Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
American Mineralogist Email Content Delivery
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
American Mineralogist; November 2007; v. 92; no. 11-12; p. 1912-1918; DOI: 10.2138/am.2007.2585
© 2007 Mineralogical Society of America
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 Martin, C. D.
Right arrow Articles by Parise, J. B.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

High-pressure structure and bonding in CaIrO3: The structure model of MgSiO3 post-perovskite investigated with time-of-flight neutron powder diffraction

C. David Martin1,*, Ronald I. Smith2, William G. Marshall2 and John B. Parise1,3

1 Geosciences Department, 255 Earth and Space Sciences Building, Stony Brook University, Stony Brook, New York 11794-2100, USA
2 ISIS Neutron Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK
3 Chemistry Department, Stony Brook University, Stony Brook, New York 11794-3400, USA

Correspondence: * E-mail: martin{at}anl.gov

The structure of CaIrO3 (Cmcm) has been refined at high pressure and at low temperature using time-of-flight neutron powder diffraction data. Evidence supporting deviation from space group Cmcm to Cmc21 is inconclusive. As CaIrO3 (Cmcm) unit-cell volume changes, refinements indicate deformation of cation-centered coordination polyhedra, rather than tilting. Structure models demonstrate Ca2+-centered polyhedra are an order of magnitude more compressible than Ir4+-centered octahedra. Bond valence sums show significant chemical strain (over-bonding) of calcium and oxygen at ambient conditions. Implications for structure change in MgSiO3 post-perovskite are discussed and a method for predicting the Clapeyron slope between perovskite and post-perovskite phases is proposed based on extrapolation of the volume-ratio between cation-centered polyhedra.

Key Words: Post-perovskite • high pressure • structure • neutron diffraction • Rietveld refinement • bond valence • D'' layer • CaIrO3






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 by Mineralogical Society of America