read (but also may not). This was why I asked; if you see the way fine, I'll keep it the same.--R8R Gtrs (talk) 13:21, 14 March 2012 (UTC)

I wouldn't say "bismuth-209" or similar is hard to read; it's a pretty fair rendering of how they're (at least sometimes) talked about. I suggest keeping it the same for now, with a possibility for future revision (I'm thinking you or I might ask at WikiProject Elements and see if there's any sort of consensus among those who can decide for one or the other; my personal taste should not dictate things...). Allens (talk | contribs) 14:11, 14 March 2012 (UTC)

I just meant I tried to follow the same suit originally, but then I got simply tired of "bismuth-209," "astatine-211," etc. Maybe there is a way to word it better and look fine (and, well, this is what the copy-editing is for!)--R8R Gtrs (talk) 14:40, 14 March 2012 (UTC)

The Francium FA uses francium-### except for when showing nuclear reactions or chemical compounds. That is actually a bit easier on the eyes to read, I now suspect - no "jumping up and down" as your eyes scan across the screen. About the only other "linear" way I can think of is something like astatine/211, but I can't see any advantage of that over astatine-211 (can you?), and the element-### method is in use in other articles. About the only thing I would alter about astatine-211 is to make it instead astatine–211, with an endash used instead of a hyphen (it's admittedly hard to tell the difference...) because the MOS says to use an endash wherever you could just as well use a /. Allens (talk | contribs) 21:47, 14 March 2012 (UTC)

I can't :) But I don't even think "astatine–211" will do (en-dash), Wiki has a rule on that as well. Also, I basically thought that a hyphen connects prats of a word, while dashes connect different words....don't they?--R8R Gtrs (talk) 13:50, 21 March 2012 (UTC)

Huh! Naming conventions are for the titles of articles, mainly, but yes, I can see using them as a guide - good find! And that's very easy to convert (search & replace). The rule of thumb you mentioned is a pretty good one, but like everything it has its exceptions - for instance, the MOS says that if you're adding a hyphen/dash for a prefix, and what you're adding it to has a space in it, you use a endash: pre–credit cards (as in, the time prior to the invention of credit cards). Will do the fixing shortly. Allens (talk | contribs) 20:22, 21 March 2012 (UTC)

Trying to clarify

So:

1. it is allocated{{clarify|reason=Plates out on a cathode?}}-- maybe. Honestly, I'm not a native speaker and exactly here don't feel the difference (ashamed to admit). The enormous paper Soviet dictionary I have doesn't tell what the diff is.

• "Allocated" is typically understood as something that one would do with money or other resources - dividing the resource between items in a budget or whatever. I'm a bit confused as to why it'd be attracted to a cathode, though, considering that the previous sentence says it prefers being an anion (like other halogens). Allens (talk) 19:52, 19 February 2012 (UTC)

• . doi:10.1007/BF02037143. {{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help) might help.--Stone (talk) 21:27, 19 February 2012 (UTC)

• Are you suggesting sorption or adsorption as possible translations, instead of plating? Allens (talk) 22:38, 19 February 2012 (UTC)

OK, thanks, I'll remember. To your confusion: the previous sentences describe the element as a nonmetal; this one is a contarst (highlighted enough, I think, but do whatever is the best)

• Working on it... Allens (talk | contribs) 17:37, 26 February 2012 (UTC)

• OK, I've put in something. I concluded that (electro)plating should be primary, since it's there as a contrast to nonmetals, but that the possibility that sorption would be a better term should be noted along with Stone's reference (thanks!). Allens (talk | contribs) 19:22, 27 February 2012 (UTC)

1. however, experiments have shown that the actual astatine electronegativity is slightly below that of hydrogen{{clarify|reason=So what would the electronegativity be then? Or does the Pauling scale not go that far?}}-- Around 2.2 but slightly below, maybe 2.18 or about that, but I never saw the exact number, books (even well-written and respected among the scientists) don't give a value.
2. {{clarify|reason=Are the others not known, or simply not shown on the table?}}--simply not shown. No need in them all, just shows the extreme points: growth for alpha decay energy for At-211, the further growth for At-212 and -213, and decrease since then; also At-219, -220, and -221 to show alpha decay are not ~100% anymore.

• It may be preferable to note these as "example" isotopes instead of just "several" isotopes. Allens (talk) 19:52, 19 February 2012 (UTC)

1. {{clarify|reason=Why does the alpha decay probability jump around so much for lighter than astatine-210?}}-- Do you mean the exact jump for At-210--At-211 couple? If so, I dunno actually. Also seemed wicked for me (would normally expect the reverse). Will ask an expert (luckily, Wiki got some). If the whole At-210--At-213 row, then the peak for At-213 is easily explained: its daughter has 126 neutrons.

• I was actually referring to the 207-210 group. The reason for the size of the jump for the 210-211 ones would also be nice, yes. Regarding the peak for At-213, in other words, it's because alpha decay produces an isotope (of something or another) that has an unusually stable number of neutrons? Allens (talk) 19:52, 19 February 2012 (UTC)

Gimme time. I'll find out (i.e. will check the book, or whatever). For At-213, yes. Once I have more time, I'll write a more profound explanation (yet keeping understandable), if you want. Not gonna be a problem.

could you for now remove the At213's daughter's stability note? As a reader, I am there wondering why is At211 (N=126) less stable than At210. And as a writer, I can't (yet) explain itR8R Gtrs (talk) 18:53, 27 February 2012 (UTC)

OK, it's commented out. Allens (talk | contribs) 19:09, 27 February 2012 (UTC)

May be helpful--R8R Gtrs (talk) 12:20, 22 March 2012 (UTC)

1. The most stable of them is astatine-202m1,{{clarify|reason=The nuclear isomer article indicates that "m1" is not used, just "m", "m2", etc; a note may also be necessary to clarify exactly what astatine-202m1 means (first meta-state nuclear isomer of astatine-202)}}-- Half the truth, not always used, but sometimes is in scientific literature; the article itself names an isotope in that way. About explaining what "m1" means, you're probably right. I'll do it.

Have copyedited it - thanks! Allens (talk | contribs) 22:15, 3 March 2012 (UTC)

1. attributed Minder's results to contamination of his radon stream (radon-222 is the parent isotope of polonium-218).{{clarify|reason=In other words, contamination of his radon stream with another radon isotope?}}-- hmmm... New isotopes, in order to be identified, are often not studied chemically, but their decays are instead. The radon was probably not just radon-222, but also with traces of some beta decaying isotopes. He thought that the beta decays are astatine's fault. They were not.
2. Instead of searching for the element in nature, the scientists created it by bombarding bismuth{{clarify|reason=Which isotope of bismuth? 209?}}--yes. It's always Bi-209 (unless noted)
3. {{clarify|reason=The decay chains article appears to indicate that astatine wouldn't be part of the fourth decay chain anyway, not that it hasn't been found due to short life or something}} --well, yes. What can I do here?

• Just making sure this interpretation was correct before I clarified it in the text. Allens (talk) 19:52, 19 February 2012 (UTC)

1. The iodine acts as a carrier, ensuring that there is sufficient material for laboratory techniques such as filtration and precipitation to work.{{clarify|reason=Wouldn't reactions with iodine be a problem with this technique? If so, that should be remarked on}}-- Unlikely. Even the text says that iodine and astatine react only in vapor state; even using only simple logic, iodine won't work as a carrier for gaseous astatine (its boiling point is lower); otherwise, their reaction is not a problem.

• Actually, it also says they react in water, but provided it isn't in water, I suppose that would work. Allens (talk) 19:52, 19 February 2012 (UTC)

Well, I wasn't thinking of water. You need a carrier to handle the small pick of astatine easily (such as move in the space, keep, etc.). If you dissolve it in water...you can then just move the water.

(Always thought this is it, but this is only a part of story. Anyway the text says it needs a I₂/I^- solution. So if no iodides are present, the reaction won't go. If even they are formed somehow during the reaction... you can separate the ionic astatide and AtI chemically...it's not gonna be a problem)--R8R Gtrs (talk) 16:47, 12 March 2012 (UTC)

Makes sense. I'll try to fit this into the text (possibly in a note). Allens (talk | contribs) 17:08, 12 March 2012 (UTC)

1. camera{{clarify|reason=I'm reasonably certain this isn't the standard meaning of "camera"...}}-- Sure, it's not about the thing you take photos with :) "Camera" may be replaced with "cell" maybe, but this usage of the word also exists.

• "Cell" has enough meanings as "something closed from the environment" that it seems to work - thanks! Allens (talk | contribs) 22:17, 21 February 2012 (UTC)

1. to be fixedoxysalts{{clarify|reason=Example formulae would be nice here, since there's no "oxysalts" article}}-- I'll watch later for exact referenced examples. In general, this is a scientific jargon word which commonly refers to salts that contain (usually in the anion) oxygen, such as BaSO₄, CaCO₃, etc.

• I can stick in something like "oxysalts (oxygen-containing salts)" and expand it later with referenced examples. Allens (talk) 19:52, 19 February 2012 (UTC)

How about just "oxygen-containing salts ('oxysalts')"? Making the readers understand before giving such hard words is better than the reverse, and I'd prefer that to read.

• Normally, I would definitely agree... but in this case it's saying "silver(I), thallium(I) or caesium oxysalts", so that would be "silver(I), thallium(I) or caesium oxygen-containing salts ('oxysalts')", which at least to me is not clear on, among other things, what an oxysalt is (does it have something to do with silver/thallium/caesium?). Any thoughts?

Allens (talk | contribs) 22:17, 21 February 2012 (UTC)

Here are the examples: Tl₂Cr₂O₇, Ag₂Cr₂O₇, silver iodates, cesium heteropolytungstates (Cs_xH_3–xPW₁₂O₄₀), all hardly soluble. It'll maybe work as "with several silver(I), thallium(I) or caesium oxygen-containing salts, such as thallium(I) dichromate or silver(I) iodates, to form cationic astatine." Note to self: We can also say that the cation is hydrated in a solution (as, for example, H₂OAt₊).

• OK, done. Allens (talk | contribs) 21:54, 23 February 2012 (UTC)

1. a coordination selenocarbamide{{clarify|reason=A note with a definition would be nice here}}--Sure? No book I've seen does; should we? (besides, I don't yet know myself, but may lurk if you confirm)

• Well, otherwise the reader is left going "huh?"... for some reason, Google seems to think selenourea is one, BTW. No idea if it's correct or not, but searching for "selenocarbamide" gives a whole bunch of selenourea results... Allens (talk) 19:52, 19 February 2012 (UTC)

Google often picks unrelated but similar words if the one you typed in is rare. (Will figure the definite answer later; the original source has left me "huh?" as well, BTW)R8R Gtrs (talk) 18:53, 27 February 2012 (UTC)

Understand.... Allens (talk | contribs) 19:09, 27 February 2012 (UTC)

Looked up. The compound, also called "selenourea," is the selenium analog of urea ("carbamide"), with oxygen replaced with selenium.--R8R Gtrs (talk) 16:02, 4 March 2012 (UTC)

Should we replace selenocarbamine with selenourea, or just link it to selenourea? I'd say the former, provided there aren't any problems about referencing. (Sorry about the delay - I need to trim down my watchlist...) Allens (talk | contribs) 20:56, 7 March 2012 (UTC)

From my point, this would be no problem (if a text says, say, "Federal Republic of Germany," there's no problem to replace it with the term "Germany," which (in context) has the exactly same meaning. My guess is both replacing "selenocarbamine" with "selenourea" and adding a wikilink. You're not the one to apologize-- excuse me for this (I just couldn't edit Wiki, had no time...underslept).--R8R Gtrs (talk) 16:47, 12 March 2012 (UTC)

Understood fully! Done. Allens (talk | contribs) 17:08, 12 March 2012 (UTC)

1. bismuth oxide is pressed into{{clarify|reason=copper is not normally liquid}}--The original work (in Russian) uses the verb "впрессовывать," which Google Translate refers to as "pressed [sic] into." (I'd use the same verb) If you've got a very small ball of tungsten carbide (just an example of a very strong substance) and a wooden board, you can apply a strong force and the ball will stuck. This is what I mean. You can pick up any verb, I just can't think of one.

• Hmm... "forced into", perhaps? "forcibly fused with"? Allens (talk) 19:52, 19 February 2012 (UTC)

Any would probably do :)--R8R Gtrs (talk) 13:05, 21 February 2012 (UTC)

• OK, using "forcibly fused with". Allens (talk | contribs) 22:17, 21 February 2012 (UTC)

1. to be fixedcollected on a water-cooled surface,{{clarify|reason=Made of what material?}}--Similarly, will check later

Added the info into the text (it was platinum)--R8R Gtrs (talk) 18:32, 3 March 2012 (UTC)

Ah, it does turn out to be important (nobody'd want to use platinum otherwise!) - I suspected it was. Allens (talk | contribs) 21:45, 3 March 2012 (UTC)

Sorry, little time on hands. Hope I satisfied you (at least mostly), don't hesitate to keep asking--R8R Gtrs (talk) 19:23, 19 February 2012 (UTC)

• Very helpful, thanks! Understand on little time on hands - I am currently procrastinating before grading... Allens (talk) 19:52, 19 February 2012 (UTC)

1. is chemically a [[hydride]] rather than a [[halide]];{{Contradict-inline|article=Hydrogen astatide|date=February 2012|reason=That article appears to indicate this is a halide}}-- The chemical meaning of the "-ide" meaning is that it is the anion composed on one element in salts, and the more electronegative atom or polyatomic functional group composed on one element. Historically or traditionally, it was named "hydrogen astatide" and is still in literature similarly to other halogens. IUPAC nomenclature also recommends "hydrogen astatide" (or "astatidohydrogen," or "astatane," the second is the same as the first but is specific for the molecular form, and the last is just for HAt, not implying anything). The fact the hydrogen is the electronegative one was found out later. Even HUus may not be called hydride once synthesized (referred commonly just as H(117) now). Who knows?
2. bismuth is composed of only one isotope, bismuth-209,{{Contradict-inline|article=Bismuth#Isotopes|date=February 2012|reason=The article says there are multiple isotopes of bismuth}}--Well, yes, but for the real word there's only Bi-209. (There's no natural astatine from the same point of view, you'll never mine astatine) Do with this what you find the best.

• OK. I see; the other long-lived bismuth isotopes aren't on any naturally-occurring decay chains - the Isotopes of bismuth article is (slightly) clearer on this than the Bismuth article. Allens (talk | contribs) 22:17, 21 February 2012 (UTC)

(More to come)

If I missed something, please, add the other ones here as well. Will check the book soon, and complete the rest.--R8R Gtrs (talk) 13:05, 21 February 2012 (UTC)

Here are a few more:

1. The target is kept under a chemically neutral nitrogen atmosphere - I had earlier had a clarify on this, on the basis that astatine is said above to react with nitrogen, but I'm thinking this isn't going to be a concern since almost all astatine formed will not be on the surface (as well as that the conditions are probably not ones under which nitrogen and astatine react, given how stable nitrogen tends to be).

It never says that At₂ and N₂ react. There are just N-At bonds. (Also: Fluorine reaction with nitrogen is favorable (energy released), but that doesn't work for chlorine already. Even the N₂+F₂ reaction occurs only at electric discharge. On the other end, metals with similar electronegativity don't react with N₂. So don't think of N₂+At₂ reaction :) )

• Got it. Allens (talk | contribs) 21:54, 23 February 2012 (UTC)

1. AtBr requires, aside from astatine, an iodine/iodine monobromide/bromide solution.[why?]

Didn't check (yet), but more than sure the explanation will be too hard (contrast with the text). IMO, it's an example of something can be explained but it's better not to. Same probably applies to the vessel issue.--R8R Gtrs (talk) 13:26, 14 March 2012 (UTC)

No problem; just looking for things that might be asked during a FA review. Allens (talk | contribs) 13:49, 14 March 2012 (UTC)

I understand (and thanks for that!); although, I'll try to use the same hint there.--R8R Gtrs (talk) 14:46, 14 March 2012 (UTC)

1. No astatine fluoride has been discovered yet, and although its synthesis is thought to be possible, it may require a liquid halogen fluoride solvent;[why?] - normally, the problem is avoiding fluorine reacting with things, not getting it to react with them, from what I know of the subject...

You're right. (Things that come to my mind: fluorine isn't very interesting to try (you said why). Rutherfordium, for example, was tried with chlorine and bromine (corresponding Zr and Hf salts are not ionic, but volatile), not fluorine. This may be specific for fluorine, don't forget it reacts with almost anything. Maybe they tried the wrong conditions and fluorine reacted with anything else before getting to astatine. Or whatever)

1. which is put in a U-like quartz vessel.[why?] - why quartz? Why U-like - and, come to think of it, exactly what does that mean? A U-shaped cavity, or what?

The book doesn't say. The U-like is ... like communicating vessels? I mean, the shape. Why this shape? Maybe it's because in the communicating vessels, if you can fill it with mercury and then in one end add water, the level of liquid (the two don't dissolve in each other) won't the the same (have no idea why this helps, though). Why quartz? Maybe 'cause it doesn't change physical properties on quite high temperatures, doesn't even interact with astatine (unlike, say, gold) and is inert chemically (also quite cheap; not sure this one matters).

1. alpha particles are collided with bismuth. Even though there is only one bismuth isotope used, bismuth-209, the reaction may occur in three possible ways, producing 209At, 210At, and 211At. In order to eliminate the undesired nuclides, the maximum energy of the particle accelerator is set to 28 MeV - section, under synthesis, appears to be uncited.

Gave a ref and added a little more text (please have a look)--R8R Gtrs (talk) 19:37, 2 March 2012 (UTC)

• Looks good; did a slight copyedit. Allens (talk | contribs) 20:58, 2 March 2012 (UTC)

Thanks... Allens (talk | contribs) 22:17, 21 February 2012 (UTC)

Beta plus decay/positron emission

I don't find anywhere in the text, as opposed to the infobox, anything about that astatine seems to undergo specifically beta plus decay (positron emission) instead of beta minus decay (electron emission). Given that most people (like me) are going to first think of electron emission when they see "beta decay", I would think this needs clarifying. Do all isotopes of astatine that undergo beta decay emit positrons, or just the most stable ones? Allens (talk | contribs) 14:04, 24 March 2012 (UTC)

The chart of all nuclides: black ones are the stable (right ratios). (The X-axis is the neutron number, and the Y-axis is the proton number). The ones below the black (too little protons) are blue, beta minus (above are the pink, beta plus).

The explanation is very very basic, but this is what is enough to understand.

There is some neutron/proton ratio which is the best for an element. Neighboring elements all have such ratios similar. Compare ¹⁰B (1) and ¹¹B (1.2), ¹²C (1) and ¹³C (1.17), and ¹⁴N (1) and ¹⁵N (1.14). The nuclides with the ratio too low (too much protons), such as ¹¹C (0.83), ¹³N (0.86), etc. need to increase it to get stable: thus they decay into ¹¹B and ¹³C, emitting positrons. The nuclides with the ratio too high (too little protons) emit electrons (similarly).

Back to astatine. There are no stable isotopes, but there are (almost!) beta-stable (i.e., stable against beta, but not any other, decay) isotopes, which primarily alpha decay and β becomes unimportant. These are between ~213 and 215 (yellow means α decay). The lighter ones (too little protons), including the most stable At-209, -210, and -211, thus emit positrons. The ones heavier than these emit primarily electrons (although At-216 to -218 almost unnoticeable).

Now. Basically, I think it is a good idea to add "plus" in each place. Or replace it with "positron emission."--R8R Gtrs (talk) 14:54, 24 March 2012 (UTC)

Thanks! I've added a bit regarding that it's beta plus decay (positron emission) for lighter than astatine-216; I chose to explain a bit further because it's different for astatine-216 and heavier and because it's actually only mentioned once for astatine elements in general. (I'm still trying to decide whether the explanation should be in an (end)note; I currently lean toward no, so as to best explain the mention of beta plus decay later on. Your thoughts?) I gather that electron capture is another version of the same thing (a proton absorbing an electron in order to become a neutron), but happens when there's not enough energy difference to fuel the expulsion of a positron? Allens (talk | contribs) 23:00, 24 March 2012 (UTC)

You see that you need to spend energy to convert a proton into a neutron. But each nuclei has its own mass (and thus energy equivalent). If energy difference between the parent and the daughter is above 2m_ec² (m^e is the mass of an electron; c is the speed of light), there is enough energy to compensate and thus make favorable. If not, then the nucleus does not beta plus decay.

Ah. Of course (headslap) - the mass energy for the positron has to come from someplace, and neutrons are heavier than protons, so it can't come from converting between the two as it can for emitting an electron. Allens (talk | contribs) 16:46, 25 March 2012 (UTC)

Tried to remaster the wording (just to put in more info). Check, please--R8R Gtrs (talk) 11:49, 25 March 2012 (UTC)

Done; minor copyediting later (more for style than anything else), looks good! Allens (talk | contribs) 16:43, 25 March 2012 (UTC)

Diatomic astatine?

The general characteristics section notes that, 'Like other halogens, it is composed of diatomic At₂ molecules under standard conditions.[6]' Has the right reference to support this statement been given? In the reference in question, Zuckerman & Hagen 1989 (p. 21) note that, 'There is little evidence for the existence of diastatine (At₂).' They then say that, in respect of the claimed identification of At₂ in a radiogaschromotographic study, 'the identification must be considered questionable'.

The uncertain existence of diatomic astatine is also mentioned in the Gmelin handbook on At (1985, pp. 110, 116). Gmelin refers to two claims for the existence of diatomic At and then comments, 'As several authors have pointed out, the existence of molecular astatine is excluded by its extremely low concentrations under ordinary conditions of chemical experiments. Furthermore, the formation of At₂ does not seem to be realistic because any reaction which tends to split the At₂ molecule becomes thermodynamically favored at these low concentrations.'

There is also a discussion at Talk:Diatomic_molecule#Astatine which notes that according to the CRC Handbook of Chemistry and Physics, it is not yet known whether astatine forms diatomic astatine molecules. Sandbh (talk) 06:55, 24 March 2012 (UTC)

Thank you very much for the noting! I must've mistaken the exact reference when citing. Checked up your info. You seem to be right. Am removing statement it is At₂.--R8R Gtrs (talk) 13:06, 24 March 2012 (UTC)

Wouldn't this depend on concentration, which is not specified under the standard conditions discussed in the article linked to standard conditions? Allens (talk | contribs) 13:47, 24 March 2012 (UTC)

R8R, you're welcome. The sententence in question now reads as: 'Another notable difference from the other halogens is that astatine may not form diatomic molecules under standard conditions.[10]' I'm not sure this counts as a difference if the best that can be said is that such a difference *may* be so. It *may* turn out that such a difference does not exist. Nobody knows yet. That is the real difference worth noting: We know that the other halogens form diatomic molecules; we don't know for sure if At can and, if so, under what conditions. The sentence in question might be better expressed something like this:

Unlike its lighter congeners, the crystalline structure of astatine has not been determined (Donohue 1982, p. 400). Nor has it been established with any certainty as to whether astatine will form a diatomic molecule At₂ and, if so, under what conditions (Vasáros L & Berei K 1985 pp. 110, 166; Zuckerman & Hagen 1989, p. 21; Meyers 2002, p. 202)

References: Donohue J 1982, 'The structures of the elements,' Robert E. Krieger, Malabar, Florida, ISBN 0-89874-230-7; Vasáros L & Berei K 1985, 'General properties of astatine', in 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 — Preceding unsigned comment added by Sandbh (talk • contribs) 06:03, 25 March 2012 (UTC)

Well, the source I got states (not word-by-word, but keeping the sense), "All the halogens form diatomic molecules (except astatine)." It is also newer than most your sources (except for Meyers 2002, which my source is). I dunno... will say no diatomic molecules, simply as the most modern.--R8R Gtrs (talk) 11:17, 25 March 2012 (UTC)

No. It is not accurate to say that, 'Another notable difference from the other halogens is that astatine does not form diatomic molecules under standard conditions.' Nobody knows if At is or is not capable of forming a diatomic molecule. It may be able to; it may not be able to. The best that can be said is as follows: 'Another notable difference from the other halogens is that evidence for the existence of diatomic astatine is sparse and inconclusive (Vasáros L & Berei K 1985 pp. 110, 166; Zuckerman & Hagen 1989, p. 21; Meyers 2002, p. 202). Sandbh (talk) 10:18, 26 March 2012 (UTC)

Here's my point: I'm picking the newest ref up (most modern means most reliable, given same quality of true science books). The Google snippet says, "(except astatine)."It does not mean astatine may not form, it means, it does not form. And long as the source says no and not maybe, it is no and not maybe. (this is one of the basic rules of Wiki) If you've got the whole book dand it contradicts itself, then go ahead. Otherwise, I'd leave it as it is.R8R Gtrs (talk) 13:57, 26 March 2012 (UTC)

I think what is happening is that in the literature, extrapolations, theoretical predictions and claims, are being treated interchangeably. That it is, it is reasonably plausible to suggest the likely existence of diatomic astatine based on the the known existence of the ligher diatomic halogens. There are also lots of theoretical predictions as to the properties of diatomic astatine. And there are at least three papers claiming to have detected diatomic astatine, although there are more references disputing these claims. OTOH, you can pick up a beefy reference like Inorganic Chemistry, by Housecroft and Sharpe (2008, 3rd ed.) and they refer to diatomic astatine as if it was no big deal: 'Tracer studies (which are the only sources of information about the element) show that At₂ is less volatile than I₂' (p. 533). I'll see if I can post an edit that reflects this murky state of affairs. Sandbh (talk) 07:46, 29 March 2012 (UTC)

I've drafted an edit for the 2nd paragraph of the general characteristic section that keeps the same good structure but adds more content, plus older and later references, addressing the color and diatomicity questions. It's taking a while to get the wording clear and to check the details of the references, some of which are obscure (in French; in journals with similar but changed names mid-stream and no electronic access; hard to find conference proceedings). Will post soon, in between other obligations. Color and diatomicity remain open questions, with some good references going both ways in each case.Sandbh (talk) 13:46, 30 March 2012 (UTC)

Yes, many references seem to present extrapolations of the properties of astatine from bromine and iodine as if they were real measurements. Mendeleev would have called this predicting the properties of eka-iodine, and it should not be taken too seriously in 2012.

For the tracer method mentioned by Housecroft and Sharpe (p.469 in the 2nd edn 2005), I wonder how the original authors proved they had At₂ and not AtI, which would be the expected form of a trace of radioactive astatine in I₂. Anyway, if some papers claim to have detected At₂ and others contest the claim, then WP:NPOV requires that we cite both sides of the controversy.

On the other hand, the Separation section of the article claims that it is possible by a simple cold-finger method to enrich astatine content to 30%. If this is true, then the detection of At₂ is more credible. The reference given is a 1966 Russian analytical chemistry book by Lavrukhina and Pozdnyakov. Perhaps R8R Gtrs can find this Russian book and consider whether the 30% claim seems justified.

As I understand it from reading Gmelin (p. 195) the reference to a 30% yield is a reference to the "yield of the yield" i.e. 'Experiments with astatine are restricted to the tracer scale because of its short half-life and the low yield that can be achieved with the [required] nuclear reactions…The largest single batch produced seems to have been 50 nanograms. The highest concentration applied in experiments seems to be 10^–8 M, normally solutions <= 10^–10 M in astatine have been used.' Gmelin goes on to note that chemical experiments with larger amounts of At would be 'impossible' on account of radiation induced intense self-heating. As well as having to deal with high radioactivity, the solvent would boil away. In essence, 30 per cent of not much is not much at all. Sandbh (talk) 11:52, 31 March 2012 (UTC)

Yes, it is so. 30% of astatine produced can be separated. Not 30% of helium used turns into astatine.--R8R Gtrs (talk) 11:58, 2 April 2012 (UTC)

Also Sandbh mentioned French references above. If these references are accessible online, I can help with the French. Dirac66 (talk) 02:11, 31 March 2012 (UTC)

Appreciate the offer Dirac66. Not required on this occasion. Thanks all the same Sandbh (talk) 11:07, 31 March 2012 (UTC)

OK. I think you have done a good job of describing the state of knowledge about astatine and the reasons why we know so little. Dirac66 (talk) 18:53, 31 March 2012 (UTC)

Thank you. Building on good work by others. Sandbh (talk) 00:33, 1 April 2012 (UTC)

I've done some copyediting (more will be needed, such as on the reference formatting - not just in what you added; I spotted some other inconsistencies). Could someone please translate "Etude de la formation en phase gazeuse de composés interhalogénés d'astate par thermochromatographie"? I'd like to put a trans_title English translation with that reference. Thanks! Allens (talk | contribs) 20:39, 31 March 2012 (UTC)

Translation from French as requested: Study of the gas-phase formation of interhalogen compounds of astatine by thermochromatography. The word thermochromatography is defined here in Wiktionary.Dirac66 (talk) 23:11, 31 March 2012 (UTC)

Thanks! Allens (talk | contribs) 23:49, 31 March 2012 (UTC)

There are also a few other clarifications and translations (from German) needed for the references - I've marked these. Thanks! Allens (talk | contribs) 22:44, 31 March 2012 (UTC)

Beaut, thanks for your polished edits. Clarifications to follow soon. Sandbh (talk) 00:33, 1 April 2012 (UTC)

German translations added--R8R Gtrs (talk) 18:58, 1 April 2012 (UTC)

Thanks very much to all on the clarifications, translations, and compliment to my edits :-}! Allens (talk | contribs) 19:17, 1 April 2012 (UTC)

Bond energy value in gas

There is a value on a Webelements page of 80 kJ/mol for the At-At bond energy in gas-phase diatomic At₂. Not under standard conditions of course but still worth noting in the article if it is true at higher T or lower P. We should however have a source with reference to the original experiment (or calculation). Dirac66 (talk) 19:20, 26 March 2012 (UTC)

They cite CRC Handbook, 81st ed. I've got 84th :) They say it's for 298 K (25 deg C), rather than for gas phase. ~80 doesn't seem much. Analogous Li-Li in Li₂ value is ~110 (110.21±4), but lithium is certainly a metal. Can this be a partial conclusion of that it's not At₂ at STP (not for the article, just for myself)? [Comment by R8R Gtrs 27 March 2012]

Li is a metallic solid at 298 K but the vapor at high T has Li₂ molecules. For At at 298 K one cannot predict the most stable form just from the value of the bond energy. It would depend on all the energy and entropy terms involved in forming each possible form, so we need experimental data or at least a serious quantum-mechanical computation.

And thank you for noticing that Webelements cites the CRC Handbook. I have a much older 60th edition (1979-80!), but it's in there with the original reference: J.Drowart and R.E.Honig, J.Phys.Chem. 61, 980 (1957). So I looked up this paper and found that the authors did not actually do any measurement on astatine! Their table has diatomic molecules for 9 elements which they measured, 27 elements with previous literature values, and 5 elements (Al, At, Be, In, Tl) which they just estimated by interpolation (or extrapolation) vs. atomic number. So the value for At₂ cannot be taken very seriously, and in particular does not imply that diatomic At₂ has actually been observed. Now that I know it was just a rough estimate and not well justified, I conclude that this value should not be cited in Wikipedia. Dirac66 (talk) 20:34, 27 March 2012 (UTC)

All metals form polyatomic molecules when gases, don't they? (Hg is the odd one, but I very basically imagine why, and am sure you know why) It was just data for 298 K, not gas. Maybe they isolated two single atoms at the T, although there must be an easier way to get the info... Well, it's not the point. Sorry to know it's gonna be that complicated. But! If the calculations are needed, then the first one to do this would probably know what astatine at STP is, structurally. I googled heavily (and will again in some very near future), but found no such calculations. And I can believe none did the empiric crystal structure work. Determining melting and boiling point is actually easier to do. You only need to heat the thing and be careful-- to a not so high T (while separating, it's hotter: this is partially a factor for the separation to work). None photographed astatine either (even given that the modern science can photograph discrete molecules!)

Pfft.. they call themselves scientists :) Just kidding. They probably just needed to fill in an empty space. Sorry that it's just an estimate (although this could be guessed-- other values are given exact or within a small fixed range, not just "~80"). Then, we won't sure cite it. But I still don't think 80 sounds much anyway :)

And thanks for taking part...I find the great extent of your knowledge very useful, giving thus the owing credits. Were I ever that smart, I'd be quite proud of myself--R8R Gtrs (talk) 18:29, 28 March 2012 (UTC)

Apparently not all metals form polyatomic molecules when gases. Sugden (1930, p. 173) said that the alkali metals, silver, zinc, cadmium, (mercury) and thallium were monatomic, and also commented, on the basis of then scanty evidence, that the transition metals were monatomic. Dunstan (1968, p. 431) asserts that 'Vapours of true metals are monatomic.' No further explanation is provided as to what is meant by the expression 'true metal'. Timms and Turney (1977, p. 54) state that 'Most transition metals give monatomic vapors, but dimers and polymers form a small fraction of the vapors of many of the Main Group metals'. Wiberg 2001 (pp. 1097, 1294) says of the alkali metals that, 'The vapors contain primarily metals atoms but, in contrast to the alkaline earth vapors, they also contain some diatomic metals' and, later, that zinc and cadmium vapours are monatomic. Sandbh (talk) 12:18, 29 March 2012 (UTC)

• Dunstan S 1968, Principles of chemistry, D. Van Nostrand, London
• Sugden S 1930, The parachor and valency, George Routledge, London
• Timms PL & Turney TW 1977, 'Metal atom synthesis of organometallic compounds', in FGA Stone (ed.), Advances in organometallic chemistry, vol. 15, pp. 53–112
• Wiberg N 2001, Inorganic chemistry, Academic Press, San Diego

Then I guess an article needs to be fixed: Relativistic quantum chemistry. "In the gas phase mercury is alone in metals in that it is quite typically found in a monomeric form as Hg(g)."--R8R Gtrs (talk) 18:58, 1 April 2012 (UTC)

Strange. I was just reading Enthalpy of vaporization and it says, 'metals...often form covalently bonded molecules in the gas phase'. Odd (and annoying) that neither extract is supported by a citation. Sandbh (talk) 13:15, 2 April 2012 (UTC)

Solid state structure if not diatomic?

As for the solid at standard conditions, if it does not contain diatomic molecules, it would be interesting to know the true structure. Perhaps something simple like bcc or fcc? There was apparently enough sample to determine a melting point, so perhaps someone has done a crystallographic structure? Dirac66 (talk) 19:20, 26 March 2012 (UTC)

Vasáros & Berei, in Gmelin (1985) say that the thermodynamic properties of At species have only been estimated by various theoretical and and empirical calculations.

I've haven't been able to find any speculation in the literature as to the possible crystallographic structure of solid At. Extrapolating from the Goldhammer-Herzfeld metallicity values, per Edwards and Sienko (1983), for F, Cl, Br, and I gives a value for At of around 1.25, which is well into the metal range. This is also consistent with Siekierski and Burgess (2002, pp. 65, 122), who contend or presume that astatine would be a metal if it could form a condensed phase. However this is contradicted by Batsanov (1971, p. 811) who gives a calculated band gap energy for astatine of 0.7 eV, implying that it is semiconductor. Edwards & Sienko only went as far as saying that astatine is probably a semi-metal i.e. a metalloid. Throw possible relativistic effects into this mix, as with Hg and Po, and who knows.

As to obtaining enough of a sample of solid astatine to enable the determination of its crystallographic structure, Emsley (2001, p. 48) says that a visible piece of astatine would be immediately and completely vaporized because of the heat generated by its intense radioactivity. Greenwood & Earnshaw (2002, p. 885) say that 'weighable amounts of the element cannot be prepared and no bulk properties are known.' Kean (2011, p. 333) comments that 'No one will likely ever produce a visible sample of astatine…'.

It is interesting and frustrating question.

Given nano-tech I am surprised that the solid-state structure still seems to be an open question. Sandbh (talk) 09:37, 29 March 2012 (UTC)

• Batsanov SS 1971, 'Quantitative characteristics of bond metallicity in crystals', Journal of Structural Chemistry, vol. 12, no. 5, pp. 809–813
• Edwards PP & Sienko MJ 1983, 'On the occurrence of metallic character in the periodic table of the elements', Journal of Chemical Education, vol. 60, no. 9, pp. 691–696
• Emsley J 2001, Nature's building blocks: An A–Z guide to the elements, Oxford University, Oxford
• Greenwood NN & Earnshaw A 2002, Chemistry of the elements, 2nd ed., Butterworth-Heinemann, Oxford
• Kean S 2011, The Disappearing Spoon, Doubleday, London
• Siekierski S & Burgess J 2002, Concise chemistry of the elements, Horwood, Chichester
• Vasáros L & Berei K 1985, 'General properties of astatine', in Kugler HK & Keller C (eds) 1985, Gmelin handbook of inorganic and organometallic chemistry, 8th ed., 'At, Astatine', system no. 8a, Springer-Verlag, Berlin

I have had a brief look yesterday into the possible structural data and found none. It might be worth adding a brief summary of the findings by Sandbh into the article. Safety regulations strengthen roughly every decade, thus what could be done with radioactive solids in the 1970s will not be permitted now. Fundamental science is also in decline, thus there might be no progress in such matters. Materialscientist (talk) 10:04, 29 March 2012 (UTC)

Done. And not happy about the decline in fundamental science :( Sandbh (talk) 11:03, 31 March 2012 (UTC)

Characteristics section

I posted an edit to this section so as to improve its flow and internal consistency (see also the #22 'Rearrange sections?'). The story it tries to tell is: Context (radioactive; bulk unavailable; periodic table location) → Physical props. (estimations) → Chemical props. (tracer studies). I updated the information about HAt/AtH and the EN of At as per talk. I added a couple of citation needed tags, where I thought these were required. I left out the bit about At dissolving in water better than iodine since this factoid doesn't seem to add anything to the development of any of the paragraphs. I tried to keep the number of paragraghs low, out of respect for my predecessors. The rest of the article will need more work to pare back the information about HAt/AtH, and the EN of At. Sandbh (talk) 05:11, 8 April 2012 (UTC)

Picture - spectrum?

Are there any (ideally colored) spectrums available for astatine or one of its compounds (e.g., HAt)? If so, could that be used as a picture? Allens (talk | contribs) 14:05, 14 March 2012 (UTC)

Hmm. There must be some, but I have no idea how to get it. (Will try sometime later, but this is a nice addition rather than necessary, as few articles use it (not even all stable elements FAs!))--R8R Gtrs (talk) 15:10, 14 March 2012 (UTC)

Understand; I was thinking of this as a partial substitute for a picture of the element... Allens (talk | contribs) 15:59, 14 March 2012 (UTC)

There's probably no astatine spectrum. This site admits there was no info available (even though they got even for Es and a single Fr line)--R8R Gtrs (talk) 12:51, 8 April 2012 (UTC)

Heat of vaporization

The figure given in the element template box is 40 kJ•mol⁻¹, which seems out of place. Apparently it comes from Webelements, who give the following sources:

• G.W.C. Kaye and T.H. Laby in Tables of physical and chemical constants, Longman, London, UK, 15th edition, 1993.
• H. Ellis (Ed.) in Nuffield Advanced Science Book of Data, Longman, London, UK, 1972.
• A.M. James and M.P. Lord in Macmillan's Chemical and Physical Data, Macmillan, London, UK, 1992.
• D.R. Lide, (Ed.) in Chemical Rubber Company handbook of chemistry and physics, CRC Press, Boca Raton, Florida, USA, 79th edition, 1998.

Kaye & Laby (available online :) don't give a figure. Ellis (p. 59; available online :) gives a figure of 45.2. CRC 92^nd ed (2011) doesn't give a figure. Gmelin (1985, p. 117) cites three estimates, the lowest of these being 50 kJ/mol.

A simple atomic number extrapolation of the figures for the lighter halogens (F 6.51; Cl 20.41; Br 29.96; I 41.57) yields a figure for At of around 49.

I'll check hard copy James & Lord shortly (unless someone has them at hand). Curiously, Wolfram Alpha doesn't give a figure for At, despite listing James & Lord as a reference. Sandbh (talk) 08:37, 1 April 2012 (UTC)

ΔH(vap) is usually obtained from vapor pressure measurements using the Clausius-Clapeyron relation as ΔH(vap) = -R [d ln p/d(1/T)]. So I have plugged the six vapor pressure values in the infobox into the Excel file I use for this problem in intro phys chem, using the linear regression line for the slope, and found 85.4 kJ/mol! Assuming the vapor pressure values are for the solid, this value is actually ΔH(subl) = ΔH(fus) + ΔH(vap), but the result still implies a ΔH(vap) much higher than 40-50 kJ, since fusion always requires much less energy than vaporisation.

For comparison I did the same calculation on iodine. The infobox vapor pressures for iodine lead to ΔH(subl) = 58.7 kJ. The infobox on iodine gives ΔH(fus) = 15.52 kJ, ΔH(vap) = 41.57 kJ, sum = 57.09 kJ.

So here again the question is how was the data actually obtained - for ΔH(vap) AND for vapor pressure. Do we have actual measurements on pure (liquid or solid) astatine, or extrapolations for eka-iodine again? Dirac66 (talk) 15:47, 1 April 2012 (UTC)

Dirac66, yes your figure of 85.4 kJ/mol is spot on: Gmelin gives figures for ΔH(subl) of 86.91 (0 K) and 83.88 (298.15K). And ΔH(fus) = 23.85 @ 575K Sandbh (talk) 13:06, 2 April 2012 (UTC)

What does the scatter for the linear regression line look like? Any odd curvature, dual-line appearance, etc? I'm wondering if some of them are extrapolations and some aren't. Allens (talk | contribs) 17:49, 1 April 2012 (UTC)

No visible scatter at all. All 6 points are right on the line on my computer screen, and Excel gives the correlation coefficient as (-)0.99993. This suggests that the data are not measured vapor pressures, but values calculated from a linear equation. This would also be suggested by the values of p which are 1, 10, 100, 1000, 10000 and 100000 Pa - no one does an experiment like that.

I traced the data to Template:Infobox astatine to Chemical elements data references to Vapor pressures of the elements (data page), which refers to the CRC Handbook 2003 and in turn the AIP Handbook 1972. Perhaps this last source contains the original reference for astatine. If not we could check the source of the vapor pressures for other elements, since these sources gives vapor pressures of many elements at the same pressures. Dirac66 (talk) 20:21, 1 April 2012 (UTC)

The three Gmelin citations for At₂ (liquid -->gaseous) are 50.21 (given a b.p. of 543K); 54.39 (590K) and 90.37 (650K).

James & Lord (1992, pp. 449–450), the missing WEL reference, give the following figures: F₂ 6.54; Cl₂ 20.41; Br₂ 29.45; I₂ 41.8; At 30. Note the figure for At is given for a mole of At atoms, rather than a mole of At₂ molecules, as is the case with the other halogens.

The WP figures listed in the element template boxes are: F 6.51; Cl₂ 20.41; Br₂ 29.96; I₂ 41.57; At 40.

The American Institute of Physics (Gray 1972, p. 4–222 et seq.) does not give a figure for At, but lists these figures for the lighter halogens: F₂ 6.535; Cl₂ 20.41; Br₂: 29.45; I₂ 41.82

Ellis (2005) says: F 3.27; Cl 10.2; Br 15; I 20.85, and At 45.2, figures which appear to be for moles of atoms (see also below re the apparent source of the At figure).

The WEL figures are F 3.27; Cl 10.2; Br 14.8 I 20.9 and At 40 (the last figure seems out of place).

Stull & Sinke (1956, p. 48) give the following values, in old school units of cal/gfw:

F₂ 1,562; Cl₂ 4,878; Br₂ 7,170; I₂ 9,979; At₂ 21,600 (b.p. 650K)

Using the Ellis value for atomic Br gives 21,600/7170 x 30 = 90.3766 for diatomic astatine (= the high Gmelin value, and this is the same source cited by them) or 45.18 for the atom, which is nigh on the Ellis value (above) for At of 45.2.

In conclusion, I cannot find the WEL figure of 40 in any of the references cited by WEL. Nor can I find any values for the heat of vaporization of At in CRC or the AIP handbook.

Under these circumstances I'd be inclined to cite the middle of the Gmelin references, and list it as 'ca. 55', since the associated boiling point (590K) is closest to the commonly cited b.p. for At of 610K. Either that or show the value as 'At least 50', citing Gmelin. Grateful for any further perspectives on any of this. The comments to date have been remarkable!

• Gray DE 1972, American Institute of Physics handbook, 3rd ed., McGraw Hill
• Stull DR & Sinke GC 1956, Thermodynamic properties of the elements, Number 18 of the Advances in Chemistry Series, American Chemical Society

BTW, in terms of listing it as 'ca. 55', the {{circa}} template may be of use (c. 55 or c. 55). Allens (talk | contribs) 13:20, 2 April 2012 (UTC)

Can you determine which of all these values were obtained by actual measurements on samples of astatine? Given the difficulty of preparing astatine, I suspect at least some of the values may be just estimates, perhaps using the Clausius-Clapeyron relation with a normal boiling (or sublimation) point and an enthalpy of vaporization (or sublimation) extrapolated from other halogen values. Dirac66 (talk) 20:24, 2 April 2012 (UTC)

Hmm, no. As I understand it, all the figures are estimates.

The Ellis (2005) value comes from Stull & Sinke (1956), who say (p. 11): 'Astatine. These data are entirely estimated by comparison with the other halogens and are intended to serve only until measured data becomes available'.

Gmelin (1985, p. 113) says the thermodynamic properties of At species have only been estimated by various theoretical and empirical calculations. The low figure (50.21) was estimated 'using the empirical parameter Z’ '—no further explanation given. The high figure is that of Stull & Sinke (1956).

The James & Lord (1992) value comes from Cox JD, Wagman DD and Medvedev VA, CODATA key values for thermodynamics, Hemisphere Publishing Corp., New York, 1989. These values are available on line, with no explanation given as to how they were derived. Curiously, astatine is not listed. Sandbh (talk) 13:54, 3 April 2012 (UTC)

Sorry for turning boring now, but the article needs to benefit this discussion. My point is, we can give a range (stated the extreme values are approximations as well) rather then giving a single one (an endash will do). In theory, if we knew a vapor pressure at any given T, we could calculate (approximately) for any other (given the Clapeyron-Mendeleev equation). In practice, we know none, and the article may do without the table (well, unless we get any data). Opinions?--R8R Gtrs (talk) 16:40, 3 April 2012 (UTC)

Thinking about this some more I suggest listing just the middle Gmelin figure of 54.39, which is taken from Glushko VP, Medvedev VA & Bergma GA et al. 1966, Termicheskie Konstanty Veshchestv (Russian), Handbook of Thermal Constants?, part 1, Nauka, Moscow, p. 65. Knowing there is an approximate correlation between boiling point and heat of vaporization I did an x-y scatter plot of these well-known values for the lighter halogens (F₂, Cl₂, Br₂, I₂). To my surprise, a power trendline running through the four x-y coordinates shows a perfect (1.0) or near perfect (0.9998) correlation (can this be so?), depending on the precise value used e.g 14.8 or 15 for Br₂ heat of vaporization etc. The line itself is almost straight, in fact a straight trend line has a correlation of 0.9994. The values I get for At, with the power trendline, is b.p of 590K = 55.41 and for 610K = 57.49. Given this, I am inclined to cite the value of 54.39, since that is closest to the commonly quoted b.p. for At of 610K. Sandbh (talk) 13:17, 4 April 2012 (UTC)

Even simpler: Termal Constants of Substances. Also, what if there'll be anyone to try to cite another value? We could hide a note it's the most likely per talk or what? If so, that's fine and takes care of my anxiety.--R8R Gtrs (talk) 13:51, 7 April 2012 (UTC)

Melting/boiling point(s)

The "Estimation chemical form boiling point elementary astatine by radio gas chromatography" article gives an estimated boiling point of At₂ (if it exists) of 503 K, partially from experimental evidence (which is below the currently estimated melting point). Does the "Study of the gas-phase formation of interhalogen compounds of astatine by thermochromatography" (translated title) article give any info regarding melting/boiling points, as is implied by "thermochromatography"? Allens (talk | contribs) 15:09, 9 April 2012 (UTC)

I have mentioned the experimental evidence for a lower boiling point; I would much prefer citing a review article, however! Any idea where to find such? Allens (talk | contribs) 15:11, 9 April 2012 (UTC)

These values (575 mp 610 bp) seem to be ubiquitous. Gmelin cites CRC Handbook 62nd ed., 1981/82, p. B-7. They also give values of 575/608 in RA Honig, DA Kramer (RCA Rev. 30 (1969) 285/305; C. A. 71 (1969) No. 64413). Possibly these values were rounded up by CRC? 575/610 seem too 'five-ish' or perhaps it's just a coincidence. Sandbh (talk) 08:18, 10 April 2012 (UTC)

Rearrange sections?

Should the sections be rearranged to match Wikipedia:WikiProject_Elements/Guidelines? Allens (talk) 01:27, 18 February 2012 (UTC)

Leaning towards no. That layout is useful for elements like calcium or tin-- elements that occur in nature, can be well-studied and made industrially. Check out francium (very close in context to astatine, of similar stability and in the same nuclear region (between Bi and Th)) or ununoctium, both FAs. Isotopes and occurrence are more (relatively for the element) important, and are separate sections; uses and precautions are less important, and are kept together, also giving impression of biological roles, another unimportant (at all here) topic.--R8R Gtrs (talk) 16:58, 19 February 2012 (UTC)

I'll take a look at those two (francium and ununoctium) and compare to the current section arrangement; good thought! Allens (talk) 18:23, 19 February 2012 (UTC)

I have rearranged the sections to be closer to the arrangement in francium and ununoctium, while still preserving a logical sequence (e.g., talking about isotopes before talking about medical uses of one particular isotope). Allens (talk | contribs) 21:41, 21 February 2012 (UTC)

Good order now, except for that I'd move Chemical reactivity below History. The most related is Isotopes, so would best do before it. (Can't go later as it's followed by its own "relatives.") What do you think?R8R Gtrs (talk) 18:10, 27 February 2012 (UTC)

I can see that as one possibility; the other possibility is to make "Chemical reactivity" a subsection of "General characteristics" (calling the latter something like "Characteristics" or "Properties"). What do you think? ;-} Allens (talk | contribs) 18:22, 27 February 2012 (UTC)

Don't wanna move it to make a subsection. Too big a section results. By the same logic, we need to move Isotopes there (an even bigger section). There's some charm in that it's small and of similar size with the others. Let it be so :) R8R Gtrs (talk) 18:38, 27 February 2012 (UTC)

No problem... and it is so. Allens (talk | contribs) 18:49, 27 February 2012 (UTC)

R8R Gtrs, Allens: Please reconsider. Astatine has a good story to tell, one that is essentially no different to any of the other elements. The content that has been posted to date is remarkable. I cannot see any reason to not follow the standard layout and to let the article take its place, on an equal footing, alongside the other elements. There is enough quality content to do so:

0 Lead section

1 Properties

1.1 Physical

1.2 Chemical

2 Isotopes

3 Occurrence

4 Synthesis

4.1 Formation

4.2 Separation

5 Reactivity and compounds

6 History

7 Uses and precautions

etc

Sandbh (talk) 05:33, 8 April 2012 (UTC)

I do see your point, but I'd keep it as it is. Astatine has a specific topic called "Synthesis." After it, I would normally prefer to see what I can do with this (i.e., uses). Because typically, the astatine synthesized goes where it can be used (not studied). Plus, even uses are still dependent on isotopes, thus there can't be far away. And why is History so far from the beginning?--R8R Gtrs (talk) 15:27, 8 April 2012 (UTC)

in an elements article I would normally like to see 1. Properties (physical, chemical, isotopes) then 2. Occurence; 3. Production; 4. Compounds; 5. Uses; 6. Precautions; and then 7. History. Uses generally comes after Compounds rather than Production, since elements and their compounds tend to be treated interchangeably in this context. Precautions comes after Uses to again provide context. History comes towards the end since most people want to know about the chemistry first and then the 'dry' stuff, although I tend to look at the history as the reward. History usually comes earlier when there is not enough chemistry to talk about, which is clearly not the case in this instance, I am pleased to note. Sandbh (talk) 11:37, 9 April 2012 (UTC)

What about francium's order? And why have reactivity/compounds so far from the chemical properties (among which reactivity is one)? Allens (talk | contribs) 12:36, 9 April 2012 (UTC)

IMHO, it's kinda distorted (do I have to write constructive criticism?). The latter note makes sense to me, am switching--R8R Gtrs (talk) 12:53, 9 April 2012 (UTC)

Re why reactivity/compounds is so far away from the chemical properties of the element. This is discussed in the explanation of the element template. Early sections are about the element (properties, occurrence, production) then its compounds. The order of the francium article IMO doesn't flow very well either. Sandbh (talk) 10:13, 10 April 2012 (UTC)