HETEROMETAL ALKOXIDES AS PRECURSORS IN THE SOL-GEL PROCESS

The synthesis of bimetallic alkoxides has been followed by the prepara tion of intriguingly stable heterometal alkoxides containing three. or four different metal atoms in the same molecular species, which has l ed to the possibility of molecularly designing a single source precurs or suited to-the composition of the targeted final ceramic, This has b een made feasible by the extraordinary stability-of the framework of h eterometal alkoxides, which appears tb remain intact during the initia l hydrolysis reactions in the S-G process. The characterisation (by so phisticated physicochemical techniques including X-Ray crystal structu re elucidation in some cases) of heterometal alkoxides appears to have added a new dimension to heterometal coordination systems which appea r to be uniquely stable without the presence of metal-metal bonds or a uxiliary ligands like CO, etc., enerally required for stabilising poly metallic systems known so far.