Composition of the crystallohydrates, and some of the properties of vanadyl fluoride

1. The vanadyl fluoride formed in the system HF-VO2-H2O crystallizes in the form of hydrates with the compositions VOF2·4H2O and VOF2·2H2O. At HF concentrations above 68.45%, an anhydrous vanadyl fluoride exists, which may thus be synthesized from VO2 and HF. 2. Quadrivalent vanadium in concentrated hydrofluoric acid solutions retains the vanadyl group vr2+, and does not add on an additional fluorine ion, which is substantially different from the behavior of the fluorides of silicon, titanium, zirconium, and hafnium, which form complex penta- and hexafluor acids under similar conditions.