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Cu and Zn ordering in aurichalcite

Published online by Cambridge University Press:  05 July 2018

J. M. Charnock
Affiliation:
Department of Earth Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
P. F. Schofield
Affiliation:
Department of Mineralogy, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
C. M. B. Henderson
Affiliation:
Department of Earth Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
G. Cressey
Affiliation:
Department of Mineralogy, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
B. A. Cressey
Affiliation:
Department of Geology, University of Southampton, Southampton Oceanography Centre, Southampton, SO14 3ZH, UK

Abstract

The advantages of X-ray absorption spectroscopy have been utilized to assess the Cu and Zn ordering in aurichalcite, (Cu5−xZnx)(OH)6(CO3)2. We have examined one hydrozincite sample and three aurichalcite samples in which the Cu:Zn ratios are in the range 1:3 to 2:3. Copper 2p XAS confirms that there is no monovalent copper in aurichalcite and that in each sample the copper might be distributed across more than one metal site. EXAFS, at the Cu and Zn K-edges, shows that the copper atoms preferentially enter the Jahn-Teller elongated, octahedral (M2) and trigonal bipyramidal (M4) sites, with the zinc atoms entering the more regular octahedral (M1) and tetrahedral (M3) site. Substantial solid solution towards the zinc rich region is facilitated by the substitution of copper by zinc on the M2 and M4 sites. This information, not easily obtained by X-ray diffraction, substantially enhances the understanding of the structure of aurichalcite.

Type
Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1996

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References

Binsted, N., Campbell, J.W., Gurman, S.J. and Stephenson, P.C. (1991) CCLRC Daresbury Laboratory EXCURV92 Program.Google Scholar
Braithwaite, R.S.W. and Ryback, G. (1963) Rosasite and aurichalcite and associated minerals from Heights of Abraham, Matlock Bath, Derbyshire, with a note on infrared spectra. Mineral Mag., 33, 441–9.Google Scholar
Couves, J.W., Thomas, J.M., Waller, D., Jones, R.H., Dent, A.J., Derbyshire, G.E. and Greaves, G.N. (1991) Tracing the conversion of aurichalcite to a copper catalyst by combined X-ray absorption and diffraction. Nature, 354, 465–8.CrossRefGoogle Scholar
Ghose, S. (1964) The crystal structure of hydrozincite, Zn5(0H)6(C03)2. Acta Cryst., 17, 1051–7.CrossRefGoogle Scholar
Gurman, S.J., Binsted, N. and Ross, I. (1984) A rapid, exact, curved wave theory for EXAFS calculations. Journal of Physics C: Solid State Physics, 20, 4005–12.Google Scholar
Harding, M.M., Kariuki, B.M., Cernik, R. and Cressey, G. (1994) The structure of aurichalcite, (Cu,Zn)5(OH)6(CO3)2, determined from a microcrystal. Ada Cryst. B50, 673–6.Google Scholar
Hedin, L. and Lundqvist, S. (1969) Effects of electron- electron and electron-phonon interactions on the one electron states of solids. Solid State Physics, 23, 1181 Google Scholar
Herman, R.G., Bogdan, C.E., Kumler, P.L. and Nuszkowski, D.M. (1993) Preparation and character Ization of hydrocarbonate precursors that yield successful alcohol synthesis catalysts. Materials Chemistry and Physics, 35, 233–9.CrossRefGoogle Scholar
Jambor, J.L. and Pouliot, G. (1965) X-ray crystallography of aurichalcite and hydrozincite. Canad. Mineral., 8, 385–9.Google Scholar
Lee, P.A. and Pendry, J.B. (1975) Theory of the extended X-ray absorption fine structure. Physical Review Bll, 2795–811.CrossRefGoogle Scholar
MacDowell, A.A., West, J.B., Greaves, G.N. and van der Laan, G. (1988) Monochromator and beamline for soft X-ray studies in the photon range 500 eV–5keV. Review of Scientific Instruments, 59, 843–52.CrossRefGoogle Scholar
Pollard, A.M., Spencer, M.S., Thomas, R.G., Williams, P.A., Holt, J. and Jennings, J.R. (1992) Georgeite and azurite as precursors in the preparation of coprecipitated copper-zinc oxide catalysts. Applied Catalysis A85, 111.Google Scholar
Porta, P., De Rossi, S., Ferraris, G. and Pompa, F. (1991) Characterization of copper-zinc mixed oxide system in relation to different precursor structure and morphology. Solid State Ionics, 45, 3541.CrossRefGoogle Scholar
Schofield, P.F., Henderson, Redfern, S.A.T. and van der Laan, G. (1993) Cu 2p absorption spectroscopy as a probe for site occupancy of (ZnxCui_x)WO4 solid solution. Phys. and Chem. of Minerals, 20, 375–81.CrossRefGoogle Scholar
Sengupta, G., Sharma, R.K., Sharma, V.B., Mishra, K.K., Kundu, M.L., Sanyal, R.M. and Dutta, S. (1995) Effect of incorporation of Al3+ ion on the structure of Cu-Zn coprecipitate. Journal of Solid State Chemistry, 115, 204–7.CrossRefGoogle Scholar
van der Laan, G., Pattrick, R.A.D., Henderson, C.M.B. and Vaughan, D.J. (1992) Oxidation state variations in copper minerals studied with Cu 2p X-ray absorption spectroscopy. Journal of Physics and Chemistry of Solids, 53, 1185–90.CrossRefGoogle Scholar