Chemical elements
  Tungsten
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      Tungsten Hexafluoride
      Tungsten Oxyfluorides
      Tungsten Dichloride
      Double Chlorides of Trivalent Tungsten
      Tungsten Tetrachloride
      Tungsten Pentachloride
      Tungsten Hexachloride
      Tungsten Oxychlorides
      Tungsten Dibromide
      Tungsten Pentabromide
      Tungsten Hexabromide
      Tungsten Chlorobromides
      Tungsten Oxybromides
      Tungsten Di-iodide
      Tungsten Tetra-iodide
      Tungsten Dioxide
      Ditungsten Pentoxide
      Tungsten Trioxide
      Tungstic Acid
      Aluminium Tungstates
      Ammonium Tungstates
      Antimony Tungstates
      Barium Tungstates
      Normal Bismuth Tungstate
      Cadmium Tungstates
      Calcium Tungstates
      Cerium Tungstate
      Chromium Tungstates
      Cobalt Tungstates
      Copper Tungstates
      Indium Tungstate
      Iron Tungstates
      Lanthanum Tungstate
      Lead Tungstates
      Lithium Tungstates
      Magnesium Tungstates
      Manganese Tungstates
      Mercury Tungstates
      Neodymium Tungstate
      Nickel Tungstates
      Platinum Tungstates
      Potassium Tungstates
      Praseodymium Tungstate
      Rubidium Tungstates
      Samarium Tungstate
      Silver Tungstates
      Sodium Tungstates
      Strontium Tungstates
      Thallium Tungstates
      Tin Tungstates
      Uranium Tungstate
      Ytterbium Tungstates
      Yttrium Tungstate
      Zinc Tungstates
      Metatungstic Acid
      Ammonium Metatungstate
      Barium Metatungstate
      Cadmium Metatungstate
      Calcium Metatungstate
      Cerium Metatungstate
      Cobalt Metatungstate
      Lead Metatungstate
      Magnesium Metatungstate
      Mercurous Metatungstate
      Nickel Metatungstate
      Potassium Metatungstate
      Rubidium Metatungstate
      Samarium Metatungstate
      Silver Metatungstate
      Sodium Metatungstate
      Strontium Metatungstate
      Thallous Metatungstate
      Zinc Metatungstate
      Pertungstic Acid
      Tungsten Bronzes
      Potassium Tungsten Bronze
      Lithium Tungsten Bronze
      Lithium Potassium Tungsten Bronze
      Sodium tungsten bronzes
      Tungsten Disulphide
      Tungsten Trisulphide
      Thiotungstates
      Tungsten Diselenide
      Tungsten Triselenide
      Tungsten Phosphides
      Tungsten Diphosphide
      Tritungsten Tetraphosphide
      Tungsten Monophosphide
      Tungsten Subphosphide
      Phosphotungstic Acids
      12-Tungstophosphoric Acid
      11-Tungstophosphates
      21:2-Tungstophosphoric Acid
      10-Tungstophosphoric Acid
      9-Tungstophosphoric Acid
      17:2-Tungstophosphates
      3-Tungstophosphates
      Hypophosphotungstates
      Tungsten Diarsenide
      Tungsten Chloro-arsenide
      12-Tungsto-arsenates
      11-Tungsto-arsenates
      9-Tungsto-arsenic Acid
      17:2-Tungsto-arsenates
      Tungsto-arsenites
      Tritungsten Carbide
      Ditungsten Carbide
      Tungsten Monocarbide
      Tungsten Iron Carbides
      Tungstocyanic Acid
      Ammonium Tungstocyanide
      Calcium Tungstocyanide
      Cadmium Tungstocyanide
      Caesium Tungstocyanide
      Lead Tungstocyanide
      Magnesium Tungstocyanide
      Manganese Tungstocyanide
      Potassium Tungstocyanide
      Rubidium Tungstocyanide
      Silver Tungstocyanide
      Sodium Tungstocyanide
      Strontium Tungstocyanide
      Thallium Tungstocyanide
      Zinc Tungstocyanide
      Tungsticyanic Acid
      Tungsten Sesquisilicide
      Tungsten Disilicide
      Tungsten Trisilicide
      12-Tungstosilicic Acid
      Iso-12-tungstosilicic Acid
      10-Tungstosilicates
      Tungsten Boride
      12-Tungstoboric Acid
      Iso-12-tungstoboric Acid
    Alloys
    PDB 1aor-2rav
    PDB 2rb5-6fit

11-Tungstophosphates






11-Tungstophosphates (P2O5:WO3 = 1:22) - The free acid corresponding to this series of salts has not been isolated. The salts are very stable and are obtained by careful hydrolysis of the 12-tungstophosphates. If barium carbonate is added to a 30 per cent, solution of 12-tungstophosphoric acid until a faint turbidity appears, on concentration a white barium salt separates which may be recrystallised from solution in dilute acetic acid. The crystals obtained are of composition 7BaO.P2O5.22WO3.54H2O.

The potassium salt, 7K2O.P2O5.22WO3.3H2O, may be obtained in a similar manner by adding potassium carbonate to a suspension of the potassium 12-tungstophosphate until a clear solution is obtained.

The sodium salt, 7Na2O.P2O5.22WO3.33H2O, is best prepared by adding sodium sulphate to a solution of the barium salt. On evaporating the filtered solution a mass of needle-shaped crystals is obtained.

These salts are all soluble in water, and the solutions react neutral to litmus. Acid salts of this series have not been obtained. The addition of strong mineral acids to 11-tungstophosphates causes decomposition into the 12-tungstophosphate and the 21:2-tungstophosphate; the following formula has therefore been suggested as an expression of their constitution:

R7[P(OH)(W2O7)5]-W2O7-[(W2O7)5(OH)P]R7.xH2O.

The molecule is thus considered to contain two nuclei joined by an outer bridge.

The following well-crystallised double salts have been prepared by addition of simple metallic salts to solutions of 11-tungstophosphates:

4BaO.3Ag2O.P2O5.22WO3.34H2O,
5BaO.2K2O.P2O5.22WO3.48H2O.

A series of salts obtained by the addition of hydrochloric acid to mixtures of alkali tungstates and alkali phosphates have been described by Gibbs, who formulates them, 3R2O.P2O5.22WO3.xH2O. From their mode of preparation and reactions these salts appear to be more related to the 12-tungstophosphates than to the salts just described. Their composition, however, is not established.


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