Chemical elements
  Vanadium
    Isotopes
    Energy
    Preparation
    Applications
    Physical Properties
    Chemical Properties
      Hypovanadous Oxide
      Vanadous Oxide
      Hypovanadic Oxide
      Vanadic Oxide
      Hypovanadous Fluoride
      Vanadous Fluoride
      Vanadium Tetrafluoride
      Vanadium Pentafluoride
      Vanadyl Difluoride
      Vanadium Oxytrifluoride
      Vanadium Dioxyfluoride
      Hypovanadous Chloride
      Vanadous Chloride
      Hypovanadic Chloride
      Divanadyl Chloride
      Vanadium Oxymonochloride
      Vanadyl Dichloride
      Vanadium Oxytrichloride
      Vanadium Oxydichloride
      Vanadous Bromide
      Hypovanadic Bromide
      Vanadium Oxymonobromide
      Vanadyl Dibromide
      Vanadium Oxytribromide
      Hydrated Vanadium Tri-iodide
      Vanadium Suboxide
      Hypovanadous Oxide
      Vanadous Oxide
      Hypovanadic Oxide
      Hypovanadates
      Intermediate Vanadium Oxides
      Vanado-vanadates
      Vanadium Pentoxide
      Orthovanadates
      Sodium Stannovanadates
      Vanadates
      Pyrovanadates
      Metavanadates
      Polyvanadates
      Double Vanadates
      Heteropoly-Acids with Vanadium
      Vanado-phosphates
      Molybdo-vanadophosphates
      Vanado-arsenates
      Molybdo-vanadoarsenates
      Tungsto-vanadoarsenates
      Molybdo-vanadates
      Tungsto-vanadates
      Uranyl-vanadates
      Molybdo-vanadosilicates
      Tungsto-vanadosilicates
      Vanado-selenites
      Vanado-tellurites
      Vanado-iodates
      Vanado-periodates
      Oxalo-vanadates
      Pervanadic Acid
      Pyropervanadates
      Orthopervanadates
      Vanadium Monosulphide
      Vanadium Trisulphide
      Vanadium Pentasulphide
      Vanadium Oxysulphides
      Hypovanadous Sulphate
      Vanadous Sulphate
      Vanadyl Sulphites
      Vanadyl Sulphates
      Vanadic Sulphates
      Vanadyl Dithionate
      Ammonium Orthothiovanadate
      Ammonium Pyroxyhexathiovanadate
      Sodium Orthoxytrithiovanadate
      Sodium Orthoxymonothiovanadate
      Vanadium Selenides
      Vanadyl Selenite
      Vanadyl Selenates
      Vanadium Subnitride
      Vanadium Mononitride
      Vanadium Dinitride
      Alkali Vanadyl Nitrites
      Vanadium Nitrates
      Vanadyl Hypophosphite
      Vanadyl Phosphates
      Vanadous Pyrophosphate
      Vanadyl Arsenates
      Vanadium Carbide
      Vanadyl Cyanide
      Potassium Vanadocyanide
      Potassium Vanadicyanide
      Vanadium Ferrocyanides
      Ammonium Vanadyl Thiocyanate
      Vanadium Subsilicide
      Vanadium Disilicide
      Vanadium Boride
    Detection, Estimation
    PDB 1b8j-2i4e
    PDB 2jhr-6rsa

Double Vanadates






Vanadium pentoxide exhibits a strong tendency to combine with two or more bases to produce well-crystallised double salts. Their general method of preparation consists in adding a solution of a salt of the required metal to a solution of an alkali vanadate; concentration of the mother-liquor after precipitation of the simple vanadate gives rise to a vanadate which is found to contain both the alkali base and the metallic base. Frequently from the same two bases and vanadic acid a series of such double vanadates can be prepared in which the relative proportions of basic oxides and vanadic acid vary. The decomposition of ammonium metavanadate with acetic acid in the presence of sodium silicate yields glistening red crystals of the composition 2(NH4)2O.Na2O.5V2O5.15H2O. The molecular proportions in this compound are simple, but a large number of double vanadates have been prepared in which the molecular proportions are by no means simple. Thus, by the action of two molecular proportions of ammonium chloride on a boiling, concentrated solution of one molecular proportion of sodium metavanadate, yellowish-red prisms of composition 4[(NH4)12/11.Na10/11]O.7V2O5.17½H2O are obtained. It is a matter of some doubt whether these complex double salts should be looked upon as definite compounds, each having independent existence, or whether each series is not more correctly regarded as composed of isomorphous mixtures of variable composition. The problem is similar to that of the constitution of the salts of the heteropoly-acids, in which vanadium pentoxide is combined with other acid anhydrides.

Other double vanadates which have been prepared are:

2(NH4)2O.2K2O.4V2O5.3H2O or 4NH4VO3.4KVO3.3H2O;
3(NH4)2O.9K2O.20V2O5.52H2O;
2(NH4)2O.K2O.5V2O5.9H2O;
8Na2O.2K2O.18V2O5.35H2O or 4Na4V6O17.K4V6O17.35H2O;
6Na2O.4K2O.15V2O5.30H2O or 3Na4V6O17.2K4V6O17.30H2O;
4K2O.CaO.10V2O5.22H2O;
K2O.3SrO.7V2O5.20H2O and 30H2O;
2K2O.2SrO.7V2O5.18H2O;
K2O.2ZnO.5V2O5.16H2O;
2(4K2O.7V2O5.22½H2O) + 3(4ZnO.7V2O5-22½H2O) or 16K2O.24ZnO.70V2O5.225H2O;
K2O.CdO.3V2O5.9H2O;
3K2O.3CdO.10V2O5.27H2O;
K2O.7MnO.8V2O5.25H2O or 2KVO3.7Mn(VO3)2.25H2O;
K2O.11MnO.12V2O5.48H2O or 2KVO3.11Mn(VO3)2.48H2O;
K2O.2MnO.5V2O5.15H2O and 16H2O;
K2O.5NiO.6V2O5.27H2O or 2KVO3.5Ni(VO3)2.27H2O;
K2O.3NiO.5V2O5.17H2O;
2K2O.4NiO.10V2O5.33H2O;
2K2O.NiO.7V2O5.23H2O;
K2O.2CoO.5V2O5.16H2O and 16½H2O;
K2O.3CoO.7V2O5.21H2O;
2K2O.4CuO.18V2O5.69H2O;
BaO.CdO.3V2O5.9H2O;
3CdO.3ZnO.10V2O5.27H2O.
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