CU AND ZN ORDERING IN AURICHALCITE

Citation
Jm. Charnock et al., CU AND ZN ORDERING IN AURICHALCITE, Mineralogical Magazine, 60(403), 1996, pp. 887-896
Citations number
16
Categorie Soggetti
Mineralogy
Journal title
ISSN journal
0026461X
Volume
60
Issue
403
Year of publication
1996
Pages
887 - 896
Database
ISI
SICI code
0026-461X(1996)60:403<887:CAZOIA>2.0.ZU;2-8
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 sa mples 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 t hat in each sample the copper might be distributed across more than on e metal site. EXAFS, at the Cu and Zn K-edges, shows that the copper a toms preferentially enter the Jahn-Teller elongated, octahedral (M2) a nd trigonal bipyramidal (M4) sites, with the zinc atoms entering the m ore regular octahedral (M1) and tetrahedral (M3) site. Substantial sol id solution towards the zinc rich region is facilitated by the substit ution of copper by zinc on the M2 and M4 sites. This information, not easily obtained by X-ray diffraction, substantially enhances the under standing of the structure of aurichalcite.