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promethium

[pruh-mee-thee-uh m] /prəˈmi θi əm/
noun, Chemistry
1.
a rare-earth, metallic, trivalent element. Symbol: Pm; atomic number: 61.
Origin of promethium
1945-1950
1945-50; < New Latin; see Prometheus, -ium
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Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for promethium

promethium

/prəˈmiːθɪəm/
noun
1.
a radioactive element of the lanthanide series artificially produced by the fission of uranium. Symbol: Pm; atomic no: 61; half-life of most stable isotope, 145Pm: 17.7 years; valency: 3; melting pt: 1042°C; boiling pt: 2460°C (approx.)
Word Origin
C20: New Latin from Prometheus
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
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Word Origin and History for promethium
n.

radioactive element, long one of the "missing elements," 1948, so called by discoverers Jacob Marinsky and Lawrence Glendenin, who detected it in 1945 in the fusion products of uranium while working on the Manhattan Project. From Prometheus, who stole fire from the gods and was punished for it, + element name ending -ium. "The name not only symbolizes the dramatic way in which the element may be produced in quantity as a result of man's harnessing of the energy of nuclear fission, but also warns man of the impending danger of punishment by the vulture of war." [Marinsky and Glendenin]

Online Etymology Dictionary, © 2010 Douglas Harper
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promethium in Medicine

promethium pro·me·thi·um (prə-mē'thē-əm)
n.
Symbol Pm
A radioactive rare-earth element prepared by fission of uranium. Pm 145 is the longest-lived isotope with a half-life of 17.7 years. Atomic number 61; melting point 1,042°C; boiling point 3,000°C; valence 3.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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promethium in Science
promethium
  (prə-mē'thē-əm)   
Symbol Pm
A radioactive metallic element of the lanthanide series. Promethium does not occur in nature but is prepared through the fission of uranium. It has 17 isotopes, one of which is used to make long-lived miniature batteries that work at extreme temperatures for up to five years. The longest-lived isotope, Pm 147, has a half-life of 2.5 years and is used as a source of beta rays. Atomic number 61; melting point 1,168°C; boiling point 2,460°C; valence 3. See Periodic Table.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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