STRUCTURE OF MG6SO2(OH)(14) DETERMINED BY MICRO SINGLE-CRYSTAL X-RAY-DIFFRACTION

The structure of hexamagnesium sulfonyl tetradecahydroxide, Mg6SO2(OH) (14), has been determined with an extremely small single crystal (ca 0 .5 x 100 x 2.5 mu m) using synchrotron radiation [1.00(1) Angstrom]. T he crystal is orthorhombic with space group Ccmm (no. 63), a = 15.895( 1), b = 3.105(1), c = 13.367(1) Angstrom, V = 659.63(3) Angstrom(3) an d Z = 2. The final R and wR values are 0.073 and 0.083 for 105 crystal lographically independent reflections. The structure consists of MO(6) octahedra 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 MgO6 octahedra at the turning of the sheet and is statistically located with a probability of 0.5. Fine streaks obse rved perpendicular to the b axis on diffraction photographs indicate that the SO4 tetrahedra are distributed at random along the a and c ax es, but alternately along the b axis. All the H atoms are considered t o exist in the form of OH groups.