Preparation and structural properties of new series of mixed-anion compounds: rare earth fluorosulfides

Rare earth fluorosulfides with the following compositions: LnSF and Ln(2)AF (4)S(2) have been prepared by solid state routes. These structures can be d escribed as a stacking of fluoride-based slabs ([Ln(2)F(2)](4+) in LnSF and [Ln(2)AF(4)](4+) in Ln(2)AF(4)S(2)) and double layers [S-2](4-). The fluor ide blocks are related to fluorite-type structure. The relative compactness of the fluoride blocks leads to a relaxation of the Ln-S bond lengths. (C) 2001 Elsevier Science B.V. All rights reserved.