astatine


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as·ta·tine

 (ăs′tə-tēn′, -tĭn)
n. Symbol At
A highly unstable radioactive element, the heaviest of the halogen group, that resembles iodine in solution. Its longest lived isotope has a mass number of 210 and 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.

[Greek astatos, unstable; see astasia + -ine.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

astatine

(ˈæstəˌtiːn; -tɪn)
n
(Elements & Compounds) 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, 210At: 8.1 hours; probable valency: 1,3,5, or 7; melting pt: 302°C; boiling pt: 337°C (est)
[C20: from Greek astatos unstable (see astatic) + -ine2]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

as•ta•tine

(ˈæs təˌtin -tɪn)

n.
a rare element of the halogen family. Symbol: At; at. no.: 85.
[1945–50; < Greek ástat(os) unstable + -ine2]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.

as·ta·tine

(ăs′tə-tēn′)
Symbol At A highly unstable, radioactive element that is the heaviest of the halogen elements. The most stable of its many isotopes has a half-life of only about eight hours. Atomic number 85. See Periodic Table.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.astatine - a highly unstable radioactive element (the heaviest of the halogen series)astatine - a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium
chemical element, element - any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
halogen - any of five related nonmetallic elements (fluorine or chlorine or bromine or iodine or astatine) that are all monovalent and readily form negative ions
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
Translations
astat
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astaat
astatiini
astate
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asztácium
astat
アスタチン
astatium
astatinas
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astat
astato
astatin
astat
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астат
astatin
References in periodicals archive ?
The research partnership will see Telix explore the feasibility of using several of its clinical targeting agents in combination with astatine.
Such a geometrical criterion cannot be applied to the complexes with X = At because the van der Waals radius of astatine is unknown [50].
Earlier this year, physicists working at CERN, the European Organization for Nuclear Research, determined the ionization potential for astatine, a naturally occurring element so rare that, until now, its ionization potential couldn't be determined.
Two--francium (element 87) and astatine (85)--are so rare that Earth's entire crust is thought to contain no more than 30 grams, or about the weight of a paper clip, of each element at any one time.