A NEW SILVER MOLYBDENUM(V) PHOSPHATE - XI-AG(MOO)2P2O7PO4

A new Mo(V) phosphate, Ag(MOO)2P2O7PO4, has been obtained as single cr ystals. It crystallizes in the space group P2(1)/c, a = 6.376(2) angst rom, b = 22.173(2) angstrom, c =8.718(2) angstrom, beta = 126.1(2)-deg rees. This compound isotypic with the sodium phase xiNa(MOO)2P2O7PO4, can be described as the stacking along b(over arrow pointing right) of [MoPO7]. layers involving MoO6 octahedra and monophosphate groups, wi th [Mo2P4O18]infinity double chains involving MoO6 octahedra and dipho sphate groups. The geometry of the polyhedra is similar to that usuall y observed in Mo(V) phosphates. This is the second silver Mo(V) phosph ate obtained to date. Its stability with respect to other Mo(V) phosph ates of univalent cations is discussed in terms of redox mechanisms.