SYNTHESIS AND STRUCTURE OF NEW BISMUTH CONTAINING OXYCHLORIDES - BISR3O3CL3 AND BICA3O3CL3

A new bismuth strontium oxychloride BiSr3O3Cl3 has been synthesized and structurally characterized from single crystal X-ray diffraction data. The compound crystallizes in the orthorhombic space group Pnma (#62) with a=6.687(2) Å, b=11.4618(8) Å, c=11.565(2) Å, V=886,4(3) Å3, and Z=4. From the formula weight of 626.20, the density is calculated to be 4.693 g/cm3. The structure of BiSr3O3Cl3 can be described as a layered structure arranged in sequence Cl/Sr-O/Bi-Sr-O-Cl/Sr-O/Cl along the b axis. The Bi-Sr-O-Cl layer is unique among all the known bismuth oxyhalides in that oxygen and halide are mixed in one layer. Two types of Sr atom and one type of Bi atom are found. Strontium of the Sr-O layer is coordinated by three O atoms with Sr-O distances ranging from 2.404(7) to 2.557(6) Å and by five Cl atoms with Sr-Cl distances from 3.010(2) to 3.394(3) Å. Strontium of the Bi-Sr-O-Cl layer is coordinated to three oxygen atoms with Sr-O distances in the range of 2.419(8) to 2.505(6) Å and to six chlorine atoms with Sr-Cl distances in the range 2.922(3) to 3.796(4) Å. The Bi atom is coordinated by three O atoms and two Cl atoms with Bi-O bond lengths ranging from 2.062(8) to 2.071(6) Å and Bi-Cl bond lengths of 3.472(3) Å. The isostructural compound BiCa3O3Cl3 was also synthesized; the cell dimensions from single crystal data are a=6.383(3) Å, b=10.803(3) Å, and c=11.422(3) Å. © 1992 Academic Press, Inc.