| Vanadium Dinitride, VN2, is obtained as a black powder by passing ammonia gas over vanadium oxytrichloride, VOCl3, heated in a glass tube (to expel the ammonium chloride formed), washing with ammonium hydroxide, and drying in vacuo over sulphuric acid. It undergoes oxidation and evolves ammonia on being exposed to air; on being heated it evolves nitrogen and forms the mononitride, VN; it is readily attacked by molten caustic potash and hot nitric acid. |