Vanadium(III) oxide is the inorganic compound with the formula V₂O₃. It is a black solid prepared by reduction of V₂O₅ with hydrogen or carbon monoxide. It is a basic oxide dissolving in acids to give solutions of vanadium(III) complexes. V₂O₃ has the corundum structure. It is antiferromagnetic with a critical temperature of 160 K. At this temperature there is an abrupt change in conductivity from metallic to insulating.