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

Hypovanadous Sulphate, VSO4,7H2O

Hypovanadous Sulphate, VSO4.7H2O, is obtained in solution when vanadium pentoxide is dissolved in sulphuric acid and reduced in the absence of air with sodium-amalgam, zinc, or cadmium. The separation of the hydrate is effected by first reducing the pentoxide in acid solution with sulphur dioxide to the blue tetravalent state, and then continuing the reduction electrolytically in an atmosphere of carbon dioxide until the colour of the solution changes to violet. Concentration in vacuo deposits transparent, reddish-violet crystals, which become bluish-violet even with traces of oxygen. The crystals are monoclinic, and isomorphous with crystals of ferrous sulphate, FeSO4.7H2O. They undergo oxidation rapidly on exposure to air and are readily soluble in water; dilute aqueous solutions in the absence of oxygen evolve hydrogen, while concentrated solutions also yield hydrogen sulphide. When brought into contact with other compounds the sulphate exerts the same reducing action as hypovanadous chloride. Its solutions have the property common to solutions of ferrous sulphate and chromous sulphate of absorbing nitric oxide.

Hypovanadous sulphate gives rise to double sulphates with the sulphates of ammonium, potassium, and rubidium. Hypovanadous ammonium sulphate, VSO4. (NH4)2SO4.6H2O, is formed when ammonium vanadate is electrolytically reduced in the presence of sulphuric acid. Hypovanadous potassium sulphate, VSO4.K2SO4.6H2O, is made by electrolytically reducing vanadium pentoxide in sulphuric acid solution, then adding potassium sulphate and continuing the reduction. In the same way hypovanadous rubidium sulphate has been prepared, but it has not been found possible to obtain it free from vanadium rubidium alum. These double sulphates form violet, monoclinic crystals, which are not stable in air; they are not so rapidly oxidised as the simple hypovanadous salt, however; they are less soluble in water than the simple salt, and give yellow or brownish-yellow solutions which may contain complex ions. Hypovanadous sulphate also has the property of forming mixed crystals with magnesium, ferrous and chromous sulphates; these have the formulae: (V.Mg)SO4.7H2O; (V.Fe)SO4.7H2O; (V.Cr)SO4.7H2O.

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