A new zeolitic layered tungsten phosphate with high cationic mobility: Cs3W4O7(PO4)4⋠H2O

A mixed valent tungsten phosphate with an original layered structure Cs3W4O7(PO4)4⋅H2O has been synthesized, whose [W4P4O23]∞ layers consist of corner-shared PO4 tetrahedra, WO6 single octahedra and W2O11 bioctahedra. In this structure, H2O is zeolitic and Cs+ cations exhibit abnormally high thermal agitation along one direction at room temperature. Ionic conductivity measurements show that cesium exhibits a high mobility with two domains for the ionic conductivity versus temperature. Models are proposed based on 1D and 2D ionic conductions and taking also into consideration the possibility of electronic delocalization at higher temperature.