Abstract: Carborane-silane/siloxane compounds having unsaturated organic end groups e represented by the formula: ##STR1## wherein: u and x are independently selected positive integers, v and w are independently selected integers greater than or equal to zero, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are independently selected from the group consisting of alkyl, aryl, alkylaryl, haloalkyl, haloaryl and mixtures thereof; A and E are independently selected from the group consisting of O, an aliphatic bridge, an aryl bridge and mixtures thereof; and R.sup.9 and R.sup.10 are unsubstituted or substituted vinyl or ethynyl groups.

Abstract: Thermally stable thermosets are formed from novel linear polymer containing acetylenic units and a random distribution of organotransition metal complexes, siloxane, boron, and/or carborane-siloxane units formed by crosslinking of the linear copolymers through the acetylene units in the polymer backbone. The thermosets can be used as structural components in high temperature and oxidizing environments or as pyrolytic precursors to metal containing ceramics, ceramic films and fibers having enhanced strength and toughness with superior mechanical, optical, electrical and/or magnetic properties.