|Molar mass||163.00 g/mol|
|Appearance||Blue crystalline solid|
|Melting point||105 °C decomp.|
|Solubility in water||Soluble|
|EU Index||Not listed|
|Other anions||Vanadyl chloride
|Other cations||Vanadium(III) sulfate|
|Related compounds||Vanadyl acetylacetonate|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Vanadyl(IV) sulfate, VOSO4, is a well known inorganic compound of vanadium. This very hygroscopic blue solid is one of the most common sources of vanadium in the laboratory, reflecting its high stability. It features the vanadyl ion, VO2+, which has been called the "most stable diatomic ion." Vanadyl sulfate is an intermediate in the extraction of vanadium from petroleum residues, a major commercial source of vanadium. Vanadyl sulfate is a component of some food supplements and drugs. Vanadyl compounds mimic the effects of insulin and is regarded as an essential trace element.
Synthesis, structure, and reactions
- V2O5 + 7 H2O + SO2 + H2SO4 → 2 [V(O)(H2O)4]SO4
From aqueous solution, the salt crystallizes as the pentahydrate, the fifth water is not bound to the metal in the solid. Viewed as a coordination complex, the ion is octahedral, with oxo, four equatorial water ligands, and a monodentate sulfate. The V=O bond distance is 160 pm in length, about 50 pm shorter than the V–OH2 bonds. In solution, the sulfate ion dissociates rapidly.
- [V(O)(H2O)4]SO4 + 2C5H8O2 + Na2CO3 → [V(O)(C5H7O2)2] + Na2SO4 + 5 H2O + CO2
In acidic solution, oxidation of vanadyl sulfate gives yellow-coloured vanadyl(V) derivatives. Reduction, e.g. by zinc, gives vanadium(III) and vanadium(II) derivatives, which are characteristically green and violet, respectively.
Occurrence in nature
Like most water-soluble sulfates, vanadyl sulfate is only rarely found in nature. Anhydrous form is pauflerite, a mineral of fumarolic origin. Hydrated forms, also rare, include hexahydrate (stanleyite), pentahydrates (minasragrite, orthominasragrite, and anorthominasragrite) and trihydrate - bobjonesite.
- Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. p. 1157. ISBN 0-08-022057-6.
- Günter Bauer, Volker Güther, Hans Hess, Andreas Otto, Oskar Roidl, Heinz Roller, Siegfried Sattelberger in "Vanadium and Vanadium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.
- Bryant, Burl E.; Fernelius, W. Conard (1957), "Vanadium(IV) Oxy(acetylacetonate)", Inorg. Synth. 5: 113–16, doi:10.1002/9780470132364.ch30