Chemical elements
    Physical Properties
    Chemical Properties
      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 Fluoride, UO2F2

Uranyl Fluoride, UO2F2, is formed with uranous oxyfluoride (see above) by the action of hydrofluoric acid on urano-uranic oxide:

U3O8 + 6HF = UOF2 + 2UO2F2 + 3H2O.

The green insoluble uranous oxyfluoride is removed by filtration, and the uranyl fluoride remains as a yellow mass after evaporation of the solution. It is also obtained as a yellow powder by repeated evaporation of uranyl acetate with hydrofluoric acid. A white crystalline form has been described by Smithells, who obtained it by carefully heating the tetrafluoride in air; it dissolved in water yielding a yellow solution.

Complex uranyl fluorides of the type UO2F2.3RF (R = K, NH4) have been obtained by the addition of excess of the alkali fluoride to a solution of uranyl fluoride, both the yellow and the white variety acting in this way. A solution of uranyl acetate, or of potassium diuranate containing hydrofluoric acid, with excess of the alkali fluoride, also yields the same compounds. The potassium salt, UO2F2.3KF, separates as a heavy orange-yellow crystalline precipitate; it is dimorphous, and the crystals may be tetragonal or monoclinic according to the method of preparation. At 20° C. the crystals have density 4.263. The addition of excess of hydrogen peroxide to a solution of this salt gives a yellow solution from which a yellow peroxyfluoride, of composition 3(UO4.KF).UO3F2.KF.4H2O, separates on keeping. The ammonium salt, UO2F2.3NH4F, only yields crystals of the tetragonal form, the density of which at 20° C. is 3.186.

If the potassium salt is dissolved in water containing not more than 13 per cent, of the acid fluoride of potassium, the solution on concentration yields triclinic crystals of the compound 2UO2F2.5KF. If excess of uranyl nitrate is present in the solution, monoclinic crystals of the compound 2UO2F2.3KF are obtained.

A soluble uranyl silicofluoride has been described.

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