Template talk:Infobox astatine

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Should the box have a 2.2 electronegativity for astatine, or could a <2.2 be fit in there, as per Barysz 2010?

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

Allens (talk | contribs) 17:53, 1 April 2012 (UTC)[reply]

Supported

Sandbh (talk) 13:27, 4 April 2012 (UTC)[reply]

The fully relativistic solid state has no band gap between the valence and conduction electrons: it is a metal even at ambient pressure. In fact, by analogy with high-pressure iodine, the researchers say astatine might even be a superconductor.

http://www.rsc.org/chemistryworld/2013/09/astatine-metallic-superconductor-predictions

It really probably that At is a (poor) metal even at pressure 1 atm or lower.

83.24.176.81 (talk) 19:09, 3 November 2013 (UTC)[reply]

Metallic At is becoming more and more plausible! Some of the last arguments left for metalloidal At are (1) narrow liquid range characteristic of nonmetals; (2) At predominantly forming anionic species in aqueous solution; and (3) forming astatides, astates and monovalent interhalogens analogous to the homologous iodine compounds. These are all chemical arguments: physically At is very metallic. For now I would still call it a metalloid, though the evidence is shifting markedly to the poor metal-side. Amusingly we have come full circle since its synthesis in 1940, when the investigators called it a relatively noble metal! Double sharp (talk) 02:37, 4 November 2013 (UTC)[reply]

I think that metal band structure is the argument over all others. Ge (semiconductor) and Sb (semimetal) haven't it. Metallic astatine will be something bizarre due to the position of astatine in the periodic table - it should be only a metalloid. If its liquid range is really so narrow (like for typical halogens?)? Is boiling lower than that of Hg? For me it is a metal, boot "the poorest of (recognised) poor metals". Gold has higher electronegativity in Pauling scale, forms auride ion but is not classified as metalloid or even poor metal. Gold, such as aluminium, due to its chemical properties, is on the "worse" side of metals. Platinum also has higher electronegativity than some nonmetals (H, P, Rn - in Pauling scale) and also can form simple anion (red, transparent caesium diplatinide). Chemistry of astatine may be more nonmetallic than chemistry of typical metalloids, but physical properties can be greatly metallic (even with boiling point about 600 K, less than bp of sulfur). Another oprtion is counting astatine to metalloids and poor metals (but for me naming is only as a metal looks better). It will also have not so bad cationic chemistry, unlike nonmetals (astatine looks as an element located between poor metals and metalloids (more than Sb and Ge), such as C, P, Se, (I) are intermediates between typical nonmetals and metalloids). I think that diastatine could ever not exist at ordinary conductions. Astatine is not a halogen, even if it is volatile and easily forms anion.

83.6.118.232 (talk) 18:33, 10 November 2013 (UTC)[reply]

It's because of the chemical/physical divide that I want to classify At as a metalloid. E117 would be a true poor metal, probably. We can discuss on WT:ELEM if you like, since it's affecting more than At and I really don't want multiple venues which would be kinda confusing. Double sharp (talk) 04:42, 11 November 2013 (UTC)[reply]

P.S. And yes, since a halogen means a nonmetal in group 17, I would argue that At is not a halogen. Double sharp (talk) 04:45, 11 November 2013 (UTC)[reply]

Curious. If At is a metal why would it no longer be a halogen? Sandbh (talk) 07:24, 8 April 2015 (UTC)[reply]

I thought we at enwiki concluded in 2013 that a halogen is a group 17 name, and metal-nonmetal is a property (trend even) in a period. Coming from different schemes then, they do not exclude/preclude one another. -DePiep (talk) 07:47, 8 April 2015 (UTC)[reply]

I dunno: it just doesn't really feel right to me to call a metal a halogen, come to think of it. Correct me if I'm wrong, but didn't the halogen article use to qualify the term, restricting it to nonmetals in group 17? I'm not sure if IUPAC says so, but it seems like "halogen" is more associated with metallicity than "pnictogen" or "chalcogen", because all the stable group 17 elements are in fact nonmetals.

IUPAC does cut off the halogens after At – although this is because they don't (yet) "believe" that E117 exists. However the element 117 article seems to base it on E117 likely having massively distinct properties from F, Cl, Br, I, and At: if this sort of usage is from a reliable source, then I'm not the only one who thinks the term "halogen" has a tinge of metal/nonmetal categorization to it, along with the neutral "group 17" meaning. Double sharp (talk) 12:26, 8 April 2015 (UTC)[reply]

Out of my depth. Though I'm interested how '"halogen" has a tinge of metal/nonmetal categorization to it' would work out. -DePiep (talk) 14:42, 8 April 2015 (UTC)[reply]