A layered oxide containing vanadium together with phosphorus or arsenic and an organic group may be prepared which has a unique layered structure of the formula VORAO 3 ·nS or VOROAO 3 · nS where A is phosphorus or arsenic, S is a solvent molecule, R is an unsubstituted or alkyl-, alkoxy- or aryl-substituted alkyl or aryl group, and n is zero or a positive number. These layered compounds are characterized in that the vanadium is substantially in a 4 oxidation state and is present in an amount such that the molar ratio of A:V ranges from 0.8 to 1.2 throughout the oxide. Also the R groups are covalently bound to an A atom in the vanadium oxide layer directly through either carbon or oxygen atoms.