Synthesis, crystal structure and Ga-71 MAS NMR spectroscopy of a novel gallium phosphatooxalate: [Ga-5(OH)(2)(C10H9N2)(C2O4)(PO4)(4)]center dot 2H(2)O

The synthesis and characterization of a novel three-dimensional gallium pho sphatooxalate is described; the structure consists of GaO4 tetrahedra and G aO6 octahedra linked by phosphate and oxalate groups to form two-dimensiona l sheets between which are GaO4N square pyramids, generating tunnels in whi ch the monoprotonated 4,4'-bipyridine molecules reside; Ga-71 MAS NMR confi rms the presence of four-, five- and six-coordinate Ga atoms.