Talk:Thallium

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This is the talk page for discussing improvements to the Thallium article.

Article changed over to new Wikipedia:WikiProject Elements format by maveric149. Elementbox converted 12:16, 10 July 2005 by Femto (previous revision was that of 18:27, 2 July 2005).

Contents

[edit] Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory - Thallium. Additional text was taken directly from USGS Thallium Statistics and Information, from the Elements database 20001107 (via dict.org), Webster's Revised Unabridged Dictionary (1913) (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.

[edit] Talk

There was an Australian murderer that the press nicknamed "Aunt Thally" for her use of Thallium to kill her victims

What about the hallucinations? The James Randi Educational Foundation mentions [1] Scientist Sir Oliver Lodge (1851-1940) saw — in darkened rooms — glowing balls of fire that he believed were spirits. Co-incidentally, he also handled thallium, and in fact — erroneously — is credited with the discovery of that element. We now know that thallium is easily absorbed through the skin and produces hallucinations of colored balls of light for the victim....

[edit] Electrical properties

The article says that thallium sulfide's conductivity changes when it is exposed to infrared light. That indicates to me that it's a low-bandgap semiconductor. However, in the proper jargon, this would be a "III-VI" semiconductor. I've never heard of such a beast, though since thallium sits so low in the periodic table, it might have the right valency for that. Can anyone confirm or debunk this idea? More intriguing still is the mention of "thallium bromide-iodide crystals." I've never heard of any halogen compounds semiconducting, but that may just be a result of my ignorance. --Smack (talk) 04:40, 16 May 2005 (UTC)

III-VI semiconductors exists - GaSe is an example. I would not worry so much about the valency per se when considering semiconductor technology. The valence rules are simply a heuristic and do not reflect the complexity of bandgaps. Have you studied electrical engineering before? HappyCamper 12:14, 6 Jun 2005 (UTC)
Also, the reference to "thallium-bromide-iodide" crystals is correct. Think of it this way: It's a thallium iodide compound. This is a crystalline compound, where the network of atoms exists in all directions. Some of the iodine atoms have simply been replaced with bromine atoms. As a result, the crystal structure is distorted. The band structure would definitely be affected, although I don't think this semiconducts though - it's usually used as an agent to make really refined optical lenses. --HappyCamper 12:22, 6 Jun 2005 (UTC)

[edit] Reaction with water

The page currently states that the metal reacts with water to form thallium "hydride". This seems very unlikely to me. Perhaps it should say "hydroxide" instead?

See Wikipedia:Reference desk#Reaction of thallium with water. --Smack (talk) 05:31, 6 Jun 2005 (UTC)

[edit] Exposure to skin

In the Precautions section:

Contact with skin is dangerous and adequate ventilation should be provided when melting this metal. Exposure to soluble compounds of thallium shouldn't exceed 0.1 mg per m³ of skin in an 8-hour time-weighted average (40-hour work week).


Is it really supposed to read "per m³", and not "m²"? That's a whole lotta dermis.

-Misha Vargas

216.254.12.114 21:25, 18 November 2006 (UTC)

This should definitely be square meters, cubic meters don't make any sense, dimensionally. Chevalier de la charrette 13:34, 19 November 2006 (UTC)


I have just changed it to /square/ metres.

[edit] Thallium as a prescribed drug

I simply wish to pose a question regarding THALLIUM.

Does anyone have any information about the use of this element, as a prescribed drug in the treatment of emotionally disturbed (depressed or hyper-anxious) patients. I have come across anecdotal evidence of it's use by INDIAN military medics, specializing in psychiatry.

Any information glady appreciated.

Robert Marshall

This question will get more exposure if it is asked at the proper place at the reference desk --Dschwen 09:43, 20 November 2006 (UTC)

[edit] Claude-Auguste Lamy (1820-1878)

I have not been able to repair the redlink. Even the French Wikipedia site seems to have no article or information about this French scientist that discovered Thallium around the same time as Crookes. [2] gives some details:

Almost simultaneously Claude-Auguste Lamy (1820-1878) examined some slime from a sulfuric acid plant at Loos which was using Belgian pyrite and observed the green spectral line. He extracted thallium sesquichloride and isolated the metal new by electrolysis. Only after his discovery, he found out that Crookes had earlier discovered and named the new element, and gave Crookes the honour. Crookes presumed that his Thallium was something of the order of Sulphur, Selenium or Tellurium but Lamy found it to be a metal. In April 1862 he reported to the French Académie des sciences....

DFH 18:48, 20 November 2006 (UTC)

[edit] Radio-Thallium sources?

The article states that natural Thallium consists of two isotopes, both of which are stable. Given the current interest in the Alexander Litvinenko poisoning, and the suggestion that radioactive Thallium may have been used, it would be very interesting to have information on possible sources of radio-isotopes of Thallium. (For example, if it only comes from the nuclear fuel cycle, that would be interesting.) — Johan the Ghost seance 13:28, 21 November 2006 (UTC)

Thallium-201 is used in medical imaging, so I imagine hospitals order it from pharmaceutical/medical supply companies' catalogues! (eg MDS Nordian).--feline1 17:44, 21 November 2006 (UTC)
That's interesting, thanks; but if it's half-life is so short (see below), where do the pharmaceutical/medical supply companies get it from? — Johan the Ghost seance 22:10, 21 November 2006 (UTC)
I don't know the answer off the top of my head - but in principle, to find out, you need to know what radioactive decay series it is that produces the thallium-201... somewhere further up the chain, there'll be a parent nuclide with a pretty long half-life, which will either be mined out of the groud, or produced in a reactor. If the latter, it could be a useful by-product of something used for energy generation which they extract (eg from a nuclear power station), or it could be something which they deliberately synthesize by firing neutrons or other nuceli at something else (eg more likely from a physics lab facility somewhere). Whichever the case, you need to wait till the chain reaches thallium, then chemically extract the thallium and ship it off pretty sharpish to the hospital till it decays. One would imagine there are not many facilities in the world which produce this isotope, so it poses interesting opportunities re: 'tracing the murder weapon' in the current media story.--feline1 11:52, 22 November 2006 (UTC)
Yeah, that's pretty much what I was getting at -- I tried figuring out if it came from uranium fission by any obvious route, but my physics isn't up to that. Also, re. the medical supply side, I'm sure it's widely used as you say, but even so, wouldn't this use still be subject to some kind of nuclear regulation / oversight? Cheers! — Johan the Ghost seance 13:18, 22 November 2006 (UTC)

[edit] Half Life of Thallium-201?

What is the half life of Thallium-201? I see that this radioisotope has several mentions in Wikipedia e.g. on Radioisotopes but I have not been been able to locate its half-life. I would have expected to find it on this page as it seems like a popular/common isotope. - User:Murfas 17:35, 21 November 2006 (UTC)

It's about 3'n'half days, see http://www.webelements.com for instance. (i.e. a pretty short half life, just about long enough to get some made and it shipped to a hospital and used on a patient for myocardial imaging before the stuff all decays away to mercury).--feline1 17:44, 21 November 2006 (UTC)
See isotopes of thallium and its talk page for references. Femto 17:54, 21 November 2006 (UTC)


[edit] Broken Reference

The link for Reference 6 (gaijinpot) doesn't appear to work. Need to find or remove the reference. Motoma 02:17, 23 November 2006 (UTC)

Slashdot effect, apparently. I get a "high traffic, temporarily unavailable" message on that site. Let's wait. Femto 13:18, 23 November 2006 (UTC)

[edit] Alexander Litvinenko

I added the {{fact}} after the sentence recently added saying that Thallium was not used to poison Litvinenko. If this is true, then possibly he shouldn't even be mentioned here... Sewebster 06:24, 24 November 2006 (UTC)

The paragraph on Litvinenko has been removed and readded/rewritten a few times. If it is decided that it should stay, then perhaps an earlier version with references should be ressurected. Or at least a/some reference(s) should be added to the current blurb. Sewebster 20:01, 28 November 2006 (UTC)

[edit] Ref style

References are not in a uniform style (I bet there is a template for this). Looks like footnote style is winning out though. I will try to change them as I have time (unless someone objects). Sewebster 02:34, 25 November 2006 (UTC)

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