Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Résumé Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Clissold, M. E. Articles by Nickel, E. H. Search for Related Content GeoRef GeoRef Citation

THE STRUCTURE OF GILLARDITE, THE Ni-ANALOGUE OF HERBERTSMITHITE, FROM WIDGIEMOOLTHA, WESTERN AUSTRALIA

Meagan E. Clissold¹, Peter Leverett^1,, Peter A. Williams^1,, David E. Hibbs² and Ernest H. Nickel³

¹ School of Natural Sciences, University of Western Sydney, Locked Bag 1797, Penrith South DC NSW 1797, Australia
² Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
³ CSIRO Exploration and Mining, PO Box 5, Wembley, WA 6913, Australia

E-mail addresses: p.leverett{at}uws.edu.au, p.williams{at}uws.edu.au

The structure of gillardite, the Ni-analogue [ideally Cu₃NiCl₂(OH)₆] of herbertsmithite [ideally Cu₃ZnCl₂(OH)₆] has been determined at 273(2) K. The crystal used was removed from a sample from the 132N nickel deposit at Widgiemooltha, Western Australia, Australia. Seventeen electron-microprobe analyses gave compositions, based on a total of four cations per formula unit, that ranged from (Cu_3.189Ni_0.803Co_0.002Fe_0.006)Cl₂(OH)₆ to (Cu_2.922Ni_1.058Co_0.020)Cl₂(OH)₆, with an average result of all analyses of (Cu_3.081Ni_0.903Co_0.012Fe_0.004)Cl₂(OH)₆. The structure was refined using site occupancies indicated by the average composition, although refinement using the ideal composition gave identical results within standard errors. The new species gillardite is trigonal (rhombohedral), space group Rm, with a 6.8364(1), c 13.8459(4) Å, Z = 3. The oxysalt is isostructural with herbertsmithite, with the two different sites in the paratacamite-type structure being occupied by different cations [paratacamite is Cu₄Cl₂(OH)₆, space group R with a pronounced Rm substructure]. In gillardite, the Cu site is strongly Jahn–Teller-distorted, and the Ni site is regular with respect to Ni–O bond lengths, but with a slight angular distortion from regular octahedral geometry.

Keywords: gillardite, herbertsmithite, nickel analogue, new mineral species, paratacamite, crystal structure, Widgiemooltha, Western Australia.