A MIXED-VALENT MOLYBDENUM MONOPHOSPHATE WITH AN ORIGINAL CAGE STRUCTURE CSMO6O10(MO2O7)(PO4)(4)

A new mixed valent molybdenum monophosphate, CsMo6O10(Mo2O7) (PO4)(4), has been synthesized. It crystallizes in the space group I (4) over b ar 2d with a 9.953(2) Angstrom, c = 26.413(4) Angstrom. Its original t hree-dimensional framework [Mo8P4O33](infinity) consists of corner-sha ring tetraoctahedral units Mo4O20 with the perovskite configuration, d itetrahedral groups Mo2O7, MoO6 octahedra, and single PO4 tetrahedra. This 3D lattice forms large cages where the Cs+ ions are located. An i mportant feature of this structure deals also with the fact that the ' 'molybdenum-oxygen'' framework is itself three-dimensional. The distri bution of the electrons in this structure is discussed on the basis of bond valence calculations and magnetic measurements. (C) 1997 Academi c Press.