Hydrothermal synthesis of solid state materials and crystallography

Abstract

The structure solution of the new polyoxovanadate compound([V16O31(OH)7]Cl· 15H2O), has been done by the SHELX crystal solution software. The compound was synthesized solvothermally at 170 0C in the Northwestern University. The compound crystallizes in the space group C2/c of the monoclinic system with eight formula units in a cell of dimensions a = 18.070 (2) Å, b = 17.414 (2) Å, c = 15.1154 (18) Å, â= 97.696 (2)°, V= 4713.8 (10) Å3 (T = 153 K). The structure is composed of vanadium-oxygen clusters encapsulating Cl¯ anion. Each of the V centers has square pyramidal geometry coordinated by five O atoms. The 16 (VO5) units are fused together through common edges to form (V16O38) cage with Cl¯ anion in the middle. The single crystals of the [Ni(en)3(VO3)2] compound was synthesized by hydrothermal method. [Ni(en)3(VO3)2] compound is in the crystal system of hexagonal and in the space group P61. The unit cell parameters are a = 8.9940 (13) Å, b = 8.9940 (13) Å, c = 34.001 (7) Å and á = 90 0, â = 90 0, ã = 120 0. The structure is composed of VO4 tetrahedras which are joined with others by sharing corners into infinite chains running along the c axis. The complex cation [Ni(en)3]2+ are located between the chains The chain in the compound has a repetitive sequence of 12-nuclear corner-sharing tetrahedras. The compound was synthesized at 160 0C for 3 days in the steel reaction autoclaves which have PTFE (Polytetrafluoroethylene) cups in them.