Vanadium Suboxide, V₂O

The existence of this oxide is extremely doubtful. It is said to be the brown substance first formed when vanadium is gently heated in the air. Hittorf states that it is formed when vanadium pentoxide, V₂O₅, is reduced with aluminium by the Goldschmidt process, but other investigators have found that the product so obtained is a mixture of vanadium and hypovanadous oxide, VO.