Novel single-source volatile precursor compounds are disclosed, having the general formula(RO).sub.3 Si--O--Ti (OR).sub.3where each of the six R moieties in the C.sub.3 to C.sub.6 alkyl, preferably all being tert-butyl. The precursor compounds are suitable for use in dissociation methods, such as sol-gel and chemical vapor deposition, for preparing powders and films of stoichiometric SiO.sub.2.TiO.sub.2. Optical films to provide an anti-reflective surface on a lens, window or the like and powders for catalytic substrates, etc. are prepared using the SiO.sub.2.TiO.sub.2 yielded by the single-source volatile precursor compound.