meitnerium(redirected from unnilennium)
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Related to unnilennium: Element 109
n. Symbol Mt
An artificially produced radioactive element with atomic number 109 that has known isotopes with mass numbers ranging from 265 to 279. The isotope with the longest confirmed half-life (0.7 seconds) is Mt-268. See Periodic Table.
[After Lise Meitner.]
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 synthetic element produced in small quantities by high-energy ion bombardment. Symbol: Mt; atomic no: 109
[C20: named after Lise Meitner]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
Symbol Mt A synthetic, radioactive element that is produced by bombarding bismuth with iron ions. Its most stable isotope has a half-life of 70 milliseconds. Atomic number 109. 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.||meitnerium - a radioactive transuranic element|
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