Abstract: Chlorine or bromine-containing polysilanes of the general formula (R.sub.2 Si)(RSi)(R'Si) are disclosed. In these polysilanes there are also bonded to the silicon atoms other silicon atoms and chlorine or bromine atoms, R is an alkyl radical containing 1 to 4 carbon atoms, and R' is selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula A.sub.y X.sub.(3-y) Si(CH.sub.2).sub.z -- wherein each A is independently selected from a hydrogen atom or alkyl radicals containing 1 to 4 carbon atoms, y is an integer equal to 0 to 3, X is chlorine or bromine, and z is an integer greater than or equal to 1. These preceramic polymers can be pyrolyzed at elevated temperatures under an inert atmosphere to yield ceramic materials or articles. These polysilanes may also be converted into other preceramic polymers which can be pyrolyzed to ceramic materials or articles.