Crystal structure and chemistry of a complex indium phosphate framework material, (ethylenediammonium)In3P3O12(OH)2

The chemistry and structure of a novel indium phosphate material (RIPS-4), (H3NCH2CH2NH3)In3-P3O12(OH)2, are described. RIPS-4 was synthesized using ethylene diamine as a structure-directing organic agent. The X-ray crystal structure was determined from a 12×12×42 μm3 crystal in space group C2/m with a=18.662(4) Å, b=6.600(2) Å, c=12.573(3) Å and β=120.92(1)°. The structure consists of a complex edge- and vertex-shared open framework of InO6 octahedra and PO4 tetrahedra enclosing cavities occupied by ethylenediamonium ions. One set of octahedra share opposing edges to form chains along the b-axis matching the structural unit in rutile (TiO2). This rutile edge-shared chain has its projecting oxygen atoms shared with the vertexes of either a PO4 tetrahedron or a second type of InO6 octahedron. The O atoms are 2-connected, each to one In and one P, except for two protonated O atoms (hydroxyl groups) that connect to two and three In atoms, giving three- and four-coordinate O atoms, respectively.