Structure of Mg_6SO_2(OH)_(14) Determined by Micro Single-Crystal X-ray Diffraction

摘要

The structure of hexamagnesium sulfonyl tetradecahy-droxide, Mg6SO2(OH)14, has been determined with an extremely small single crystal (ca 0.5 x 100 x 2.5 pm) using synchrotron radiation [1.00(1) A]. The crystal is orthorhombic with space group Ccmm (no. 63), a = 15.895(1), b = 3.105(1), c = 13.367(1) A, V = 659.64 (3) A3 and 2 = 2. The final R and wR values are 0.073 and 0.083 for 105 crystallographically independent reflections. The structure consists of MOf, octahe-dra and SO4 tetrahedra. The MgO6 octahedra share their edges to form zigzag sheets parallel to (100). The SO4 tetrahedron shares two of the O atoms with the MgOg octahedra at the turning of the sheet and is statistically located with a probability of 0.5. Fine streaks observed perpendicular to the b* axis on diffraction photographs indicate that the SO4 tetrahedra are distributed at random along the a and c axes, but alternately along the b axis. All the H atoms are considered to exist in the form of OH groups.