Lithamide, LiNH₂

The Lithamide, or lithium amide can be prepared by the action of lithium on liquefied ammonia, or by passing dry ammonia over the metal at 400° C. It is a white, crystalline substance of density 1.178 at 17.5° C., and melts without decomposition at 373° to 375° C. It is more stable than the amides of sodium and potassium. On heating, it partially sublimes, but in vacuum at 620° to 640° C. it is transformed into lithium imide. It is converted by water into the hydroxide and ammonia.

Several investigators have described products formed by the interaction of lithium and liquefied ammonia, but there seems to be a considerable measure of uncertainty as to the true nature of the reaction.

The mechanism of the action of hydrogen on lithium nitride is also a matter of dispute, trilithium amide, Li₃NH₂, and trilithium ammonium, Li₃NH₄, being products mentioned in the literature. Lithium imide, Li₂NH, is a yellowish-white solid formed by the decomposition in sunlight of trilithium amide -

Li₃NH₂=Li₂NH+LiH.