Vanadyl sulfate
chemical compound
Vanadyl(IV) sulfate describes a collection of inorganic compounds of vanadium with the formula, VOSO4(H2O)x where 0 ≤ x ≤ 6. The pentahydrate is common. This hygroscopic blue salt 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, one commercial source of vanadium.
Synthesis, structure, and reactions
Vanadyl sulfate is most commonly obtained by reduction of vanadium pentoxide with sulfur dioxide:
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 trihydrate has also been examined by crystallography. A hexahydrate exists below 13.6 °C (286.8 K). Two polymorphs of anhydrous VOSO4 are known.
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