Murphy, P.J. and Smith, Adrian M.L. and Hudson-Edwards, Karen A. and Dubbin, W.E. and Wright, K. (2009) Raman and IR spectroscopic studies of alunite-supergroup compounds containing AI, Cr3+, Fe3+ and V3+ at the B site. Canadian Mineralogist 47 (3), pp. 663-681. ISSN 0008-4476.
Abstract
Raman and IR spectroscopies, X-ray diffraction and chemical analysis have been used to characterize synthetic compounds of the alunite supergroup of formula AB3(SO4)2(OH)6, with A = Na+, K+, H3O+ and B = Al, Cr3+, Fe3+, V3+. For each A-site cation, the proportion of B-site vacancies decreases in the same order as the effective ionic radius of the B-site cations (Al > Cr > Fe > V). Raman and IR spectra of the compounds with B = Al and Fe3+ (alunite- and jarosite-group phases) show very close agreement with previously published spectra. The spectra for Cr- and V-based analogues show similarities to the alunite- and jarosite-group phases, and particularly the latter. The Raman and IR spectra are similar in the high-wavenumber ranges (around 3400–3500 cm–1), but are different in the intermediate and, particularly, the lower ranges, <700 cm–1, probably owing to the different responses of Raman and IR to SO4 and metal–O (M–O) group symmetries. The a parameter correlates well with {nu}1SO4, {nu}2SO4 and {nu}4SO4 Raman and {nu}4SO4 IR wavenumbers. There are differences in the OH-stretching regions, and shifts in the main {nu}SO4 and M–O peaks of the alunite-group phases, and Cr-, Fe- and V-based analogues with substitution of K, Na or H3O at the A site in the Raman and IR spectra. Raman and IR spectroscopies are therefore useful in distinguishing these compounds.
Metadata
| Item Type: | Article |
|---|---|
| Keyword(s) / Subject(s): | alunite supergroup, jarosite group, chromium, vanadium, Raman, infrared spectra, X-ray diffraction |
| School: | Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences |
| Depositing User: | Administrator |
| Date Deposited: | 09 Feb 2011 09:34 |
| Last Modified: | 02 Aug 2023 16:51 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/1800 |
Statistics
Additional statistics are available via IRStats2.
Archive Staff Only (login required)
