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Astatine-218 was the first astatine isotope discovered in nature. [113] Astatine-219, with a half-life of 56 seconds, is the longest lived of the naturally occurring isotopes. [6] Isotopes of astatine are sometimes not listed as naturally occurring because of misconceptions [103] that there are no such isotopes, [114] or discrepancies in the ...
Astatine (At) 85 ἄστατος (astatos) Greek "unstable" From Greek ἄστατος (astatos), meaning "unstable". · Former name alabamine (Ab) was an earlier proposed name for astatine Radon (Rn) 86 radium: Latin via German and English [57] Contraction of radium emanation, since the element appears in the radioactive decay of radium.
Structure of astatine monoiodide, one of the astatine interhalogens and the heaviest known diatomic interhalogen. Astatine is known to react with its lighter homologs iodine, bromine, and chlorine in the vapor state; these reactions produce diatomic interhalogen compounds with formulas AtI, AtBr, and AtCl. [4]
In 1950 astatine was described as a halogen and (therefore) a reactive nonmetal. [467] In 2013, on the basis of relativistic modelling, astatine was predicted to be a monatomic metal, with a face-centred cubic crystalline structure. [468] Several authors have commented on the metallic nature of some of the properties of astatine.
Platinum is a chemical element; it has symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish platina, a diminutive of plata "silver". [7] [8] Platinum is a member of the platinum group of elements and group 10 of the periodic table of ...
Pages in category "Astatine" The following 3 pages are in this category, out of 3 total. This list may not reflect recent changes. ...
[7] [8] He also claimed to have found element 85, now called astatine, in monazite sand, a mineral which is rich in rare earth elements and thorium. [9] He named the two elements after the American states Virginia and Alabama, virginium and alabamine. Wendell Mitchell Latimer claimed to have discovered tritium in 1933 using the same method. [10]
All of astatine's isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours. Astatine is sometimes described as probably being a black solid (assuming it follows this trend), or as having a metallic appearance. Astatine is predicted to be a semiconductor, with a band gap of about 0.7 eV.