NEUTRON-DIFFRACTION STUDIES ON MG(IO3)(2) CENTER-DOT-4H2O SINGLE-CRYSTALS

The crystal structure of Mg(IO3)(2).4H(2)O has been determined by neut ron single crystal diffraction (P2(1)/c, Z = 2, R = 2,2% on the basis of 1107 observed reflections). Mg(IO3)(2).4H(2)O forms a layered struc ture built up of octahedral Mg(H2O)4(IO3)2 units linked by hydrogen bo nds. The two crystallographically different water molecules are involv ed in asymmetric, nearly linear hydrogen bonds to adjacent iodate ions (nu(OD) of matrix isolated HDO: 2480, 2475, 2425 und 2412 cm(-1), LR spectroscopic data, 90 K). The strength of the hydrogen bonds as well as that of other iodate hydrates is discussed in terms of both the syn ergetic effect and Brown's bond valences.