Preparation and crystal structure of pentasodium bismuth bis-diphosphate Na5Bi(P2O7)2

The pentasodium bismuth bis-diphosphate has been synthesized and characterized by single-crystal X-ray diffraction. Na5Bi(P2O7)(2) is triclinic (P-1) with a = 9.276(3)Angstrom, b = 9.806(3)Angstrom, c = 7.272(1)Angstrom, alpha = 77.73(2), beta = 109.21(3), gamma = 97.92(2). V = 608.71(4)Angstrom(3), Z = 2. Crystal structure has been refined with a final R(F-2) = 0.0167 and R-w(F-2) = 0.0419 for 2672 reflections with F-2 > 4 sigma(F-2). The structure is built up from BiO7 polyhedra and P2O7 groups sharing corners and edges to form a two-dimensional framework having large windows stacked along the c direction to form tunnels. The Na+ cations are located in the interlayer space. (C) 1999 Academic Press.