PREPARATION OF A CHAIN-TYPE COMPOSITE CRYSTAL, BAXTIS3 (X=1.00-1.05)

Barium titanium sulfide, BaxTiS3 (x = 1.00-1.05), has been prepared by the reaction of CS2 with a mixture of BaCO3 and TiO2. The X-ray powde r diffraction and electron diffraction patterns show that the structur e is a chain-type composite crystal similar to SrxTiS3 and BaxFe2S4. T he structure consists of two interpenetrating cells, probably TiS3 and Ba cells, which have the parameter a in common, whereas the parameter c is different (c(1) and c(2) in a hexagonal setting). c(1) shrinks w ith increasing Ba content, while c(2) expands. The electron diffractio n spots and the Xray powder diffraction peaks cannot be indexed becaus e of an incommensurate structure; they were, therefore, indexed based on a four-dimensional formalism using the parameters a, c(1), and c(2) . In the expression of the four-dimensional formalism, this sulfide is represented by a single structure with a homogeneity range of X = 1.0 0-1.05. (C) 1994 Academic Press, Inc.