STRUCTURE OF NONASILVER SODIUM CYCLO-OCTAPHOSPHATE DINITRATE TETRAHYDRATE - AG9NAP8O24(NO3)2-BULLET-4H2O

Ag9NaP8O24(NO3)2.4H2O, M(r) = 1821.638, orthorhombic, Cmcm, a = 17.254 (5), b = 7.543 (1), c = 23.465 (5) angstrom, V = 3054 (2) angstrom3, Z = 4, D(x) = 3.961 Mg m-3, lambda(Ag K-alpha) = 0.5608 angstrom, mu = 3.086 mm-1, F(000) = 3392, T = 294K, final R = 0.044 for 1614 reflections. The title compound provides the first evidence for the coexistence of NO3 groups and condensed phosphoric anions in an atomic arrangement. The P8O24 ring anion has 2/m internal symmetry, while the NO3 group has mirror symmetry. Layers containing the phosphoric rings alternate with layers of NO3 groups perpendicular to the c direction, while all the water molecules are located in planes x = 0 and 1/2. A statistical Ag-Na distribution is observed for one of the cation positions. Two of the four water molecules are not involved in the associated cation polyhedra.