Chemical elements
  Phosphorus
    Isotopes
    Energy
    Preparation
    Applications
    Physical Properties
    Chemical Properties
      Alkali Phosphides
      Alkaline Earth Phosphides
      Copper Silver and Gold Phosphides
      Zinc Group Phosphides
      Aluminium Phosphide
      Titanium Group Phosphides
      Tin Phosphides
      Lead Phosphides
      Arsenic Phosphides
      Antimony Phosphides
      Bismuth Phosphides
      Chromium Phosphides
      Molybdenum and Tungsten Phosphides
      Manganese Phosphides
      Iron Phosphides
      Cobalt Phosphides
      Phosphonium Chloride
      Phosphonium Bromide
      Phosphonium Iodide
      Hydrogen Phosphides
      Alkylphosphines
      Phosphorus Trifluoride
      Phosphorus Pentafluoride
      Phosphorus Trifluorodichloride
      Phosphorus Trifluorodibromide
      Fluophosphoric Acid
      Phosphorus Dichloride
      Phosphorus Trichloride
      Phosphorus Pentachloride
      Phosphorus Chlorobromides
      Phosphorus Chloroiodides
      Phosphorus Tribromide
      Phosphorus Pentabromide
      Phosphorus Diiodide
      Phosphorus Triiodide
      Phosphorus Oxytrifluoride
      Phosphorus Oxychloride
      Pyrophosphoryl Chloride
      Metaphosphoryl Chloride
      Phosphoryl Monochloride
      Phosphoryl Dichlorobromide
      Phosphoryl Chlorodibromide
      Phosphoryl Tribromide
      Metaphosphoryl Bromide
      Phosphoryl Oxyiodides
      Phosphorus Thiotrifluoride
      Phosphorus Thiotrichloride
      Phosphorus Thiotribromide
      Mixed Phosphorus Thiotrihalides
      Phosphorus Suboxides
      Phosphorus Trioxide
      Phosphorus Dioxide
      Phosphorus Pentoxide
      Hypophosphorous Acid
      Phosphorous Acid
      Meta- and Pyro-phosphorous Acids
      Hypophosphoric Acid
      Tetraphosphorus Trisulphide
      Diphosphorus Trisulphide
      Tetraphosphorus Heptasulphide
      Phosphorus Pentasulphide
      Phosphorus Oxysulphides
      Phosphorus Thiophosphites
      Phosphorus Thiophosphates
      Phosphorus Selenophosphates
      Phosphorus Sulphoselenides
      Diamidophosphorous Acid
      Phosphorus Triamide
      Monamidophosphoric Acid
      Diamidophosphoric Acid
      Triamidophosphoric Acid
      Dimetaphosphimic Acid ≡P=
      Trimetaphosphimic Acid
      Tetrametaphosphimic Acid
      Penta- and Hexametaphosphimic Acid
      Monamidodiphosphoric Acid
      Diamidodiphosphoric Acid
      Triamidodiphosphoric Acid
      Nitrilotrimetaphosphoric acid
      Monothioamidophosphoric Acids
      Thiophosphoryl Nitride
      Di- Tri-imido- and -amido-thiophosphates
      Imidotrithiophosphoric Acid =
      Phosphorus Chloronitrides
      Triphosphonitrilic Chloride
      Tetraphosphonitrilic Chloride
      Pentaphosphonitrilic Chloride
      Hexaphosphonitrilic Chloride
      Heptaphosphonitrilic Chloride
      Triphosphonitrilic Bromide
      Phosphorus Halonitrides
      Phosphorus Nitride
      Phosphine
      Pyrophosphoric Acid
      Phosphoric acids
    Slow Oxidation
    Phosphatic Fertilisers

Phosphorus Dioxide, [PO2]n






Phosphorus Dioxide, [PO2]n, or Tetroxide, P2O4.—The formula P2O4 is sometimes assigned to this oxide by analogy with N2O4, but by analogy with the other oxides of phosphorus the formula would be P4O8.

By heating in a sealed evacuated tube the products of the slow combustion of phosphorus, a crystalline sublimate is obtained, which was shown by Thorpe and Tutton to be a distinct new oxide, probably formed according to the equation

P4O6 = 3PO2 + P

The oxide may also be formed directly by slow oxidation of phosphorus in oxygen at a pressure of 600 mm. and containing water vapour (0.1 mm.).

It sublimes at about 180° C. in colourless crystals which are of rhombic appearance. The density, D14°22.6°, is 2.537. The vapour density, determined at a temperature above 1400° C., corresponded to a molecular weight of 458.6, and therefore to the formula P8O16. This oxide is stable in oxygen at the ordinary temperature, but is oxidised to pentoxide at 350° to 400° C.

As the tetroxide has been shown to have the formula of a " mixed anhydride," it should yield phosphorous and phosphoric acids on treatment with water. Actually, the solution, after neutralisation with sodium hydroxide, showed the reactions of phosphites and meta- phosphates. The hydration may therefore be represented by an equation

2PO2 + 2H2O = H3PO3 + HPO3


© Copyright 2008-2012 by atomistry.com