Crystal structures of CsFe 2S 3 and RbFe 2S 3: synthetic analogs of rasvumite KFe 2S 3

The isostructural alkali thioferrate compounds CsFe 2S 3, RbFe 2S 3 and KFe 2S 3 have been synthesized by reacting Fe and S with their corresponding AFeS 2 ( A=K, Rb, Cs) precursors. The crystal structures of these and binary compounds of intermediate composition were determined by Rietveld analysis...

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Bibliographic Details
Published inJournal of solid state chemistry Vol. 177; no. 6; pp. 1867 - 1872
Main Authors Mitchell, Roger H., Ross, Kirk C., Potter, Eric G.
Format Journal Article
LanguageEnglish
Published Elsevier Inc 2004
Subjects
Alkali thioferrate
Crystal structure
Rasvumite
Rietveld refinement
Rietveld refinement
Rasvumite
Alkali thioferrate
Crystal structure
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Summary:The isostructural alkali thioferrate compounds CsFe 2S 3, RbFe 2S 3 and KFe 2S 3 have been synthesized by reacting Fe and S with their corresponding AFeS 2 ( A=K, Rb, Cs) precursors. The crystal structures of these and binary compounds of intermediate composition were determined by Rietveld analysis of laboratory powder X-ray diffraction patterns. All of the synthesized compounds adopt the space group Cmcm (#63), Z=4 with: a=9.5193(8) Å, b=11.5826(10) Å, c=5.4820(4) Å for CsFe 2S 3; a=9.2202(7) Å, b=11.2429(9) Å, c=5.4450(3) Å for RbFe 2S 3; and a=9.0415(13) Å, b=11.0298(17) Å, c=5.4177(6) Å for KFe 2S 3. These mixed valence alkali thioferrates show regular changes in cell dimensions, AS 10 ( A=K, Rb, Cs) polyhedron volumes, polyhedron distortion parameters, and calculated oxidation state of Fe with respect to increasing size of the alkali element cation. The calculated empirical oxidation state of iron varies from +2.618 (CsFe 2S 3), through +2.666 (RbFe 2S 3) to +2.77 (KFe 2S 3).
ISSN:0022-4596
1095-726X
DOI:10.1016/j.jssc.2004.01.007