This invention relates to a generic process for producing a
refractory oxide which comprises reacting an aqueous
hydrogen fluoride solution or its derivatives with: at least one
metal fluoride reactant; or at least one
metal fluoride reactant and at least one
metal oxide reactant; or at least one metal
oxide reactant, to produce either a colloidal mixture or a solution;
drying either the colloidal mixture or solution; heating the dried product to produce a
solid state metal hydroxyfluoride; heating the hydroxyfluoride to a temperature at which it chemically decomposes into a cationically-homogeneous and nanostructured
solid state metal oxyfluoride; and performing one of the following heating steps: (i) to a
solid state
decomposition-temperature where the oxyfluoride chemically decomposes into a
refractory oxide; or, (ii) to a
molten state decomposition-temperature where the oxyfluoride chemically decomposes into a
refractory oxide; or, (iii) to a vapor state
decomposition-temperature where the oxyfluoride chemically decomposes into a refractory oxide.