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?
Metallic at ambient pressure?
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.
It really probably that At is a (poor) metal even at pressure 1 atm or lower.
- 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)
Rather a metal, not a metalloid
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.
- 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)