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A single crystal X-ray study of a sulphate-bearing buttgenbachite, Cu36Cl7.8(NO3)1.3(SO4)0.35(OH)62.2.5.2H2O, and a re-examination of the crystal chemistry of the buttgenbachite-connellite series

Published online by Cambridge University Press:  05 July 2018

D. E. Hibbs ,
P. Leverett  and
P. A. Williams
D. E. Hibbs
Affiliation:
School of Chemistry, University of Sydney, NSW 2006, Australia
P. Leverett*
Affiliation:
Minerals and Materials Group, School of Science, Food and Horticulture, University of Western Sydney, Locked Bag 1797, Penrith South DC NSW 1797, Australia
P. A. Williams
Affiliation:
Minerals and Materials Group, School of Science, Food and Horticulture, University of Western Sydney, Locked Bag 1797, Penrith South DC NSW 1797, Australia
*
* E-mail: p.leverett@uws.edu.au
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Abstract

The single-crystal X-ray structure of a sulphate-bearing buttgenbachite, Cu36Cl7.8(NO3)1.3(SO4)0.35(OH)62.2.5.2H2O, from Likasi, Democratic Republic of Congo, has been determined at 100 and 288 K. The basic framework of the structure is the same as has been previously reported for buttgenbachite, except for the identification of a hydrogen-bonded chloride ion (occupancy 0.6) at the origin instead of a Cu ion with partial occupancy. The nature of nitrate positional disorder along channels in the c direction and how this relates to the presence of other species such as chloride ions and water molecules and, most importantly, sulphate ions has been elucidated. One nitrate ion, with an occupancy of 0.18, lies at 2/3,l/3,l/4 and shares the site with a chloride ion (occupancy 0.30) and also a sulphate ion (occupancy 0.09); a second nitrate, with an occupancy of 0.24, lies at 2/3,1/3,0.084 and shares the site with a water molecule (occupancy 0.06). As a result, a formula of Cu36Cl7.8(NO3)1.3(SO4)0.35(OH)62.2.5.2H2O is obtained. Re-refinement of deposited data for a supposed connellite crystal from the Toughnut mine,Tombstone, Arizona gives a related, but different, pattern of anion substitution. No sulphate could be detected in the structure and it is evident that this structure refers to buttgenbachite. A nitrate nitrogen atom and a chloride ion are disordered at 2/3,l/3,l/4, the overall site being fully occupied. A chloride ion with ∼0.5 occupancy is sited at the origin and the formula Cu36Cl7.9(NO3)1.1(OH)63.4H2O is indicated. Re-refinement of a deposited data set for another buttgenbachite crystal from the Likasi mine reveals a partially occupied nitrate centred at 2/3,l/3, z and a partially occupied chloride at 2/3,l/3,l/4. Either 0.5Cl–, OH–, H2O or H3O+ is located at the origin. If the latter is the case, the stoichiometry for this buttgenbachite is Cu36Cl6.5(NO3)1.5(OH)64.5.5H2O. The present study has highlighted the fact that a range of compositions for buttgenbachite exists, depending on the pH and relative activities of chloride, nitrate and sulphate ions in solutions from which the mineral crystallizes.

Keywords

buttgenbachiteconnellitesolid solutionsubstitutionX-ray structure.
Type
Research Article
Information
Mineralogical Magazine , Volume 67 , Issue 1 , February 2003 , pp. 47 - 60
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2003

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References

Anthony, J.W., Williams, S.A., Bideaux, R.A. and Grant, R.W. (1995) Mineralogy of Arizona, 3rd edition. University of Arizona Press, Tucson, p. 103.Google Scholar
Bruker (1995) SMART, SAINT and XPREP. Area detector control, data integration and reduction software. Bruker Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.Google Scholar
Fanfani, L., Nunzi, A., Zanazzi, P.F. and Zanzari, A.R. (1973) The crystal structure of buttgenbachite. Mineralogical Magazine, 39, 264—270CrossRefGoogle Scholar
Ford, W.E. and Bradley, W.M. (1915) On the identity of footeite with connellite together with the description of two new occurrences of the mineral. American Journal of Science, 39, 670—676CrossRefGoogle Scholar
Mandarino, J.A. (1999) Fleischer,s Glossary of Mineral Species 1999. Mineralogical Record, Tucson, Arizona, USA.Google Scholar
McLean, W.J. and Anthony, J.W. (1972) The disordered, ‘zeolite-like’ structure of connellite. American Mineralogist, 57, 426—438Google Scholar
Palache, C., Berman, H. and Frondel, C. (1951) The System of Mineralogy Volume II, 7th edition. John Wiley & Sons, New York, pp. 572—573.Google Scholar
Pollard, A.M., Thomas, R.G., Williams, P.A., Bevins, R.E. and T, urgoose (1989) Carbonatian connellite, a new variety, from the Britannia mine, North Wales, and from the Botallack mine, Cornwall. Journal of the Russell Society, 2, 23—27Google Scholar
Pollard, A.M., Thomas, R.G. and Williams, P.A. (1990) Connellite: stability relationships with other secondary copper minerals. Mineralogical Magazine, 54, 425—430CrossRefGoogle Scholar
Sharpe, J.L. (1998) Chemical Mineralogy of Supergene Copper Deposits of the Cloncurry District, northwest Queensland. M.Sc. thesis, University of Western Sydney.Google Scholar
Sheldrick, G.M. (1990) Phase annealing in SHELX-90: direct methods for larger structures. Acta Crystallographica, A46, 467—473CrossRefGoogle Scholar
Sheldrick, G.M. (1996) SADABS. Empirical absorption correction program for area detector data. University of Gottingen, Germany.Google Scholar
Sheldrick, G.M. (1997) SHELXL-97. A programfor the refinement of crystal structures. University of Göttingen, Germany.Google Scholar
Walker, N. and Stuart, D. (1983) An empirical method for correcting diffractometer data for absorption effects. Acta Crystallographica , A39, 158—166CrossRefGoogle Scholar
Williams, P.A. (1990) Oxide Zone Geochemistry. Ellis Horwood, Chichester.Google Scholar
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