ruthenium

[roo-thee-nee-uhm, -theen-yuhm]
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:
1840–50; < Neo-Latin, named after Ruthenia (from the fact that it was first found in ore from the region); see -ium

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To ruthenium
Collins
World English Dictionary
ruthenium (ruːˈθiːnɪəm)
 
n
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
 
[C19: from Medieval Latin Ruthenia Russia, where it was first discovered]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
American Heritage
Medical Dictionary

ruthenium ru·the·ni·um (rōō-thē'nē-əm)
n.
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.
Cite This Source
American Heritage
Science Dictionary
ruthenium   (r-thē'nē-əm)  Pronunciation Key 
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.
Cite This Source
Encyclopedia Britannica
Encyclopedia

ruthenium

(Ru), chemical element, one of the platinum metals of Group VIII of the periodic table, used as an alloying agent to harden platinum and palladium. Silver-gray ruthenium metal looks like platinum but is rarer, harder, and more brittle. The Russian chemist Karl Karlovich Klaus established (1844) the existence of this rare metal and retained the name his countryman Gottfried Wilhelm Osann had suggested (1828) for a platinum-group element whose discovery had remained inconclusive. Elemental ruthenium occurs in native alloys of iridium and osmium: up to 14.1 percent in iridosmine and 18.3 percent in siserskite. It also occurs in sulfide and other ores (e.g., in pentlandite of the Sudbury, Ont., Can., nickel-mining region) in very small quantities that are commercially recovered

Learn more about ruthenium with a free trial on Britannica.com.

Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
Cite This Source
Example sentences
All it takes is a catalyst of nickel or ruthenium, and the reaction occurs spontaneously.
But this compound includes ruthenium, a rare and expensive element.
Its high cost comes mainly from the platinum and ruthenium used as catalysts.
Related Words
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature