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Bonding and structural changes in siderite at high pressure

Gabriela Farfan, Shibing Wang, Hongwei Ma, Razvan Caracas and Wendy L. Mao
Bonding and structural changes in siderite at high pressure
American Mineralogist (August 2012) 97 (8-9): 1421-1426


Understanding the physical and chemical properties of carbonate minerals at extreme conditions is important for modeling the deep carbon cycle, because they represent likely hosts for carbon in the lower mantle. Previous high-pressure studies have identified a structural and electronic phase transition in siderite using X-ray diffraction and X-ray emission spectroscopy. The Fe end-member of the carbonate group, siderite (FeCO (sub 3) ), exhibits unique high-pressure behavior that we investigated using a combination of in situ Raman spectroscopy, synchrotron X-ray diffraction, and theoretical methods. In this Raman spectroscopy study, we observed the appearance of a new CO (sub 3) symmetric stretching mode at 20 cm (super -1) lower frequency beginning at approximately 46 GPa. This softening is due to the lengthening of the C-O bonds as a result of a combination of rotation and volume shrinkage of the FeO (sub 6) octahedra while siderite undergoes the isostructural volume collapse and electronic spin transition.

ISSN: 0003-004X
EISSN: 1945-3027
Serial Title: American Mineralogist
Serial Volume: 97
Serial Issue: 8-9
Title: Bonding and structural changes in siderite at high pressure
Affiliation: Stanford University, Geological and Environmental Sciences, Stanford, CA, United States
Pages: 1421-1426
Published: 201208
Text Language: English
Publisher: Mineralogical Society of America, Washington, DC, United States
References: 29
Accession Number: 2012-079909
Categories: Geophysics of minerals and rocks
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
Secondary Affiliation: Ecole Normale Superieure de Lyon, FRA, France
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Mineralogical Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201242
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