Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Mineralogical Magazine Don't get GSW? Talk to your librarian.
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Mineralogical Magazine; April 2006; v. 70; no. 2; p. 187-199; DOI: 10.1180/0026461067020323
© 2006 Mineralogical Society of Great Britain and Ireland
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ferrow, E. A.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

57Fe Mössbauer effect study of bannisterite: a modulated 2:1-type phyllosilicate

E. A. Ferrow*

GeoBiosphere Science Centre, Department of Geology, Lithosphere Biosphere Science, Lund University, Sölvegatan 12, S-223 62 Lund, Sweden

* E-mail: embaie.ferrow{at}geol.lu.se

Bannisterite is a modulated 2:1-type phyllosilicate having ten octahedral sites with hydroxyl groups in trans, cis and combined trans-cis configurations. Each octahedral site, depending on its proximity to the layer modulation, is exposed to a different degree of distortion. The electric field gradient at the Fe site and the site distortion are used to propose a model for the site assignment and oxidation mechanism in bannisterite. The results show that two models are compatible with the experimental results of fitting the spectrum of bannisterite. However, the model which allows for site distortion accounts better for the observed line overlap of the [6]Fe2+ sites. Accordingly, the octahedral sites with a greater degree of distortion are assigned to the [6]Fe2+ with lower electric quadrupole splitting, and the octahedral sites with lower site distortion are assigned to the [6]Fe2+ with higher electric quadrupole splitting. Moreover, the ease of oxidation decreases in the order trans > trans-cis > cis.

KEYWORDS: bannisterite, Mössbauer, distortion, electric field gradient, site assignment






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 by Mineralogical Society of Great Britain and Ireland