Chemical elements
  Uranium
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
    Compounds
      Uranium Difluoride
      Uranium Tetrafluoride
      Uranous Oxyfluoride
      Uranium Hexafluoride
      Uranyl Fluoride
      Uranium Trichloride
      Uranium Tetrachloride
      Uranium Pentachloride
      Uranyl Chloride
      Uranyl Chlorate
      Uranyl Perchlorate
      Uranium Tetrabromide
      Uranyl Bromide
      Uranium Tetra-iodide
      Uranyl Iodide
      Uranyl Iodate
      Uranous Oxide
      Uranous Hydroxide
      Uranium Pentoxide
      Urano-uranic Oxide
      Uranium Trioxide
      Ammonium Diuranate
      Ammonium Hexa-uranate
      Hydroxylamine Uranate
      Hydroxylamine Potassio-uranate
      Barium Uranate
      Barium Diuranate
      Bismuth Uranate
      Iron Uranate
      Lithium Uranate
      Potassium Uranate
      Potassium Diuranate
      Potassium Tetra-uranate
      Potassium Hexa-uranate
      Rubidium Uranate
      Silver Diuranate
      Sodium Uranate
      Sodium Diuranate
      Sodium Triuranate
      Sodium Penta-uranate
      Strontium Uranate
      Zinc Uranate
      Peruranic acid
      Ammonium Peruranate
      Barium Peruranates
      Lithium Peruranate
      Nickel Peruranate
      Potassium Peruranate
      Sodium Peruranates
      Uranium Monosulphide
      Uranium Sesquisulphide
      Uranium Disulphide
      Uranium Oxysulphide
      Uranyl Sulphide
      Uranium Sulphite
      Uranyl Sulphite
      Complex Uranyl Sulphites
      Uranium Sulphate
      Uranium Dithionates
      Uranyl Sulphate
      Uranyl Pyrosulphate
      Uranyl Thiosulphate
      Uranyl Dithionate
      Uranium Sesquiselenide
      Uranium Diselenide
      Uranyl Selenide
      Uranyl Selenite
      Uranyl Selenate
      Uranium Telluride
      Uranium Nitrides
      Uranous Nitrate
      Uranyl Nitrate
      Uranium Monophosphide
      Uranous Phosphide
      Uranyl Hypophosphite
      Uranyl Phosphite
      Uranous Phosphates
      Uranyl Phosphates
      Complex Uranyl Phosphates
      Uranyl Aminophosphates
      Uranous Arsenide
      Uranyl Metarsenite
      Uranous Arsenate
      Uranyl Arsenates
      Complex Uranyl Arsenates
      Uranous Antimonide
      Uranous Antimonate
      Uranium Carbide
      Complex Uranyl Carbonates
      Ammonium Uranyl Carbonate
      Calcium Uranyl Carbonate
      Potassium Uranyl Carbonate
      Sodium Uranyl Carbonate
      Thallium Uranyl Carbonate
      Potassium Uranyl Ferrocyanide
      Uranyl Platinocyanide
      Uranyl Cyanate
      Uranyl Thiocyanate
      Uranium Silicide
      Uranium Boride
      Uranyl Perborate
    PDB 1anv-3pu4

Uranyl Sulphide, UO2S






Uranyl Sulphide, UO2S, is obtained by adding ammonium sulphide to an alcoholic solution of a uranyl salt, washing the precipitate with alcohol and drying in a vacuum. Precipitation from aqueous solutions yields a brown amorphous hydrated form, which is soluble in dilute acids, including acetic acid, and also in ammonium carbonate. Complete precipitation is obtained only after prolonged warming of the mixture containing a slight excess of ammonium sulphide; the precipitate then becomes olive green, crystalline, and can be easily filtered, but it consists largely of hydrated uranous oxide and sulphur, due to hydrolytic decomposition by the warm water. Uranyl sulphide is obtained as black, tetragonal, needle-shaped crystals by fusing together pure dry potassium thiocyanate (12 parts), urano-uranic oxide (3 parts), and flowers of sulphur (5 parts). It rapidly decomposes on heating, leaving a residue of the green oxide.

If uranyl sulphide, freshly precipitated from aqueous solution, is digested for two days with excess of ammonium sulphide, the mixture being in contact with air, a deep red solid of complex composition, and known as uranium red is produced. It has been shown by Kohlschutter that a series of similar red compounds may be obtained by reducing solutions of alkali uranates, containing excess of uranyl sulphate or nitrate and a little free alkali, by means of hydrogen sulphide; in each case an orange-yellow compound is first produced, which on treatment with alkali yields a blood-red uranium red. This is decomposed by acids, with liberation of hydrogen sulphide and sulphur. The composition of the orange-yellow substance appears to be 5UO3.2K2O.H2S2, while that of the potassium uranium-red corresponds to 5UO3.2K2O.HKS2. Thus all the uranium is in the hexavalent condition, and from a study of the two compounds on decomposition, Kohlschutter suggests the following constitutional formulae:

1. Orange-red parent compound.2. Uranium red.
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