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unnilhexium

[yoo-nil-hek-see-uh m]
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noun Chemistry, Physics.
  1. former name of seaborgium. Symbol: Unh
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Origin of unnilhexium

1975–80; < Latin ūn(us) one + nīl nothing + Greek héx six + New Latin -ium -ium
Also called element 106.

seaborgium

[see-bawr-gee-uh m, see-bawr-]
noun Chemistry, Physics.
  1. a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Sg; atomic number: 106.
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Origin of seaborgium

named after U.S. chemist Glenn T. Seaborg; see -ium
Formerly unnilhexium, element 106.

element 106

noun Chemistry, Physics.
  1. seaborgium.
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Origin of element 106

First recorded in 1975–80
Formerly unnilhexium.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for unnilhexium

seaborgium

noun
  1. a synthetic transuranic element, synthesized and identified in 1974. Symbol: Sg; atomic no: 106
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Word Origin

C20: named after Glenn Seaborg
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

unnilhexium in Science

seaborgium

[sē-bôrgē-əm]
Sg
  1. A synthetic, radioactive element that is produced by bombarding californium with oxygen ions or bombarding lead with chromium ions. Its most long-lived isotopes have mass numbers 259, 261, 263, 265, and 266 with half-lives of 0.9, 0.23, 0.8, 16, and 20 seconds, respectively. Atomic number 106. See Periodic Table.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.