HYDROTHERMAL SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF THE MOLYBDENUM(VI) ARSENATE (C5H5NH)2(MO2O5)-(HASO4)2-CENTER-DOT-H2O

A new molybdenum(VI) arsenate, (C5H5NH)2(Mo2O5)(HAsO4)2-H2O, has been synthesised hydrothermally at 230-degrees-C and characterized by singl e-crystal X-ray diffraction and thermogravimetric analysis. The compou nd crystallizes in the triclinic space group P1BAR with a = 7.708(1), b = 12.262(3), c = 12.281 (4) angstrom, alpha = 115.98(2), beta = 103. 36(2), gamma = 98.71 (2)degrees, Z = 2 and R = 0.0293. The structure i s composed of pyridinium cations, water molecules and [(Mo4O10) (HAsO4 )4]4- cluster anions. The anions, which lack Mo-Mo bonds, are linked b y strong hydrogen bonds to form layers parallel to the ac plane with p yridinium cations between the layers. Water molecules are within the l ayers and are linked to both the cluster anions and pyridinium cations through hydrogen bonding.