title: Vanadium(III) oxide
text: # Vanadium(III) oxide
  
  Vanadium(III) oxide is the inorganic compound with the formula $V_2O_3.$ It is a black solid prepared by reduction of $V_2O_5$ with hydrogen or carbon monoxide. It is a basic oxide dissolving in acids to give solutions of vanadium (III) complexes. $V_2O_3$ 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. This also distorts the crystal structure to a monoclinic space group: C2/c.
  
  Upon exposure to air it gradually converts into indigo-blue $V_2O_4.$
  
  In nature it occurs as the rare mineral karelianite.
  
  