Silicon Nitrimide, Si₂N₃H

Although silicon di-imide can be heated gently in an inert atmosphere without decomposition, it loses ammonia when heated in nitrogen to 900° C., yielding the nitrimide, a substance of unknown constitution, thus:

2Si(NH)₂ = Si₂N₃H + NH₃.

The product is an amorphous powder, stable towards water. When it is heated to 1200°-1300° C. it loses the hydrogen remaining in it as ammonia, and leaves a residue of nitride, thus:

3Si₂N₃H = 2Si₃N₄ + NH₃.

Making certain assumptions as to the constitution of the nitrimide and nitride, this change may be represented tentatively as follows, from Nitrimide to Nitride:

(N≡Si-NH-Si≡N)₃ → (N≡Si-N=Si=N-)₃ + 3H → (N≡Si-N=Si=N-)₂ + (N≡Si-)₂ + NH₃ → (N≡Si-N=Si=N-Si≡N)₂ + NH₃