Stabilization of a W(V) Diphosphate, W2O3·P2O7, with an Empty Tunnel Structure

Abstract A new form of WPO 5 has been synthesized which is to our knowledge the second pentavalent tungsten phosphate actually known. This phase is isotypic to CsP 8 W 8 O 40 and consequently can be described as a tungsten diphosphate, W 2 O 3 ·P 2 O 7 , with large empty eight-sided tunnels. Although it fundamentally differs from the first form, which is a monophosphate, WOPO 4 , the two structures are closely related by the existence of ReO 3 -type chains and slices, interconnected by P 2 O 7 or PO 4 groups, respectively. The stabilization of such an opened structure by adducts such as PbF 2 or KBr is discussed.