Incommensurate structure of a lillianite-type samarium chromium sulfide Sm{sub 2/3}Cr{sub 2}S{sub 4}
- UMR-CNRS, Nantes (France)
- LMPM, Montpellier (France)
The structure of Sm{sub 2/3}Cr{sub 2}S{sub 4} has been solved from single-crystal X-ray diffraction data. This compound presents a 3 X a superstructure along a and an incommensurate superstructure along b close to 3 x b. The basic structure is described in the space group Pmnb with a = 3.5030(3) {Angstrom}, b = 10.9199(8) {Angstrom}, c = 12.7987(8) {Angstrom}, Z = 4, R = 0.046 for 916 observed reflections. The modulated structure refinement, taking into account the two superstructures, was carried out in a (3 + 2)D superspace group and leads to R = 0.063 for 1706 reflections. This structure consists of staggered double columns of [CrS{sub 6}] octahedra connected by samarium atoms in a trigonal prismatic bicapped environment. This structure is reminiscent of that found in the lillianite mineral family. The statistical occupancy of samarium atoms (1/3), in agreement with the charge equilibrium (Sm{sup 3+}, Cr{sup 3+}, S{sup 2-}), is related to the superstructure.
- OSTI ID:
- 508636
- Journal Information:
- Journal of Solid State Chemistry, Vol. 127, Issue 2; Other Information: PBD: Dec 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Determination of the commensurately modulated structure of NbGe[sub 2/5]Te[sub 2] from twinned-crystal data
Synthesis and crystal structure of MCu(edta){center_dot}4H{sub 2}O: Molecular precursors for MCuO{sub 2} (M = Ca, Sr, Ba)