Chemical elements
  Lead
    Occurrence
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
      Lead Tetramethyl
      Lead Tetraethyl
      Lead Tetraphenyl
      Lead Ethoxide
      Lead Fluoride
      Lead Tetrafluoride
      Hydrofluoplumbic Acid
      Lead Chloride
      Lead Chloride Double Salts
      Basic Lead Chlorides
      Lead Tetrachloride
      Ammonium Plumbichloride
      Lead Chlorite
      Lead Chlorate
      Lead Perchlorate
      Lead Dibromide
      Double Salts of Lead Bromide
      Basic Lead Bromides
      Lead Bromate
      Lead Iodide
      Lead Iodide Complex Salts
      Basic Lead Iodides
      Lead Tetra-iodide
      Lead Iodate
      Lead Periodates
      Lead Suboxide
      Lead Monoxide
      Litharge
      Massicot
      Lead Hydroxides
      Lead Dioxide
      Plumbic Acids
      Hexahydroxyplumbic Acid
      Colloidal Plumbic Acid
      Potassium Plumbate
      Lead Plumbate
      Calcium Orthoplumbate
      Lead Orthoplumbate
      Red Lead
      Metaplumbic Acid
      Calcium Metaplumbate
      Lead Metaplumbate
      Basic Lead Plumbate
      Lead Sulphide
      Lead Sulphohalides
      Lead Polysulphide
      Lead Sulphite
      Lead Sulphates
      Lead Sulphate
      Basic Lead Sulphates
      Lead Hydrogen Sulphate
      Plumbic Sulphate
      Lead Persulphate
      Lead Thiosulphate
      Lead Dithionate
      Lead Selenide
      Lead Selenite
      Lead Selenate
      Lead Telluride
      Lead Tellurite
      Lead Azide
      Lead Azoimide
      Lead Hydrazoate
      Lead Imide
      Lead Hyponitrite
      Lead Nitrites
      Lead Nitrate
      Lead saltpetre
      Basic Lead Nitrates
      Lead Hypophosphite
      Lead Phosphite
      Lead Orthophosphate
      Lead Monohydrogen Phosphate
      Lead Dihydrogen Phosphate
      Lead Pyrophosphate
      Lead Metaphosphate
      Lead Arsenite
      Lead Orthoarsenate
      Lead Hydrogen Arsenate
      Lead Pyroarsenate
      Lead Antimonate
      Lead Carbonate
      White Lead
      Lead Formate
      Lead Acetate
      Sugar of Lead
      Complex Lead Acetates
      Plumbic Acetate
      Lead Tetra-acetate
      Lead Oxalate
      Lead Tartrate
      Lead Silicates
      Lead Borates
      Normal Lead Chromate
      Lead Dichromate
      Basic Lead Chromate
      Lead Molybdate
      Lead Tungstate
      Lead Metatungstate
      Lead Diuranate
      Lead Peruranate
    PDB 1afv-3qjk

Lead Suboxide, Pb2O






Berzelius first observed that when lead is heated below its melting-point in the air its surface becomes covered with a grey film, which appears to be the Lead Suboxide, Pb2O. It was later discovered by Dulong that when lead oxalate is heated to 300° C. out of contact with air it yields the suboxide by the reaction

2PbC2O4 Pb2O + 3CO2 + CO.

Later observers thought this product was merely a mixture of lead monoxide and metallic lead; but Tanatar has proved that the suboxide is undoubtedly formed by the above reaction, carried out in an atmosphere of carbon dioxide or nitrogen, provided the temperature is kept as low as possible. The product is then a greyish black powder of density 8.342 at 18° C., which is unaltered by dry air or water, but is converted into the monoxide and metallic lead by dilute acids and alkalis. Moreover, the heat of solution of 1 gram-molecule of this substance in acetic acid is 10,048 calories, whilst that of 1 gram-molecule of lead monoxide is 15,500 calories. If, however, the temperature at which lead oxalate is decomposed is too high, a greyish green product results whose molecular heat of solution in acetic acid is 15,500 calories. This product must, therefore, be a mixture of lead monoxide and lead, into which the suboxide is decomposed at high temperature with absorption of 5,452 calories.

The suboxide is also formed by the reduction of the mmioxide by hydrogen at a temperature not exceeding 235° C. Furaier proof that the dark grey powder is not a mixture of lead monoxide and lead is furnished by the fact that mercury dissolves no lead from it, nor sugar solution any lead monoxide. After the powder has been sufficiently heated, however, sugar solution extracts lead monoxide from it, leaving metallic lead behind.


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