PREPARATION AND CHARACTERIZATION OF BI-CONTAINING TERNARY CHALCOGENIDES WITH LAYERED COMPOSITE CRYSTAL-STRUCTURE

Bismuth-containing ternary chalcogenides with layered composite crystal structure expressed as (BiX)nTX2 or (BiX)n(TX2)2 where T = Ti, V, Nb, Ta and X = S, Se have been prepared and characterized using powder X-ray diffraction (XRD), electron diffraction and intercalation. The extreme prefer-red orientation characteristic of this kind of compound has been effectively depressed by treatment of the chalcogenides with an adhesive agent. The lattice constants of both subcells for the Bi-Ta group chalcogenides (BiS)1.09TaS2, (BiSe)1.09TaSe2 and (BiS)1.08(TaS2)2, have been obtained on the basis of the XRD pattern with depressed preferred orientation. It has been found that the interface of the two adjacent TX2 sandwiches in the (BiX)n(TX2)2-type chalcogenides has the character of a van der Waals gap, through the treatment of the chalcogenides with hydrazine monohydrate or aqueous CaCl2 solution.