Synthetic pathways for new tubular transition metal hydroxo- and fluoro-selenites: Crystal structures of M(12)(X)(2)(SeO3)(8)(OH)(6) (M=Co2+, Ni2+; X=OH-)

The dumortierite-family structures M(12)X(2)(SeO3)(8)(OH)(6) (M = Co2+ and Ni2+; X = OH- and F-) have been synthesized. The crystal structures of the hydroxo-derivatives have been refined from X-ray powder diffraction data in the space group P6(3)mc (Z = 1) with a = 12.887(3) Angstrom and c = 4.981(4) Angstrom (M = Co2+, X = OH- or F-) and a 12.704(5) Angstrom and c = 4.925(6) Angstrom (M = Ni2+, X = OH- or F-). Application of the Partial Charge Transference Model allows the understanding of the selenite derivatives crystal chemistry. (C) 1996 Academic Press, Inc.