Title of article
The crystal structures of Fe-bearing MgCO3 sp2- and sp3-carbonates at 98 GPa from single-crystal X-ray diffraction using synchrotron radiation
Author/Authors
Chariton, Stella Bayerisches Geoinstitut - University of Bayreuth, Germany , Bykov, Maxim Bayerisches Geoinstitut - University of Bayreuth, Germany , Bykova, Elena Deutsches Elektronen-Synchrotron (DESY), Germany , Koemets, Egor Bayerisches Geoinstitut - University of Bayreuth, Germany , Fedotenko, Timofey Material Physics and Technology at Extreme Conditions - Laboratory of Crystallography - University of Bayreuth, Germany , Winkler, Björn Institute of Geosciences - Goethe University, Germany , Hanfland, Michael European Synchrotron Radiation Facility, France , Prakapenka, Vitali B. GeoSoilEnviroCARS, University of Chicago, USA , Greenberg, Eran GeoSoilEnviroCARS, University of Chicago, USA , McCammon, Catherine Bayerisches Geoinstitut - University of Bayreuth, Germany , Fedotenko, Timofey Material Physics and Technology at Extreme Conditions - Laboratory of Crystallography - University of Bayreuth, Germany
Pages
11
From page
1
To page
11
Abstract
The crystal structure of MgCO3-II has long been discussed in the literature where DFT-based model calculations predict a pressure-induced transition of the carbon atom from the sp2 to the sp3 type of bonding. We have now determined the crystal structure of iron-bearing MgCO3-II based on single-crystal X-ray diffraction measurements using synchrotron radiation. We laser-heated a synthetic (Mg0.85Fe0.15)CO3 single crystal at 2500 K and 98 GPa and observed the formation of a monoclinic phase with composition (Mg2.53Fe0.47)C3O9 in the space group C2/m that contains tetrahedrally coordinated carbon, where CO44− tetrahedra are linked by corner-sharing oxygen atoms to form three-membered C3O96− ring anions. The crystal structure of (Mg0.85Fe0.15)CO3 (magnesium iron carbonate) at 98 GPa and 300 K is reported here as well. In comparison with previous structure-prediction calculations and powder X-ray diffraction data, our structural data provide reliable information from experiments regarding atomic positions, bond lengths, and bond angles.
Keywords
carbonates , magnesite-II , sp3-carbonates , high-pressure single-crystal X-ray diffraction , crystal structure
Journal title
Acta Crystallographica Section E: Crystallographic Communications
Serial Year
2020
Record number
2624070
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