Vanadium Disilicide, VSi2, is prepared by reducing a mixture of vanadium trioxide and silicon with magnesium; vanadium pentoxide can also be employed with the addition of fluorspar to the mixture. Gin used a mixture of the pentoxide, silica, and coke. Vanadium disilicide is a very stable compound; it forms metallic prisms which melt at 1655° C., have a specific gravity of 4.42, and are hard enough to scratch glass. It is attacked by hydrofluoric acid, hydrogen chloride gas, and fused alkalis.
Hypovanadic oxide, VO2, and vanadium pentoxide, V2O5, both dissolve in hydrofluosilicic acid to yield a vanadyl fluosilicate and a vanadium fluosilicate, both of doubtful composition. |