Sentence Examples


  • IRIDIUM (symbol Ir.; atomic weight 193.1), one of the metals of the platinum group, discovered in 1802 by Smithson Tennant during the examination of the residue left when platinum ores are dissolved in aqua regia; the element occurs in platinum ores in the form of alloys of platinum and iridium, and of osmium and iridium.
  • Iridium sesquioxide, Ir 2 0 3, is obtained when potassium iridium chloride is heated with sodium or potassium carbonates, in a stream of carbon dioxide.
  • The hydroxide, Ir(OH) 3, may be obtained by the addition of caustic potash to iridium sodium chloride, the mixture being then heated with alcohol.
  • The corresponding hydroxide, Ir(OH) 4, is formed when potassium iridate is boiled with ammonium chloride, or when the tetrachloride is boiled with caustic potash or sodium carbonate.
  • The sesquisulphide, Ir 2 S 3, is obtained as a brown precipitate when sulphuretted hydrogen is passed into a solution of one of the sesqui-salts.

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