astatinen.
/ˈastətiːn/, /ˈastətɪn/, U.S. /ˈæstətin/ Chemistry.
A radioactive element of short half-life, which is rare in nature but can be made artificially; the heaviest element of the halogen group. (Formerly called alabamine n. and anglo-helvetium n.) Symbol At, atomic number 85, principal isotope 211.
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alabamine1932
helvetium1940
anglo-helvetium1942
astatine1947
At1947
1947 D. R. Corson et al. in Nature 4 Jan. 24/1 We propose to call element 85 ‘astatine’ from the Greek ἄστατος, unstable. Astatine is in fact the only halogen without stable isotopes. The corresponding chemical symbol proposed is ‘At’.
1950 F. Gaynor Conc. Encycl. Atomic Physics 21 Astatine, a very rare radioactive element..first announced by Allison and Murphy under the name alabamine in 1929; also referred to formerly as eka iodine.
1950 F. Gaynor Conc. Encycl. Atomic Physics 21 The name astatine was officially adopted by International Union of Chemistry and announced by the American Chemical Society on September 23, 1949.
1950 N. V. Sidgwick Chem. Elements II. 1260 Elem. No. 85 (Astatine). There seems to be no doubt now that this element has been obtained as artificial product of nuclear bombardment.
This entry has not yet been fully updated (first published 1972; most recently modified version published online December 2021).
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n.1947