Silicon Di-imide, Si(NH)₂

Silicon Di-imide, Si(NH)₂, is formed from the tetramide by loss of ammonia:

Si(NH₂)₄ = Si(NH)₂ + 2NH₃,

which commences above 0° C. and is complete at 120° C. It is also produced by the action of liquid ammonia on silicon disulphide or thio-chloride, and may be isolated from the product of the action of gaseous ammonia on silicon tetrachloride.

Silicon di-imide is a white, infusible, amorphous powder, stable towards moderate heat in absence of air; it is basic, forming the white hydrochloride Si(NH)₂.2HCl. Water hydrolyses it to silicic acid and ammonia.