Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-27T06:45:42.007Z Has data issue: false hasContentIssue false

The crystal chemistry of the solid solution series between chalcostibite (CuSbS2) and emplectite (CuBiS2)

Published online by Cambridge University Press:  05 July 2018

M. F. Razmara
Affiliation:
Department of Earth Sciences, University of Manchester, Manchester, M13 9PL, UK
C. M. B. Henderson
Affiliation:
Department of Earth Sciences, University of Manchester, Manchester, M13 9PL, UK
R. A. D. Pattrick
Affiliation:
Department of Earth Sciences, University of Manchester, Manchester, M13 9PL, UK
A. M. T. Bell*
Affiliation:
Department of Earth Sciences, University of Manchester, Manchester, M13 9PL, UK
J. M. Charnock
Affiliation:
Department of Earth Sciences, University of Manchester, Manchester, M13 9PL, UK
*
* Current address: Department of Chemistry, Lensfield Road, Cambridge CB2 1EP

Abstract

Sulphosalts in the system CuSbS2-CuBiS2 (chalcostibite-emplectite) form a complete solid solution series. Seven compositions with the general formula Cu(SbxBi1–x)S2 have been synthesized using dry methods at 310°C. All members of the series are orthorhombic (space group Pnma) and show smoothly increasing a and b cell parameters with substitution of Bi for Sb; the c cell parameter increases up to 50% CuBiS2 substitution and then becomes constant. DSC experiments on CuBiS2 show an endothermic heat effect (2.45 kJ/mol.) at 472°C due to the breakdown reaction to Cu3BiS3 (wittichenite) plus Bi2S3 (bismuthinite). With the addition of 10% CuSbS2 to CuBiS2, the decomposition temperature increases and the endothermic peak is broadened but the energy remains essentially the same (2.53 kJ/mol.). No evidence of this decomposition was observed when the amount of the CuSbS2 component was >30%. The local structure and co-ordination of Cu in the samples were studied by EXAFS analysis of the Cu-K edge but no significant variation occurs in the local Cu environment. The Debye-Waller factor for the first shell of S atoms surrounding Cu in end member CuSbS2 tends to be slightly smaller than for the intermediate solid solutions, suggesting that the tetrahedral Cu environments in the intermediate composition samples is somewhat more disordered than in the end-member. The low expansion characteristics along c appear to be controlled by the linkages between the (CuS3 + BiS2) sheets perpendicular to c being relatively inflexible.

Type
Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Binsted, N., Campbell, J.W., Gurman, S.J. and Stephenson, P.C. (1991) CCLRC Daresbury Laboratory EXCURV program.Google Scholar
Brown, G.E., Jr., Calas, G., Waychunas, G.A. and Petiau, J. (1988) X-ray absorption spectroscopy and its application in mineralogy and geochemistry. Reviews in Mineralogy (Min. Soc. Amer.), 18, 431512.Google Scholar
Chen, T.T. and Chang, L.L.Y. (1971) Phase relations in the systems Ag2S-Sb2S3-Bi2S3 and Cu2S-Sb2S3-Bi2S3 . Geol. Soc. Amer. Abstr. Program, 3(7), 524.Google Scholar
Cernik, R.J., Murray, P.K., Pattison, P. and Fitch, A.N. (1990) A two-circle powder diffractometer for synchrotron radiation with a closed loop encoder feedback system. J. Appl. Crystallogr., 23, 292-6.CrossRefGoogle Scholar
Collins, S.P., Cernik, R.J., Pattison, P., Bell, A.M.T. and Fitch, A.N. (1992) A two-circle powder diffractometer for synchrotron radiation on station 2.3 at the SRS. Rev. Sci. lnstrum., 63, 1013-4.CrossRefGoogle Scholar
Grigas, I., Mozgova, N.N., Orlyukas, A. and Samulenis, V. (1975) The phase transition in CuSbS2 crystals. Sov. Phys. Crystallogr., 20, 741-2.Google Scholar
Gurman, S.J., Binsted, N. and Ross, I. (1984) A rapid, exact, curved wave theory for EXAFS calculations. J. Phys. C: Solid State Phys., 17, 143-51.CrossRefGoogle Scholar
Hedin, L. and Lundqvist, S. (1969) Effects of electronelectron and electron-phonon interactions on the one-electron states of solids. Solid State Phys., 23, 1181.Google Scholar
Hofmann, W. (1933) Strukturelle und morphologische zusammenhaenge bei erzen vom formeltyp ABC2 I. Die struktur von wolfsbergit CuSbS2 and emplektit CuBiS2 und deren Beziehungen zu der struktur von Antimonit Sb2S3 . Z Kristallogr., 84, 177203.Google Scholar
Lee, P.A. and Pendry, J.B. (1975) Theory of the extended X-ray absorption fine structure. Physical Review, B11, 2795-811.CrossRefGoogle Scholar
Lind, I.L. and Makovicky, E. (1982) Phase relations in the system Cu-Bi-S at 200° 108 Pa by hydrothermal synthesis – microprobe analysis of tetrahedrites – a warning. Neues Jahrb. Mineral., Abh., 145, 134-56.Google Scholar
Murray, A.D., Cockcroft, J.K. and Fitch, A.N. (1990) Powder Diffraction Program Library (PDPL). Univ. College, University of London.Google Scholar
Portheine, J.C. and Nowacki, W. (1975) Refinement of the crystal structure of emplectite, CuBiS2. Z. Kristallogr., 141, 387402.CrossRefGoogle Scholar
Rietveld, H.M. (1969) A profile refinement method for nuclear and magnetic structures. J. Appl. Crystallogr., 2, 6571.CrossRefGoogle Scholar
Wang, N. (1989) Emplectite: Synthesis, powder data and thermal stability. Neues Jahrb. Mineral. Mh., 521-3.Google Scholar