A MOLYBDENUM(V) MONOPHOSPHATE WITH A LAYER STRUCTURE, BAMO4O8(PO4)2

A new Mo(V) monophosphate BaMo4O8(PO4)2, with a layer structure, has b een isolated. It crystallizes in the space group I42mBAR, with a = 7.4 75(1) angstrom and c = 11.156(l) angstrom. The close relationships bet ween the structure of this phase and that of the mixed-valent Mo(III)- Mo(IV) phosphate CS3(MOO)4(PO4)3 are remarkable. Both phosphates are c haracterized by Mo4O16 octahedral units built up from Mo4O46+ cubes, f orming identical [Mo4P2O16]infinity layers parallel to (001). The laye r structure of the present Mo(V) monophosphate derives from the inters ecting tunnel framework of the intermediate valent Mo monophosphate by just suppressing the PO4 tetrahedra along one direction and by transl ating two successive [Mo4P2O16]infinity layers by (a + b)/2. (C) 1994 Academic Press, Inc.