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[roo-thee-nee-uh m, -theen-yuh m] /ruˈθi ni əm, -ˈθin yəm/
noun, Chemistry.
a steel-gray, rare metallic element, belonging to the platinum group of metals. Symbol: Ru; atomic weight: 101.07; atomic number: 44; specific gravity: 12.2 at 20°C.
Origin of ruthenium
1840-50; < New Latin, named after Ruthenia (from the fact that it was first found in ore from the region); see -ium Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for ruthenium
Historical Examples
  • In Fremys process for separating osmium from the residues of platinum ore, ruthenium occurs in a dioxide.

  • The lower ovoids in ruthenium are identical in composition, with those of iron, cobalt and nickel and may be studied under Iron.

    Occult Chemistry Annie Besant and Charles W. Leadbeater
British Dictionary definitions for ruthenium


a hard brittle white element of the platinum metal group. It occurs free with other platinum metals in pentlandite and other ores and is used to harden platinum and palladium. Symbol: Ru; atomic no: 44; atomic wt: 101.07; valency: 0–8; relative density: 12.41; melting pt: 2334°C; boiling pt: 4150°C
Word Origin
C19: from Medieval Latin Ruthenia Russia, where it was first discovered
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 ruthenium

metallic element, 1845, named by Russian chemist Karl Klauss, from a name proposed earlier (1828) in reference to a metal extracted from ores from the Ural Mountains of Russia (see Ruthenian).

Online Etymology Dictionary, © 2010 Douglas Harper
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ruthenium in Medicine

ruthenium ru·the·ni·um (rōō-thē'nē-əm)
Symbol Ru
A hard acid-resistant metallic element that is found in platinum ores. Atomic number 44; atomic weight 101.07; melting point 2,334°C; boiling point 4,150°C; specific gravity 12.41; valence 0, 1, 2, 3, 4, 5, 6, 7, 8.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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ruthenium in Science
Symbol Ru
A rare, silvery-gray metallic element that is hard, brittle, and very resistant to corrosion. It is used to harden alloys of platinum and palladium for jewelry and electrical contacts. Atomic number 44; atomic weight 101.07; melting point 2,310°C; boiling point 3,900°C; specific gravity 12.41; valence 0, 1, 2, 3, 4, 5, 6, 7, 8. See Periodic Table.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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