The crystal structures of Fe-bearing MgCO3 sp2- and sp3-carbonates at 98 GPa from single-crystal X-ray diffraction using synchrotron radiation

  • 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.

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Author:Stella CharitonORCiDGND, Maxim BykovORCiDGND, Elena BykovaORCiDGND, Egor KoemetsORCiDGND, Timofey FedotenkoORCiDGND, Björn WinklerORCiDGND, Michael Hanfland, Vitali B. PrakapenkaORCiD, Eran Greenberg, Catherine McCammon, Leonid DubrovinskyORCiDGND
Pubmed Id:
Parent Title (English):Acta crystallographica. Section E, Crystallographic communications
Publisher:International Union of Crystallography ; National Center for Biotechnology Information, U.S. National Library of Medicine
Place of publication:Chester ; Bethesda, MD
Contributor(s):M. Weil
Document Type:Article
Year of Completion:2020
Date of first Publication:2020/04/21
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2020/06/24
Tag:carbonates; crystal structure; high-pressure single-crystal X-ray diffraction; magnesite-II; sp2-carbonates; sp3-carbonates
Page Number:11
First Page:715
Last Page:719
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.
Institutes:Geowissenschaften / Geographie / Geowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Licence (German):License LogoCreative Commons - Namensnennung 4.0