|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]|
ruthenium ru·the·ni·um (rōō-thē'nē-əm)
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.
|ruthenium (r-thē'nē-əm) Pronunciation Key
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.
(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
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