Chemical elements
  Tin
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
      Tetramethyl Stannane
      Methyl stannic chloride
      Tin Tetra-ethyl
      Tin Tri-ethyl
      Stannous Fluoride
      Stannic Fluoride
      Sodium Stannifluoride
      Potassium Stannifluoride
      Ammonium Stannifluoride
      Stannous Chloride
      Stannic Chloride
      Chlorostannates
      Stannous Bromide
      Stannic Bromide
      Stannous Iodide
      Stannic Iodide
      Mixed Stannic Halides
      Stannous Oxide
      Stannous Hydroxide
      Stannic Oxide
      Potassium Stannate
      Stannic Acid and its Derivatives
      Parastannic Acid
      Stannyl Chloride
      Parastannyl Chloride
      Stannous Sulphide
      Stannic Sulphide
      Stannic Oxysulphide
      Stannic Iodosulphide
      Stannous Sulphate
      Stannic Sulphate
      Stannic Nitrate
      Stannous Nitrate
      Phosphor-tin
      Stannioxalic Acid
      Stannous Tartrate
      Tin and Silicon
      Stannous Tungstate
    PDB 3e94-3kwy

Stannic Iodide, SnI4






Stannic Iodide, SnI4, is formed from its elements, and is conveniently prepared by bringing together a carbon disulphide solution of iodine and metallic tin. Carbon tetrachloride may, however, be advantageously substituted for carbon disulphide, owing to the fact that stannic iodide is much more soluble in this solvent at its boiling-point than at ordinary temperature, and, therefore, separates on cooling. The iodide may also be obtained by precipitating a concentrated solution of stannic chloride with potassium iodide. It is a bright red, crystalline powder consisting of regular octahedra; after sublimation, however, it appears in yellowish red needles. This compound melts at 143.5° C., and boils at 340° C., though it is said to sublime at 180° C. It may be dissolved in carbon disulphide, alcohol, ether, chloroform, benzene, and arsenic tribromide. Cryoscopic determinations of the molecular weight of stannic iodide in the last-named solvent yield abnormal results, of which various explanations have been given.

Stannic iodide does not give a clear solution with water on account of hydrolysis; it forms with ammonia three additive compounds: SnI4.3NH3, SnI4.4NH3, SnI4.6NH3 (Personne), which are produced by the action of ammonia on a solution of the iodide in carbon disulphide or ether. The first compound is yellow; the other two are white. They are all volatile and are decomposed by water into ammonia, ammonium iodide, and stannic oxide. The compound SnI4.8NH3 has also been prepared.

Iodostannic Acid cannot be formed in aqueous solution on account of the hydrolysis of stannic iodide, which is much more complete than that of the chloride. Pyridine stanni-iodide, (C5H5NH)2SnI6, is formed in bluish black needles when an alcoholic solution of pyridine hydriodide is added to a solution of stannic iodide in alcoholic hydrogen iodide. The quinoline salt is similarly obtained.


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