Transition metal tetramolybdate dihydrates MMo4O13 center dot 2H(2)O(M = Co,Ni) having a novel pillared layer structure

Hydrothermal synthesis in the M/Mo/O (M = Co,Ni) system was investigated. Novel transition metal tetramolybdate dihydrates MMo4O13 center dot 2H(2)O (M = Co,Ni), having an interesting pillared layer structure, were found. The molybdates crystallize in the triclinic system with space group P-1,Z = 1 with unit cell parameters of a=5.525(3)angstrom, b=7.058(4)angstrom, c=7.551(5)angstrom, alpha=90.019(10)degrees, beta=105.230(10)degrees, gamma = 90.286(10)degrees for CoMo4O13 center dot 2H(2)O, and a=5.508(2)angstrom, b=7.017(3)angstrom, c=7.533(3)angstrom, alpha = 90.152(6)degrees beta = 105.216(6)degrees, gamma = 90.161(6)degrees for NiMo4O13 center dot 2H(2)O The structure is composed of two-dimensional molybdenum-oxide (2D Mo-O) sheets pillared With CoO6 octahedra. The 2D Mo-O sheet is made up of infinite straight ribbons built up by corner-sharing of four molybdenum octahedra (two MoO6 and two MoO5OH2) sharing edges. These infinite ribbons are similar to the straight ones in triclinic-K2Mo4O13 having 1D chain structure, but are linked one after another by corner-sharing to form a 2D sheet structure, like the twisted ribbons in BaMo4O13 center dot 2H(2)O (or in orthorhombic-K2Mo4O13) are. (C) 2008 Elsevier Inc. All rights reserved.