AN ALUMINOPHOSPHATE OF MOLYBDENUM (V) WITH A TUNNEL STRUCTURE - CS9MO9AL3P11O59

A new Mo(V) aluminophosphate, Cs9Mo9Al3P11O59, has been isolated. This hexagonal phase (P6(3)/m; a = 16.989(3) Angstrom, c = 11.866(3) Angst rom) exhibits a tunnel-type structure with a host lattice that is comp osed of MoO6 octahedra and AlO4 and PO4 tetrahedra. In fact, this open framework can be described in terms of tetrahedral Al3P10O40 units an d octahedral Mo3O15 units. The latter consist of two edge-sharing octa hedra sharing one of their common apices with one MoO6 octahedron. Suc h units form [AlMo3P3O22](infinity), columns running along c. The asse mblage of these columns through the apices of their polyhedra but also through single monophosphate groups leads to the [Mo9Al3P11O59](infin ity) host lattice with tunnels running along c where the cesium cation s are located. The relationships between this structure and those of c arnegeite and Cs6Mo7O9(PO4)(7) . H2O are discussed. (C) 1995 Academic Press, Inc.