A Rietveld refinement of NaCl-type Ca{sub 5}Y{sub 4}S{sub 11}

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/0022-4596(95)80007-C· OSTI ID:237552

Thompson, J G; Withers, R L ^[1]; Otero-Diaz, L C ^[2]

---

1. Australian National Univ., Canberra (Australia)
2. Universidad Complutense, Madrid (Spain)

The crystal structure of Ca{sub 5}Y{sub 4}S{sub 11} [a = 6.942(1) {angstrom}, {alpha} = 33.380(5){degrees}, space group R3m, No. 166, Z = (2/11), D{sub x} = 3.042 g cm{sup -3}] was determined using Rietveld refinement of X-ray powder diffraction data collected with CuK{alpha}{sub 1} radiation using a Guiner-Haegg camera. Ca{sub 5}Y{sub 4}S{sub 11} is one end-member composition (x=2/7) of the solid-solution (1-x)CaS.xY{sub 2}S{sub 3}, which can be considered as a modulated NaCl-type structure with modulation wavevector q = {1/2}(111){sup *}. The sulfur sublattice is fully occupied but the metal sublattice contains (2/11) vacancies on average. The refinement showed that the additional observed satellite reflections were almost entirely due to metal atom/vacancy ordering rather than sulfur atom displacement. Large anisotropic thermal parameters on both the sulfur and metal atoms were consistent with disordered displacement of these atoms by 0.2-0.4 {angstrom} normal to [111]. The chemical plausibility of the refined structure and the implication of this result for other substoichiometric NaCl-type solid solutions are discussed.

• OSTI ID: 237552
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 119; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM SULFIDES
CRYSTAL STRUCTURE
STOICHIOMETRY
YTTRIUM SULFIDES