Abstract: Silazanes and related compounds are prepared by (a) providing a precursor containing at least one Si--N bond, cleaving an Si--N bond in the precursor in the presence of hydrogen or a hydrogen donor, and reacting the cleavage product with a second cleavage product or with a compound containing an Si--H bond, an N--H bond, or both, to produce an initial silazane product having at least one newly formed Si--N bond or (b) providing one or more reactants which contain an Si--H bond and an N--H bond, and causing reaction to occur between the two bonds in the presence of a transition metal catalyst to form an initial silazane product having newly formed Si--N bonds. Further products may result from additional reaction of either type. Novel compounds, including siloxazanes and high molecular weight polysilazanes, are provided. The compounds may be pyrolyzed to yield ceramic materials such as silicon nitride, silicon carbide and silicon oxynitride.