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 Phosphates






Well-defined ortho- and pyro-phosphates exist, but little is known of uranyl metaphosphate. Several complex uranyl phosphates have been described.


Uranyl Orthophosphates

The normal salt, (UO2)3(PO4)2, is formed, according to Werther, as a yellow precipitate when a solution of the normal sodium phosphate is poured into a neutral solution of uranyl nitrate. Uranyl monohydrogen phosphate, UO2HPO4, is obtained as a yellow amorphous precipitate by adding phosphoric acid, or a soluble phosphate, to a solution of uranyl acetate or nitrate; or by treating uranyl hydroxide with phosphoric acid. If the precipitate is boiled for some considerable time with dilute hydrochloric acid, it becomes converted into tetragonal crystals of composition UO2HPO4.4H2O. A trihydrate, UO2HPO4.3H2O, is also obtained 3 by the addition of sodium dihydrogen phosphate on an acid solution of uranyl nitrate; it separates as a sulphur-yellow crystalline powder. The ammonium salt, UO2(NH4)PO4.xH2O, is formed when a soluble phosphate is added to a solution containing an ammonium and a uranyl salt. The greenish-yellow precipitate is quite insoluble in presence of acetic acid or ammonium acetate, so that the precipitation is quantitative, and is therefore employed in the volumetric estimation of phosphates, with potassium ferrocyanide or cochineal as indicator. Upon ignition the precipitate is converted to uranyl pyrophosphate, (UO2)2P2O7.

By cooling a hot concentrated solution of uranyl monohydrogen phosphate in nitric acid, a phosphonitrate of composition UO2HPO4.HNO3.7H2O, or 2UO3.P2O5.N2O5.16H2O, separates. This is decomposed by water with separation of nitric acid.

Uranyl dihydrogen phosphate

Uranyl dihydrogen phosphate, UO2(H2PO4)2.3H2O, is obtained by concentrating a solution of uranic oxide in hot dilute phosphoric acid; it separates in small yellow crystals.

Uranyl metaphosphate

Uranyl metaphosphate, UO2(PO3)2, is obtained, according to Rammelsberg, by heating the yellowish-green precipitate produced by the action of nitric acid on uranyl hypophosphite.

Uranyl pyrophosphate

Uranyl pyrophosphate, (UO2)2P2O7, is formed as a precipitate when a solution of sodium metaphosphate is poured into a hot solution of uranyl nitrate. The tetrahydrate, (UO2)2P2O7.4H2O, is precipitated in yellow microcrystals by double decomposition of sodium pyrophosphate and uranyl nitrate. The hydrate loses water and yields the anhydrous salt at 120° C. Uranyl pyrophosphate is insoluble in water, alcohol, or ether; but it dissolves in excess of sodium pyrophosphate solution, and also in dilute nitric acid.
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