Chemical elements
  Platinum
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    Physical Properties
    Chemical Properties
      Platinum Difluoride
      Platinum Tetrafluoride
      Platinum Dichloride
      Tetrachlor~platinous Acid
      Tetrachlor-platinites
      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
      Platinocyanides
      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
    Catalyst
    PDB 1a2e-2bho
    PDB 2ch8-3un9
    PDB 3vdk-5bna

Brom platinous Acid, H2PtBr4






Brom platinous Acid, H2PtBr4, has not been isolated in the pure state, but exists in solution when platinous bromide is dissolved in aqueous hydrogen bromide. It combines with bases to form:


Brom-platinites, M2PtBr4

Of these the most important salt is:

Potassium Tetrabrom-platinite, K2PtBr4

Potassium Tetrabrom-platinite, K2PtBr4.2H2O, which may be obtained by reduction of the hexabrom-platinate, K2PtBr6, with potassium oxalate solution at 100° C., or by addition of sodium bromide to potassium tetrachlor-platinite.

On concentration, the brom-platinite crystallises out in large, black, rhombic crystals:

a: b: с = 0.60582: 1: 0.70499.

The crystals are readily soluble in water. Their heat of formation is as follows:

[Pt] + Br2 + 2KBr.Aq. = K2PtBr4.Aq. + 21.83 Cals.

The heat of solution of the crystals is:

[K2PtBr4] + Aq. = K2PtBr4.Aq. - 10.6 Cals.

Platinum Tetrabromide, PtBr4

Platinic Bromide, Platinum Tetrabromide, PtBr4 is obtained by maintaining brom-platinic acid at 180° C. in air. The product is not pure, for even at this temperature it undergoes partial dissociation into the dibromide:

PtBr4PtBr2 + Br2.

As obtained in this way, platinic bromide is a dark powder, slightly soluble in water to a reddish brown solution which contains dihydroxy-tetrabrom-platinic acid, H2PtBr4(OH)2. It is fairly soluble in a mixture of alcohol and water, and very soluble both in alcohol and in ether. On warming, however, these latter solutions become reduced, yielding a deposit of platinum black. Its solution in aqueous hydrogen bromide contains brom-platinic acid.

The salt has not as yet been obtained in a perfectly pure condition. Its heat of formation is given by Pigeon:

[Pt] + 2Br2 = [PtBr4] + 42.4 Cals.

[Pt] + 2(Br2) = [PtBr4] + 56.8 Cals.
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