Cobalt Nitride, Co₂N

Cobalt Nitride, Co₂N or Co₄N₂, has been prepared by heating cobalt in ammonia vapour to a little below 500° C., the most favourable temperature being 470° C. The metal slowly combines with the nitrogen, some 10.33 per cent, of the gas being absorbed.

Cobalt nitride is a dull grey powder, readily soluble in hydrochloric and sulphuric acids, yielding cobaltous salts, the nitrogen being liberated as ammonia. At 600° C. it evolves nitrogen, so that the formation of cobalt nitride can only proceed within very narrow limits of temperature. It is completely decomposed when heated in hydrogen or steam; in the latter case the reaction proceeds slowly.