TY - JOUR

T1 - Thermal behavior of uranyl selenite minerals derriksite and demesmaekerite

AU - Gurzhiy, Vladislav V.

AU - Izatulina, Alina R.

AU - Krzhizhanovskaya, Maria G.

AU - Murashko, Mikhail N.

AU - Spiridonova, Dar’Ya V.

AU - Shilovskikh, Vladimir V.

AU - Krivovichev, Sergey V.

N1 - Funding Information: Acknowledgments. This research was funded by the Russian Science Foundation (grant 18-17-00018). The XRD and EDX measurements have been performed at the X-ray Diffraction Centre and “Geomodel” Research Centre of the St. Petersburg State University. We are grateful to two anonymous reviewers for useful comments. Publisher Copyright: © 2020, Czech Geological Survey. All rights reserved. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2020/12/15

Y1 - 2020/12/15

N2 - Crystal structures of two uranyl selenite minerals derriksite, Cu4 [(UO2)(SeO3)2 ](OH)6, and demesmaekerite, Pb2 Cu5 [(UO2)2 (SeO3)6 (OH)6 ](H2 O)2, which structures are based on uranyl selenite 1D structural units, were studied employing single-crystal X-ray diffraction analysis at various temperatures. The refinement of their crystal structures reveals the detailed dynamics of the interatomic interactions during the heating process, which allows describing the thermal behavior. Uranyl selenite chains and their mutual arrangement mainly provide the rigidity of the crystal structure. Thus the lowest expansion in the structure of derriksite is observed along the direction of uranyl selenite chains, while the largest expansion occurs in the direction normal to chains, with the space occupied by lone electron pairs of Se4+ atoms and low covalent bond distribution density. The maximal expansion in the crystal structure of demesmaekerite is manifested approximately along the [100], which matches the direction of chains of less strongly bonded Cu-centered octahedra, and gaps between Cu chains occupied by the Pb cations. The crystal structure of demesmaekerite undergoes contraction in the direction of the space between the U-bearing chains with the deficiency of strong covalent bonds. Contraction of the structure can also be attributed to the orthogonalization of the oblique triclinic angles of the unit cell. It is demonstrated that the assignment of U-bearing units during structure description is reasonably justified since, regardless of their dimensionality, these substructural units are one of the most stable and rigid blocks in the structural architecture, and they govern the thermal behavior of the entire structure.

AB - Crystal structures of two uranyl selenite minerals derriksite, Cu4 [(UO2)(SeO3)2 ](OH)6, and demesmaekerite, Pb2 Cu5 [(UO2)2 (SeO3)6 (OH)6 ](H2 O)2, which structures are based on uranyl selenite 1D structural units, were studied employing single-crystal X-ray diffraction analysis at various temperatures. The refinement of their crystal structures reveals the detailed dynamics of the interatomic interactions during the heating process, which allows describing the thermal behavior. Uranyl selenite chains and their mutual arrangement mainly provide the rigidity of the crystal structure. Thus the lowest expansion in the structure of derriksite is observed along the direction of uranyl selenite chains, while the largest expansion occurs in the direction normal to chains, with the space occupied by lone electron pairs of Se4+ atoms and low covalent bond distribution density. The maximal expansion in the crystal structure of demesmaekerite is manifested approximately along the [100], which matches the direction of chains of less strongly bonded Cu-centered octahedra, and gaps between Cu chains occupied by the Pb cations. The crystal structure of demesmaekerite undergoes contraction in the direction of the space between the U-bearing chains with the deficiency of strong covalent bonds. Contraction of the structure can also be attributed to the orthogonalization of the oblique triclinic angles of the unit cell. It is demonstrated that the assignment of U-bearing units during structure description is reasonably justified since, regardless of their dimensionality, these substructural units are one of the most stable and rigid blocks in the structural architecture, and they govern the thermal behavior of the entire structure.

KW - Crystal structure

KW - Demesmaekerite

KW - Derriksite

KW - Selenite

KW - Thermal expansion

KW - Uranyl

UR - http://www.scopus.com/inward/record.url?scp=85098778521&partnerID=8YFLogxK

U2 - 10.3190/jgeosci.315

DO - 10.3190/jgeosci.315

M3 - Article

AN - SCOPUS:85098778521

VL - 65

SP - 249

EP - 259

JO - Journal of Geosciences

JF - Journal of Geosciences

SN - 1802-6222

IS - 4

ER -