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[law-ren-see-uh m] /lɔˈrɛn si əm/
noun, Chemistry
a synthetic, radioactive, metallic element. Symbol: Lr; atomic number: 103.
1960-65; Lawrence Radiation Laboratory, Berkeley, California + -ium Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for lawrencium


/lɒˈrɛnsɪəm; lɔː-/
a transuranic element artificially produced from californium. Symbol: Lr; atomic no: 103; half-life of most stable isotope, 256Lr: 35 seconds; valency: 3
Word Origin
C20: named after Ernest Orlando Lawrence (1901–58), US physicist
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for lawrencium



1961, Modern Latin, from the name of Ernest O. Lawrence (1901-1958), U.S. physicist, cyclotron pioneer and founder of the lab where it was discovered.

Online Etymology Dictionary, © 2010 Douglas Harper
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lawrencium in Medicine

lawrencium law·ren·ci·um (lô-rěn'sē-əm, lō-)
Symbol Lr
A radioactive synthetic element produced from californium and having isotopes with mass numbers 253 through 260 and half-lives of 650 milliseconds to 3 minutes; atomic number 103.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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lawrencium in Science
Symbol Lr
A synthetic, radioactive metallic element of the actinide series that is produced by bombarding californium with boron ions. Its most stable isotope is Lr 262 with a half-life of 3.6 hours. Atomic number 103. See Periodic Table.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Article for lawrencium


(Lr), synthetic chemical element, the 14th member of the actinoid series of the periodic table, atomic number 103. Not occurring in nature, lawrencium (as the isotopes lawrencium-257, lawrencium-258, and lawrencium-259) was produced (1961) by Albert Ghiorso, T. Sikkeland, A.E. Larsh, and R.M. Latimer at the University of California, Berkeley, by bombarding a mixture of the longest-lived isotopes of californium (atomic number 98) with boron ions (atomic number 5) accelerated in a heavy-ion linear accelerator. A team of Soviet scientists at the Joint Institute for Nuclear Research in Dubna discovered (1965) lawrencium-256 (35-second half-life), which the Berkeley group used to show that lawrencium behaves more like the tripositive elements in the actinide series than like predominantly dipositive nobelium (atomic number 102).

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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