CHEMISTRY OF ALKOXIDE PRECURSORS

In view of the increasing applications of metal alkoxides as precursors for ceramics, the physicochemical aspects of successive steps in the S-S-G process are being intensively investigated by sophisticated techniques like NMR (1H as well as multinuclear), SAXS, SANS, XANES, EXAFS and CRAMPS. Besides lower temperatures of sintering, the main advantage of the S-S-G process is the intimacy of mixing at the molecular level, resulting in the homogeneity of the final desired product. The formation of new bonds in mixtures of alkoxides has been confirmed by the isolation of polymetallic alkoxides, in which variations in the coordination environment of the central metal atom offer attractive possibilities for differing networks in ceramics with the same composition. The physicochemical properties of alkoxides have been explained on the basis of inductive and steric effects, degree of association, volatility as well as alcoholysis and hydrolysis reactions. These have been finally correlated with structural elucidation, which is being pursued much more vigorously during the past 1-2 years. © 1990.