Chemical elements
  Platinum
    Isotopes
    Energy
    Production
    Application
    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

Platinum Dioxide, PtO2






Hydrated Platinum Dioxide, PtO2.xH2O, is obtained1 by boiling platinum tetrachloride with an excess of twice normal sodium hydroxide solution, and then neutralising with acetic acid. The precipitate obtained when the foregoing reactions are carried out in dilute solution, and when the acetic acid is added in the cold, consists of a white deposit of tetrahydrate, PtO2.4H2O. This hydrate is acidic in character, and is probably more correctly represented by the formula H2Pt(OH)6, and is described in further detail under the name of hexahydroxy-platinic acid. It readily loses water, becoming yellow on drying in consequence of partial dehydration. When boiled with water the precipitated tetrahydrate becomes ochre-coloured, being transformed into the trihydrate, PtO2.3H2O. Upon prolonged exposure to sulphuric acid in a desiccator further dehydration ensues, the yellowish brown dihydrate, PtO2.2H2O, being produced. When maintained for some time at 100° C. the mass becomes black and resembles coal in appearance, but yields upon pulverisation a dark brown powder. This is the monohydrate, PtO2.Tl2O, which clings tenaciously to its combined water. It is soluble with difficulty in hydrochloric acid, although, when a portion of the oxide has passed into solution, the remainder dissolves more rapidly on gentle shaking.

On saturating a solution of chlor-platinic acid with hexahydroxy-platinic acid and dialysing, a product is formed which coagulates on warming, and has a composition represented by the formula (PtO2)5.2HCl.9H2O. Boiling water converts it into metaplatinic acid, (PtO2)5.5H2O.

When aqueous solutions of organic acids are boiled with the dioxide, reduction takes place, metallic platinum being deposited, and the acids oxidised. Hydrogen peroxide solution slowly reduces the dioxide.

Platinum dioxide, upon ignition, decomposes, evolving oxygen, a residue of metallic platinum being obtained together with a solid solution of either the monoxide or the sesquioxide in the dioxide.


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