Synthesis of mixed oxide composition

A process for producing a solid amorphous precursor gel composed of at least two metal oxides, said solid gel being free of water and hydroxyl groups and having a specific surface area higher than 10 square meters per gram, consisting essentially of reacting under reflux conditions in a substantially moisture-free atmosphere a mixture of metal alkoxide and metal halide at a temperature ranging from about room temperature up to about 250.degree. C. at a pressure ranging from atmospheric pressure to superatmospheric pressure ranging up to about 10 atmospheres forming a polymeric reaction product, said metal alkoxide being M.sup.n (OR).sub.n where M.sup.n is metal ion, R is an alkyl radical, and n is the valence of M.sup.n, said metal halide being M.sup.e X.sub.e where M.sup.e is metal ion different from M.sup.n, X is a halide selected from the group consisting of chloride, bromide, iodide and fluoride, and e is the valence of M.sup.e, heating said polymeric reaction product in a substantially moisture-free atmosphere at a temperature ranging from about 100.degree. C. up to about 300.degree. C. producing a polymeric product insoluble in ethyl ether at room temperature, pyrolyzing said ether-insoluble polymeric product in air or oxygen at a temperature ranging from about 450.degree. C. to about 600.degree. C. producing said gel comprised of a submicroscopically homogeneous mixture of the oxides of M.sup.n and M.sup.e and up to about 0.02% by weight of elemental carbon based on the total weight of said gel.