Novel layered and network metal oxides: synthesis and characterization.

Abstract

The present investigation shows that reaction of electropositive metal iodides with the transition-metal oxides containing reducible cations affords a novel route for the synthesis of oxide bronzes as well as lower valence metal oxides. The investigation shows that I? is able to reduce W??, Mo?? and V?? in the solid state. From the standard reduction potential data in aqueous solutions (24), one would expect only V?? to be reduced by I?. Indeed, reduction of V?? by I? forms the basis of intercalation of mono- and divalent cations into VOPO?·2H?O (25) and of lithium into V?O? (26). The fact that WO? and MoO? are also reduced by I? reveals that oxidation-reduction behaviour of metal ions is different in the solid state at elevated temperatures as compared to the behaviour in aqueous solutions.