Adjacent Words

astatine definitions

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WordNet (r) 3.0 (2005)

n
1: a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium [syn: astatine, At, atomic number 85]

Merriam Webster's

noun Etymology: Greek astatos unsteady, from a- + statos standing, from histanai to cause to stand — more at stand Date: 1947 a radioactive halogen element discovered by bombarding bismuth with alpha particles and also formed by radioactive decay — see element table

Dictionary of the Elements

astatine
Symbol: At
Atomic number: 85
Atomic weight: (210)
Radioactive halogen element. Occurs naturally from uranium and thorium decay. At least 20 known isotopes. At-210, the most stable, has a half-life of 8.3 hours. Synthesized by nuclear bombardment in 1940 by D.R. Corson, K.R. MacKenzie and E. Segre at the University of California.

Oxford Reference Dictionary

n. Chem. a radioactive element, the heaviest of the halogens, which occurs naturally and can be artificially made by nuclear bombardment of bismuth. Usage: Symb: At. Etymology: formed as ASTATIC + -INE(4)