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Occurring as single atoms: Helium is a monatomic gas.

mon′a·tom′ic·al·ly adv.
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.


(ˌmɒnəˈtɒmɪk) or


1. (Chemistry) (of an element) having or consisting of single atoms: argon is a monatomic gas.
2. (Chemistry) (of a compound or molecule) having only one atom or group that can be replaced in a chemical reaction
3. (Chemistry) a less common word for monovalent
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˌmɒn əˈtɒm ɪk)

1. having one atom in the molecule.
2. containing one replaceable atom or group.
3. having a valence of one.
mon`a•tom′i•cal•ly, adv.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Adj.1.monatomic - of or relating to an element consisting of a single atommonatomic - of or relating to an element consisting of a single atom; "helium and argon are monatomic gases"
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
The viscosity of a pure monatomic gas of molecular weight Mi using the Lennard-Jones parameters I and a|.
Gordon Elliott, trainer of Mill Quest, Measureofmydreams, Barra, Swingbridge, Ned Stark, Cecil Corbett, Monatomic and Timiyan The trip is a bit of a worry for Mill Quest but Katie O'Farrell is takes 5lb off.
He probably has most to fear from the former course winner Monatomic who would have won here earlier in the season only to fall late on.
Progressive Monatomic (4.15) looks the best of Gordon Elliott's team in the feature chase.
where [gamma] is the ratio of specific heats of argon, [gamma] [approximately equal to] 1.667 for a monatomic gas, and v is the average particle velocity given by
MONATOMIC will be strongly-fancied to continue the good form of Gordon Elliott, Gigginstown House Stud and Davy Russell (right) in today's Clonmel Supporters Club Beginners Chase.
Russell doubled up in the second race on the card when he partnered Monatomic - in the same Gigginstown House Stud colours he wore at Aintree on Tiger Roll - in the Waterford & Tramore Racecourse Family Fun Afternoon Maiden Hurdle.
After numerous impacts between the gaseous molecules and walls, the above pumping results in the total kinetic energy [mathematical expression not reproducible] of an N-molecule monatomic gas being defined by [1]:
Note that the present theory is valid for any crystal structure including complex systems; therefore, the other developments for the monatomic [27] and bcc [28] crystals are only its special cases.
Argon atom is usually used in molecular dynamic simulation for it's a monatomic molecule.
The concentration of dissolved diffusing hydrogen (in monatomic state) is sufficiently low and the diffusion flux can be considered proportional to the concentration gradient.
Macdonald, "A unified approach to modelling the charge state of monatomic hydrogen and other defects in crystalline silicon," Journal of Applied Physics, vol.