The novel borate Lu5Ba6B9O27 with a new structure type: synthesis, disordered crystal structure and negative linear thermal expansion

Stanislav K. Filatov, Yaroslav P. Biryukov, Rimma S. Bubnova, Andrey P. Shablinskii

Research output

Abstract

Single crystals of Lu5Ba6B9O27 were obtained by cooling from a melt and polycrystals of the borate were prepared using a multi-step solid-state synthesis. The crystal structure was determined from single-crystal X-ray diffraction data. The borate crystallizes in a new structure type in the monoclinic crystal system in space group C2/c, with cell parameters a = 13.0927 (3), b = 9.9970 (2) and c = 20.4884 (4) Å, β = 106.827 (1)°, V = 2566.86 (9) Å3 and Z = 4. It is described as a framework composed of rings consisting of vertex-sharing [BO3] triangles and [LuO6] octahedra. The Ba atoms are in the cavities of the framework. The structure is disordered: one of the B atoms is surrounded by six O atoms with partial occupancies of 0.5. The thermal properties of Lu5Ba6B9O27 were investigated by thermal analysis and high-temperature X-ray powder diffraction. Its thermal expansion is highly anisotropic. The negative expansion (contraction) is along the b axis, i.e. parallel to the planes of the largest number of [BO3] triangles. The coefficient of negative linear expansion ranges from −1.42 (at 20°C) to −5.57 × 10–6 °C–1 (at 1000°C). Thermal deformation of the ac plane is described in terms of the theory of shear deformation of monoclinic crystals. The Lu5Ba6B9O27 sample melts at 1170°C.
Original languageEnglish
Pages (from-to)697-703
JournalActa Crystallographica Section B: Structural Science, Crystal Engineering and Materials
Volume75
Issue number4
Early online date20 Jul 2019
Publication statusPublished - Aug 2019

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Borates
Hot Temperature
X-Ray Diffraction
Powder Diffraction
Temperature

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title = "The novel borate Lu5Ba6B9O27 with a new structure type: synthesis, disordered crystal structure and negative linear thermal expansion",
abstract = "Single crystals of Lu5Ba6B9O27 were obtained by cooling from a melt and polycrystals of the borate were prepared using a multi-step solid-state synthesis. The crystal structure was determined from single-crystal X-ray diffraction data. The borate crystallizes in a new structure type in the monoclinic crystal system in space group C2/c, with cell parameters a = 13.0927 (3), b = 9.9970 (2) and c = 20.4884 (4) {\AA}, β = 106.827 (1)°, V = 2566.86 (9) {\AA}3 and Z = 4. It is described as a framework composed of rings consisting of vertex-sharing [BO3] triangles and [LuO6] octahedra. The Ba atoms are in the cavities of the framework. The structure is disordered: one of the B atoms is surrounded by six O atoms with partial occupancies of 0.5. The thermal properties of Lu5Ba6B9O27 were investigated by thermal analysis and high-temperature X-ray powder diffraction. Its thermal expansion is highly anisotropic. The negative expansion (contraction) is along the b axis, i.e. parallel to the planes of the largest number of [BO3] triangles. The coefficient of negative linear expansion ranges from −1.42 (at 20°C) to −5.57 × 10–6 °C–1 (at 1000°C). Thermal deformation of the ac plane is described in terms of the theory of shear deformation of monoclinic crystals. The Lu5Ba6B9O27 sample melts at 1170°C.",
keywords = "lutetium barium borate, Crystal structure, negative thermal expansion (NTE), High-temperature X-ray powder diffraction (HTXRD)",
author = "Filatov, {Stanislav K.} and Biryukov, {Yaroslav P.} and Bubnova, {Rimma S.} and Shablinskii, {Andrey P.}",
year = "2019",
month = "8",
language = "English",
volume = "75",
pages = "697--703",
journal = "Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials",
issn = "2052-5192",
publisher = "International Union of Crystallography",
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TY - JOUR

T1 - The novel borate Lu5Ba6B9O27 with a new structure type: synthesis, disordered crystal structure and negative linear thermal expansion

AU - Filatov, Stanislav K.

AU - Biryukov, Yaroslav P.

AU - Bubnova, Rimma S.

AU - Shablinskii, Andrey P.

PY - 2019/8

Y1 - 2019/8

N2 - Single crystals of Lu5Ba6B9O27 were obtained by cooling from a melt and polycrystals of the borate were prepared using a multi-step solid-state synthesis. The crystal structure was determined from single-crystal X-ray diffraction data. The borate crystallizes in a new structure type in the monoclinic crystal system in space group C2/c, with cell parameters a = 13.0927 (3), b = 9.9970 (2) and c = 20.4884 (4) Å, β = 106.827 (1)°, V = 2566.86 (9) Å3 and Z = 4. It is described as a framework composed of rings consisting of vertex-sharing [BO3] triangles and [LuO6] octahedra. The Ba atoms are in the cavities of the framework. The structure is disordered: one of the B atoms is surrounded by six O atoms with partial occupancies of 0.5. The thermal properties of Lu5Ba6B9O27 were investigated by thermal analysis and high-temperature X-ray powder diffraction. Its thermal expansion is highly anisotropic. The negative expansion (contraction) is along the b axis, i.e. parallel to the planes of the largest number of [BO3] triangles. The coefficient of negative linear expansion ranges from −1.42 (at 20°C) to −5.57 × 10–6 °C–1 (at 1000°C). Thermal deformation of the ac plane is described in terms of the theory of shear deformation of monoclinic crystals. The Lu5Ba6B9O27 sample melts at 1170°C.

AB - Single crystals of Lu5Ba6B9O27 were obtained by cooling from a melt and polycrystals of the borate were prepared using a multi-step solid-state synthesis. The crystal structure was determined from single-crystal X-ray diffraction data. The borate crystallizes in a new structure type in the monoclinic crystal system in space group C2/c, with cell parameters a = 13.0927 (3), b = 9.9970 (2) and c = 20.4884 (4) Å, β = 106.827 (1)°, V = 2566.86 (9) Å3 and Z = 4. It is described as a framework composed of rings consisting of vertex-sharing [BO3] triangles and [LuO6] octahedra. The Ba atoms are in the cavities of the framework. The structure is disordered: one of the B atoms is surrounded by six O atoms with partial occupancies of 0.5. The thermal properties of Lu5Ba6B9O27 were investigated by thermal analysis and high-temperature X-ray powder diffraction. Its thermal expansion is highly anisotropic. The negative expansion (contraction) is along the b axis, i.e. parallel to the planes of the largest number of [BO3] triangles. The coefficient of negative linear expansion ranges from −1.42 (at 20°C) to −5.57 × 10–6 °C–1 (at 1000°C). Thermal deformation of the ac plane is described in terms of the theory of shear deformation of monoclinic crystals. The Lu5Ba6B9O27 sample melts at 1170°C.

KW - lutetium barium borate

KW - Crystal structure

KW - negative thermal expansion (NTE)

KW - High-temperature X-ray powder diffraction (HTXRD)

UR - https://onlinelibrary.wiley.com/iucr/doi/10.1107/S2052520619007443

M3 - Article

VL - 75

SP - 697

EP - 703

JO - Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials

JF - Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials

SN - 2052-5192

IS - 4

ER -