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 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".[1]
Vanadyl sulfate is an intermediate in the extraction of vanadium from petroleum residues, one commercial source of vanadium.[2]
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.[1][3] The trihydrate has also been examined by crystallography.[4] A hexahydrate exists below 13.6 °C (286.8 K).[5] Two polymorphs of anhydrous VOSO4 are known.[6]
The V=O bond distance is 160 pm, about 50 pm shorter than the V–OH2 bonds. In solution, the sulfate ion dissociates rapidly.
Being widely available, vanadyl sulfate is a common precursor to other vanadyl derivatives, such as vanadyl acetylacetonate:[7]
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,[8] a mineral of fumarolic origin. Hydrated forms, also rare, include hexahydrate (stanleyite), pentahydrates (minasragrite, orthominasragrite,[9] and anorthominasragrite) and trihydrate - bobjonesite.[10]
Medical research
Vanadyl sulfate is a component of food supplements and experimental drugs. Vanadyl sulfate exhibits insulin-like effects.[11]
Vanadyl sulfate has been extensively studied in the field of diabetes research as a potential means of increasing insulin sensitivity. No evidence indicates that oral vanadium supplementation improves glycaemic control.[12][13] Treatment with vanadium often results in gastrointestinal side-effects, primarily diarrhea.
Vanadyl sulfate is also marketed as a health supplement, often for bodybuilding. Deficiencies in vanadium result in reduced growth in rats.[14] Its effectiveness for bodybuilding has not been proven; some evidence suggests that athletes who take it are merely experiencing a placebo effect.[15]
^Tachez, M.; Theobald, F. R. (1980). "Liaisons hydrogène dans les cristaux de sulfate de vanadyle trihydrate VOSO4(H2O)3: Comparaison structurale de quatre sulfates de vanadyle hydrate". Acta Crystallographica B. 36 (12): 2873–2880. Bibcode:1980AcCrB..36.2873T. doi:10.1107/S056774088001045X.
^M. Tachez, F. Theobald, G. Trouillot. Crystal data for vanadyl sulphate hexahydrate VOSO4.6H2O. J. Appl. Crystallogr. (1976). 9, 246
^Krivovichev, S. V.; Vergasova, L. P.; Britvin, S. N.; Filatov, S. K.; Kahlenberg, V.; Ananiev, V. V. (1 August 2007). "Pauflerite, -VO(SO4), a New Mineral Species from the Tolbachik Volcano, Kamchatka Peninsula, Russia". The Canadian Mineralogist. 45 (4): 921–927. Bibcode:2007CaMin..45..921K. doi:10.2113/gscanmin.45.4.921.
^Hawthorne, F. C.; Schindler, M.; Grice, J. D.; Haynes, P. (1 October 2001). "Orthominasragrite, V4+O(SO4)(H2O)5, A New Mineral Species from Temple Mountain, Emery County, Utah, U.A.A.". The Canadian Mineralogist. 39 (5): 1325–1331. Bibcode:2001CaMin..39.1325H. doi:10.2113/gscanmin.39.5.1325.
^Schindler, M.; Hawthorne, F. C.; Huminicki, D. M.C.; Haynes, P.; Grice, J. D.; Evans, H. T. (1 February 2003). "Bobjonesite, V4+ O (So4) (H2O)3, A New Mineral Species from Temple Mountain, Emery County, Utah, U.s.a.". The Canadian Mineralogist. 41 (1): 83–90. Bibcode:2003CaMin..41...83S. doi:10.2113/gscanmin.41.1.83.
^Crans, D. C.; Trujillo, A. M.; Pharazyn, P. S.; Cohen, M. D. (2011). "How environment affects drug activity: Localization, compartmentalization and reactions of a vanadium insulin-enhancing compound, dipicolinatooxovanadium(V)". Coord. Chem. Rev. 255 (19–20): 2178–2192. doi:10.1016/j.ccr.2011.01.032.
^Talbott, Shawn M.; Hughes, Kerry (2007). "Vanadium". The Health Professional's Guide to Dietary Supplements. Lippincott Williams & Wilkins. pp. 419–422. ISBN978-0-7817-4672-4.
