| Hypovanadous Oxide, VO, was originally mistaken by Berzelius for the element. As in the case of uranium it is difficult to separate vanadium from the last remaining oxygen atom, and this oxide is found to enter as the vanadyl radical into a large number of compounds. Hypovanadous salts can be isolated in the pure state only with difficulty because of the readiness with which they undergo oxidation; they are among the most powerful inorganic reducing agents known, and frequently evolve hydrogen from aqueous or acid solution. They are best prepared by electrolytic reduction in an inert atmosphere of more highly oxidised compounds. They are isomorphous with magnesium salts and with the divalent salts of iron, chromium, and manganese. Double sulphates of the type VSO4.MgSO4.7H2O and VSO4.K2SO4.6H2O are known, as well as a complex cyanide, K4[V(CN)6].3H2O. |