Inorganic polymers. Part I. A solid inorganic foam

The preparation of a solid inorganic foam is reported. Hexaaminocyclotriphosphazatriene, N3P3(NH2)6, used either without purification, or when recrystallized from water, gives phospham as a dense powder. If, however, the starting material is precipitated from its aqueous solution by suitable organic solvents, a foamed material results. Possible reasons for this divergence in behavior are discussed. The ammonia evolved on thermal decomposition acts as a built‐in foaming agent.