Chemical elements
    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
      Intermediate Vanadium Oxides
      Vanadium Pentoxide
      Sodium Stannovanadates
      Double Vanadates
      Heteropoly-Acids with Vanadium
      Pervanadic Acid
      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


Molybdo-vanadates or Vanado-molybdates. These are obtained in red crystals, rich in vanadium, or yellow powders, poor in vanadium, by dissolving molybdic anhydride, MoO3, in solutions of alkali meta- vanadates, or by acidifying mixed solutions of molybdates and vanadates. A large number of salts have been prepared, which vary considerably in their analytical data. Repetition of the same process of preparation often gives crystals of different composition, so that a definite compound cannot easily be prepared. The salts are usually unstable, and undergo change even on being recrystallised. The same solution may give rise to different salts according to the temperature. Thus, one portion of a solution divided into two parts gave crystals of 2 (NH4)2O.2V2O5.5MoO3.10H2O at 10° C., while at 30° C. the other portion gave crystals of 4(NH4)2O.3V2O5.5MoO3.10H2O. From a study of the system NH4VO3,MoO3; KVO3,MoO3; NaVO3,MoO3, it has been concluded that solutions of alkali molybdo-vanadates of fixed concentration and at a definite temperature contain definite compounds which are in equilibrium with isomorphous mixtures of polyvanadates and poly molybdates. The yellow powders poor in vanadium are presumed to be definite compounds because they resist fractionation, while the red crystals consist of isomorphous mixtures.

Comparison with other heteropoly-acids strongly suggests that the molybdo-vanadates do not contain either vanadium or molybdenum as the central atom of the complex anion. They are therefore written as derivatives of the hypothetical hexa-aquo-acid, H10[H2O6], in which the oxygen atoms in the anion have undergone complete or partial replacement by (V2O6)' radicals and by (Mo2O7)' or (MoO4)' radicals. The following examples are typical of series of alkali (and in some cases barium) salts that have been prepared:

3(NH4)2O.2V2O5.4MoO3.xH2O or ; 5(NH4)2O.2V2O5.12MoO3.xH2O or ; 2(NH4)2O.V2O5.6MoO3.xH2O or ; 3(NH4)2O.V2O5.6MoO3.xH2O or .

The following are also known, as well as many others for which coordinative formulae cannot be written:

4(NH4)2O.3V2O5.5MoO3.10H2O or ; 4K2O.3V2O5.4MoO3.7H2O or .

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