TY  - JOUR
A1  - Chariton, Stella
A1  - Bykov, Maxim
A1  - Bykova, Elena
A1  - Koemets, Egor
A1  - Fedotenko, Timofey
A1  - Winkler, Björn
A1  - Hanfland, Michael
A1  - Prakapenka, Vitali B.
A1  - Greenberg, Eran
A1  - McCammon, Catherine
A1  - Dubrovinsky, Leonid
T1  - The crystal structures of Fe-bearing MgCO3 sp2- and sp3-carbonates at 98 GPa from single-crystal X-ray diffraction using synchrotron radiation
T2  - Acta crystallographica. Section E, Crystallographic communications
N2  - 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.
KW  - carbonates
KW  - magnesite-II
KW  - sp3-carbonates
KW  - sp2-carbonates
KW  - crystal structure
KW  - high-pressure single-crystal X-ray diffraction
Y1  - 2020
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/54301
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-543014
SN  - 2056-9890
N1  - This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
VL  - 76
IS  - 5
SP  - 715
EP  - 719
PB  - International Union of Crystallography ; National Center for Biotechnology Information, U.S. National Library of Medicine
CY  - Chester ; Bethesda, MD
ER  -