The new high-pressure borate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O-Formation of edge-sharing BO{sub 4} tetrahedra in a hydrated borate

Journal Article · Sun Jan 15 04:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.10.028· OSTI ID:21612842

Neumair, Stephanie C ^[1]; Kaindl, Reinhard ^[2]; Huppertz, Hubert ^[1]

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1. Institut fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52a, A-6020 Innsbruck (Austria)
2. Institut fuer Mineralogie und Petrographie, Leopold-Franzens-Universitaet Innsbruck, Innrain 52f, A-6020 Innsbruck (Austria)

The new borate hydrate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O was synthesized under high-pressure/high-temperature conditions of 6 GPa and 880 Degree-Sign C in a Walker-type multianvil apparatus. The compound crystallizes in the orthorhombic space group Pbam (Z=2) with the lattice parameters a=819.0(2), b=2016.9(4), c=769.9(2) pm, V=1.2717(4) nm{sup 3}, R{sub 1}=0.0758, wR{sub 2}=0.0836 (all data). The new structure type of Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O is built up from corner-sharing BO{sub 4} tetrahedra forming corrugated layers, that are interconnected among each other by two edge-sharing BO{sub 4} tetrahedra (B{sub 2}O{sub 6} units) forming Z-shaped channels. Interestingly, the here presented structure of Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O is closely related to the structures of M{sub 6}B{sub 22}O{sub 39}{center_dot}H{sub 2}O (M=Fe, Co), which exhibit BO{sub 4} tetrahedra in an intermediate state on the way to edge-sharing BO{sub 4} tetrahedra. - Graphical Abstract: The new high-pressure borate hydrate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O is built up from corner-sharing BO{sub 4} tetrahedra forming corrugated layers, that are interconnected among each other by two edge-sharing BO{sub 4} tetrahedra (B{sub 2}O{sub 6} units). In this paper we report on synthesis, structural details, and properties of the new compound Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O. Highlights: Black-Right-Pointing-Pointer High-pressure/high-temperature synthesis of the new borate hydrate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O. Black-Right-Pointing-Pointer In the structure of Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O, two B{sub 2}O{sub 6} units are connected to 'vierer' rings. Black-Right-Pointing-Pointer Pressure favours the formation of edge-sharing BO{sub 4} tetrahedra in the chemistry of borates.

• OSTI ID: 21612842
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 185; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BORATES
BORON COMPOUNDS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
HYDRATES
HYDROGEN COMPOUNDS
INTERMEDIATE STATE
LATTICE PARAMETERS
LAYERS
ORTHORHOMBIC LATTICES
OXYGEN COMPOUNDS
PRESSURE RANGE
PRESSURE RANGE GIGA PA
PRESSURE RANGE MEGA PA
PRESSURE RANGE MEGA PA 10-100
SPACE GROUPS
SYMMETRY GROUPS
SYNTHESIS
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
WATER