TY - JOUR

T1 - Crystal structure and strong uniaxial negative thermal expansion of CaBi2B2O7 borate

AU - Volkov, Sergey

AU - Bubnova, Rimma

AU - Shorets, Olga

AU - Ugolkov, Valery

AU - Filatov, Stanislav

N1 - Funding Information: The authors are grateful to Dr. M.G. Krzhizhanovskaya (Institute of Earth Sciences, Department of Crystallography, Saint Petersburg State University ) for conducting the high temperature X-ray powder diffraction experiment. This work was financially supported by the Russian Foundation for Basic Research through the grant 18-03-00679 . X-ray powder diffraction experiments were performed at the Centre for X-ray Diffraction Studies, Research Park, Saint-Petersburg State University . Funding Information: The authors are grateful to Dr. M.G. Krzhizhanovskaya (Institute of Earth Sciences, Department of Crystallography, Saint Petersburg State University) for conducting the high temperature X-ray powder diffraction experiment. This work was financially supported by the Russian Foundation for Basic Research through the grant 18-03-00679. X-ray powder diffraction experiments were performed at the Centre for X-ray Diffraction Studies, Research Park, Saint-Petersburg State University. Publisher Copyright: © 2020 Elsevier B.V. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/12

Y1 - 2020/12

N2 - The single crystal of CaBi2B2O7 was obtained by recrystallization in solid-state and studied by single-crystal X-ray diffraction. Its crystal structure was refined in the centrosymmetric orthorhombic space group Pnma with a = 8.5556(8) Å, b = 5.1569(5) Å, c = 9.6677(7) Å, Z = 4. The structure is based upon parallel (0 1 0) {CaBi2B2O7}∞ layers from BO3 triangles, ψ-tetrahedral BiO3 groups, and CaO6 triangular prisms connected each to other via long and weak Bi–O bonds. This borate is representative of MBi2B2O7 family (M = Ca, Sr, Ba), where all members can be obtained from the hypothetical hexagonal aristotype. Thermal expansion is studied by high-temperature X-ray powder diffraction, its strongly anisotropic and negative along [0 0 1]: αa = 11.8(1) × 10−6 °C−1, αb = 34.2(3) × 10−6 °C−1, αc = –25.7(4) × 10−6 °C−1 at 600 °C. As a result, a/c cell parameters ratio tends to ideal √3 value, corresponding to the hexagonal aristotype.

AB - The single crystal of CaBi2B2O7 was obtained by recrystallization in solid-state and studied by single-crystal X-ray diffraction. Its crystal structure was refined in the centrosymmetric orthorhombic space group Pnma with a = 8.5556(8) Å, b = 5.1569(5) Å, c = 9.6677(7) Å, Z = 4. The structure is based upon parallel (0 1 0) {CaBi2B2O7}∞ layers from BO3 triangles, ψ-tetrahedral BiO3 groups, and CaO6 triangular prisms connected each to other via long and weak Bi–O bonds. This borate is representative of MBi2B2O7 family (M = Ca, Sr, Ba), where all members can be obtained from the hypothetical hexagonal aristotype. Thermal expansion is studied by high-temperature X-ray powder diffraction, its strongly anisotropic and negative along [0 0 1]: αa = 11.8(1) × 10−6 °C−1, αb = 34.2(3) × 10−6 °C−1, αc = –25.7(4) × 10−6 °C−1 at 600 °C. As a result, a/c cell parameters ratio tends to ideal √3 value, corresponding to the hexagonal aristotype.

UR - http://www.scopus.com/inward/record.url?scp=85091791849&partnerID=8YFLogxK

U2 - 10.1016/j.inoche.2020.108262

DO - 10.1016/j.inoche.2020.108262

M3 - Article

AN - SCOPUS:85091791849

VL - 122

JO - Inorganic Chemistry Communication

JF - Inorganic Chemistry Communication

SN - 1387-7003

M1 - 108262

ER -