Crystal structure of LaCuOS1-xSex oxychalcogenides

Solid solutions of LaCuOS1-xSex oxychalcogenides were prepared by solid-state reaction. The crystal structure of the solid solutions was refined by the Rietveld analysis. The Rietveld analysis revealed that S or Se ions dissolve completely in the system of LaCuOS-LaCuOSe. The crystal structure remains almost unchanged among the solid solutions except for a slight variation in the lattice constants. A difference in ionic radius between S and Se ions is responsible for the variation in the lattice constants. Long interatomic distances between La and S/Se estimated from the refined structure supported that the crystal structure of LaCuOS1-xSex can be visualized as a layered structure composed of La-0 and Cu-S/Cu-Se layers. (C) 2002 Elsevier Science B.V. All rights reserved.