Addition of aqueous hydroxylamine hydrochloride in aqueous solution of ammonium (MO4)(n-) salts at a fixed pH, maintained by adding HCl drops, has yielded amorphous, reduced oxides of intermediate valence such as VO2, Cr2O3, Fe3O4, MoO2, and (NH4)(0.33) WO3. The as-prepared products crystallize on heating to 300-500 degrees C.