a rare element of the halogen family. Symbol: At; atomic number: 85.
Origin of astatine
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a radioactive element of the halogen series: a decay product of uranium and thorium that occurs naturally in minute amounts and is artificially produced by bombarding bismuth with alpha particles. Symbol: At; atomic no: 85; half-life of most stable isotope, 210 At: 8.1 hours; probable valency: 1,3,5, or 7; melting pt: 302°C; boiling pt: 337°C (est)
Word Origin for astatine
C20: from Greek astatos unstable (see astatic) + -ine ²
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Online Etymology Dictionary, © 2010 Douglas Harper
n. Symbol At
A radioactive halogen element. Its longest lived isotope has a mass number of 210 and a half-life of 8.1 hours. Atomic number 85.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
A highly unstable, rare, radioactive element that is the heaviest of the halogen elements. Its most stable isotope has a half-life of 8.3 hours. Atomic number 85; melting point 302°C; boiling point 337°C; valence probably 1, 3, 5, 7. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.