Refinement of the Crystal Structure of Lead Polyphosphate Pb2(PO3)4

Lead polyphosphate Pb(2)(PO(3))(4) was prepared by hydrothermal synthesis. The structure was refined based on X-ray diffraction data: a = 7.306(3) angstrom, b = 7.990(3) angstrom, c = 17.385(7) angstrom, beta = 91.33(4)degrees, space group P2(1)/c, 3814 reflections, R(hkl) = 4.75, R(whkl)= 4.92, S = 1.030. The positional parameters and interatomic distances are compared with the corresponding values obtained previously for Pb(2)(PO(3))(4) and Sr(2)(PO(3))(4). The differences in the lengths of the P-O and Si-O bonds with the bridging and terminal 0 atoms in four-membered tetrahedral chains are analyzed. The difference in the P-O bond lengths is three times as large as that in the Si-O bond lengths, which reflects the electronic structures of the P and Si atoms and their electrostatic interactions with the oxygen anions.