Chemical elements
  Iridium
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
      Iridium Monochloride
      Iridium Dichloride
      Iridium Trichloride
      Potassium Chloriridite
      Sodium Chloriridite
      Ammonium Chloriridite
      Aquo Chloriridites
      Iridium Tetrachloride
      Potassium Chloriridate
      Sodium Chloriridate
      Ammonium Chloriridate
      Silver Chloriridate
      Thallium Chloriridate
      Iridium Tribromide
      Iridium Tetrabromide
      Potassium Bromiridate
      Sodium Bromiridate
      Ammonium Bromiridate
      Iridium Oxybromide
      Iridium Tri-iodide
      Potassium Iodiridite
      Iridium Tetra-iodide
      Potassium Iodiridate
      Iridium Monoxide
      Iridium Sesquioxide
      Iridium Dioxide
      Iridium Trioxide
      Iridium Monosulphide
      Iridium Sesquisulphide
      Iridium Disulphide
      Iridium Sesquisulphite
      Potassium Iridium Sulphite
      Iridium Sesquisulphate
      Potassium Iridium Alum
      Ammonium Iridium Alum
      Caesium Iridium Alum
      Rubidium Iridium Alum
      Iridium Disulphate
      Iridium Sesquiselenide
      Hydrogen Iridi-nitrite
      Potassium Iridi-nitrite
      Sodium Iridi-nitrite
      Ammonium Iridi-nitrite
      Hydrogen Iridicyanide
      Potassium Iridicyanide
      Barium Iridicyanide
    PDB 1c1k-4enb

Potassium Iridicyanide, K3Ir(CN)6






Pure iridium, when heated in a finely divided condition to a dull glow with potassium cyanide, yields a double cyanide.

The yield, however, is poor. A better method is to heat ammonium chloriridate with a slight excess of potassium cyanide for ten to fifteen minutes. Extraction of the melt with boiling water and subsequent evaporation yields crystals of the potassium iridicyanide, the other constituents, namely, potassium chloride and cyanide, being more soluble and remaining in solution.

Potassium iridicyanide yields hexagonal crystals (a: с = 1: 1.3319) which are colourless, transparent, and stable in air. The crystals dissolve in water easily, but only with difficulty in alcohol. The solution yields precipitates of various colours with salts of the heavy metals. With ferrous salts a white precipitate is obtained; with ferric, a bright yellow. Acetic acid is without action on potassium iridicyanide, although it decomposes the corresponding rhodicyanide. This affords, therefore, a useful method of separating rhodium from iridium.


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