radon(redirected from 222Rn)
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n. Symbol Rn
A colorless, radioactive, inert gaseous element that is formed by the radioactive decay of radium and is used to produce neutrons for research. Its most stable isotope is Rn-222 with a half-life of 3.82 days. A natural source of radiation found in most soils and groundwater, radon poses a serious health threat if inhaled. Atomic number 86; melting point -71°C; boiling point -61.7°C; density of gas 9.73 grams per liter; specific gravity (solid) 4. See Periodic Table.
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.
(Elements & Compounds) a colourless radioactive element of the rare gas group, the most stable isotope of which, radon-222, is a decay product of radium. It is used as an alpha particle source in radiotherapy. Symbol: Rn; atomic no: 86; half-life of 222Rn: 3.82 days; valency: 0; density: 9.73 kg/m3; melting pt: –71°C; boiling pt: –61.7°C
[C20: from radium + -on]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
a chemically inert, radioactive gaseous element produced by the decay of radium: emissions produced by outgassing of rock, brick, etc., are a health hazard. Symbol: Rn; at. no.: 86; at. wt.: 222.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
Symbol Rn A colorless, odorless, radioactive element that is a noble gas. It is produced by the radioactive decay of radium and occurs in minute amounts in soil, rocks, and the air near the ground. Radon is used as a source of radiation for the treatment of cancer and other diseases. Its most stable isotope has a half-life of about four days. Atomic number 86. 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.
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|Noun||1.||radon - a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health|
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
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
radon[ˈreɪdɒn] N (also radon gas) → radón m
Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005
radon[ˈreɪdɒn] n → radon m
Collins English/French Electronic Resource. © HarperCollins Publishers 2005
n (Chem) → Radon nt
Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007
n. radón, elemento radiactivo gaseoso.
English-Spanish Medical Dictionary © Farlex 2012
radonn radón m
English-Spanish/Spanish-English Medical Dictionary Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.