Chromium Azide, Cr(N₃)₃

Chromium Azide, Cr(N₃)₃, is obtained as a dark green amorphous mass by prolonged treatment of a solution of crystallised chromium nitrate in absolute alcohol with anhydrous sodium sulphate, and evaporation of the filtered liquid with the requisite quantity of sodium azide in a vacuum. The azide is very hygroscopic, and if its alcoholic solution is not thoroughly dry, partial hydrolysis occurs, basic azides of composition Cr(OH)(N₃)₂ and Cr(OH)₂N₃ being formed. A double compound with sodium, Cr(N₃)₃.3NaN₃, has been obtained in the form of green crystals.