Borasilazane Polymeric Precursors for Borosilicon Nitride

The reaction of H 3 B·S(CH 3 ) 2 with the (CH 3 SiHNH) n cyclic oligomers obtained by ammonolysis of methyldichlorosilane (CH 3 SiHCI 2 ) results in evolution of hydrogen and formation of cross‐linked products that contain borazine rings as well as boron atoms that are linked to three nitrogen atoms. Pyrolysis of the products in a stream of argon gives a high yield of a black “borosilicon carbonitride,” whereas pyrolysis in a stream of ammonia gives white “borosilicon nitride” in high yield.