Synthesis and structure of Na-2[(HO3PCH2)(3)NH]1.5H(2)O: The first alkaline triphosphonate

Sodium nitrilotris(methylenephosphonate), Na-2[(HO3PCH2)(3) NH]1.5H(2)O, ha s been synthesized as single crystals and as bulk polycrystalline single ph ase. This compound is triclinic, space group <P(1)over bar>, a = 7.398(1) A ngstrom, b = 8.446(1) Angstrom, c = 10.086(1) Angstrom, alpha = 81.39(1)deg rees, beta = 89.29(1)degrees, gamma = 81.18(1)degrees, Z = 2 and the struct ure was solved from single-crystal data. The crystal structure was used to refine the ponder diffraction data by the Rietveld method. The structure co ntains Na4O16 tetramers, with the sodiums cations in distorted oxygen octah edral environments, and molecular units of the acid triphosphonate with pro tonated nitrogen atom. The framework is three-dimensional with small channe ls where two types of water molecules are located, This material has also b een characterized by thermal analysis, including a thermodiffractometric st udy, and infrared spectroscopy. (C) 2000 Academic Press.