Chemical elements
    Physical Properties
    Chemical Properties
      Platinum Difluoride
      Platinum Tetrafluoride
      Platinum Dichloride
      Tetrachlor~platinous Acid
      Potassium Tetrachlor-platinite
      Trichlor-hydroxy-platinous Acid
      Silver Trichlor-hydroxy-platinite
      Platinum Trichloride
      Caesium Pentachlor-platinite
      Platinum Tetrachloride
      Ammonium Chlor-platinate
      Caesium Chlor-platinate
      Potassium Chlor-platinate
      Rubidium Chlor-platinate
      Silver Chlor-platinate
      Sodium Chlor-platinate
      Pentachlor-hydroxy-platinic Acid
      Barium Pentachlor-hydroxy-platinate
      Silver Pentachlor hydroxy-platinate
      Tetrachlor-dihydroxy-platinic Acid
      Dichlor-tetrahydroxy-platinic Acid
      Monochlor-pentahydroxy-platinic Acid
      Platinum Dibromide
      Brom platinous Acid
      Brom-platinic Acid
      Platinum Di-iodide
      Platinum Tetra-iodide
      Iodo-platinic Acid
      Ammonium Iodoplatinate
      Potassium Iodo-platinate
      Sodium Iodo-platinate
      Tetra-iodo-dihydroxy-platinic Acid
      Platinum Monoxide
      Triplatinum Tetroxide
      Platinum Sesquioxide
      Platinum Dioxide
      Hexahydroxy-platinic Acid
      Platinum Trioxide
      Platinum Monosulphide
      Platinum Sesquisulphide
      Platinum Disulphide
      Potassium Thio-platinate
      Platinum Oxysulphide
      Platinum Disulphate
      Platinum Monoselenide
      Platinum Triselenide
      Platinum Subtelluride
      Platinum Monotelluride
      Platinum Ditelluride
      Ammonium Platinonitrite
      Potassium Platinonitrite
      Silver Platinonitrite
      Platinum Subphosphide
      Platinum Monophosphide
      Platinum Diphosphide
      Platinum Arsenide
      Platinum Di-antimonide
      Monocarbonyl Platinum Dichloride
      Sesquicarbonyl Platinum Dichloride
      Dicarbonyl Platinum Dichloride
      Diphosgene Platinum Dichloride
      Carbonyl Platinum Dibromide
      Monocarbonyl Platinum Di-iodide
      Carbonyl Platinum Monoxide
      Carbonyl Platinum Monosulphide
      Carbonyl Platinum Thiocyanate
      Platinous Cyanide
      Cyanoplatinous Acid
      Aluminium Platinocyanide
      Ammonium Platinocyanide
      Barium Platinocyanide
      Calcium Platinocyanide
      Cerium Platinocyanide
      Copper Platinocyanide
      Hydrazine Platinocyanide
      Hydroxylamine Platinocyanide
      Indium Platinocyanide
      Lead Platinocyanide
      Magnesium Platinocyanide
      Potassium Platinocyanide
      Radium Barium Platinocyanide
      Rubidium Platinocyanide
      Sodium Platinocyanide
      Sodium Potassium Platinocyanide
      Strontium Platinocyanide
      Uranyl Platinocyanide
      Dichlorcyanoplatinic Acid
      Cyanoplatinic Acid
      Lithium Platinicyanide
      Potassium Platinicyanide
      Silver Platinicyanide
      Potassium Thiocyanoplatinite
      Ammonium Thiocyanoplatinate
      Potassium Thiocyanoplatinate
      Potassium Selenocyanoplatinate
      Platinum Subsilicide
      Platinum Monosilicide
    PDB 1a2e-2bho
    PDB 2ch8-3un9
    PDB 3vdk-5bna

Tetrachlor-platinites, M2PtCl4

Salts of tetrachlor-platinous acid are known as tetrachlor-platinites, and have the general formula M2PtCl4.

They are both stable and well known. They may be prepared in a variety of ways, chief amongst which are:
  1. Addition of chlor-platinous acid or a solution of platinous chloride to a metallic carbonate or chloride. For this purpose the chlor-platinous acid is best made by dissolving platinous chloride in hydrochloric acid. This ensures the freedom of the final product from the metallic chlor-platinate. A less troublesome method is to reduce chlor-platinic acid with sulphur dioxide if a pure product is not required, but this is not easy to carry out satisfactorily otherwise. If, for example, reduction of the chlor-platinic acid is not complete, the metallic platinite will be contaminated with platinate. If, on the other hand, excess of sulphur dioxide is present, the metallic chlor-platinite becomes contaminated with sulphite derivatives.
  2. Probably the most convenient method of preparing metallic chlor-platinites consists in reducing the corresponding chlor-platinates. This may be effected with potassium oxalate in concentrated aqueous solution at the boiling-point, and containing a trace of iridium, the reaction proceeding according to the equation:

    M2PtCl6 + K2C2O4 = M2PtCl4 + 2KCl + 2CO2.

    Hydrogen sulphide, cuprous chloride, and the last named along with powdered zinc, have been used as reducing agents, but are open to several objections.
  3. Double decomposition of metallic sulphates and barium chlor- platinite. Thus:

    M2SO4 + BaPtCl4 = BaSO4 + M2PtCl4.

The clear solution containing the soluble chlor-platinite is decanted or filtered free from the insoluble barium sulphate, and concentrated.

The chlor-platinites are mostly soluble salts yielding red solutions readily distinguished from solutions of the chlor-platinates, which are yellow. The silver, lead, mercury, and thallium salts are almost insoluble in water.

Chlor-platinites are oxidised by chlorine and by hypochlorites to chlor-platinates, whilst nascent hydrogen reduces them in aqueous solution with separation of metallic platinum.

When their solutions are warmed and a current of hydrogen sulphide is passed through, platinous sulphide is obtained as a black precipitate; whilst sulphur dioxide under like conditions effects their decolorisation, platinosulphites being produced. With ammonia, ammino derivatives are obtained.

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