High-pressure synthesis, crystal structure, and properties of the first ternary hafniumborate {beta}-HfB{sub 2}O{sub 5}
- Department Chemie und Biochemie, Ludwig-Maximilians-Universitaet Muenchen, Butenandtstrasse 5-13, D-81377 Munich (Germany)
The first ternary hafniumborate {beta}-HfB{sub 2}O{sub 5} was synthesized under high-pressure and high-temperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 1100 deg. C. The monoclinic hafnium-diborate crystallizes with four formula units in the space group P2{sub 1}/c with lattice parameters a=438.48(9), b=690.60(2), c=897.60(2) pm, and {beta}=90.76(3){sup o}. Due to the fact that high-pressure conditions favour the fourfold-coordination of boron, a structure is observed, which is built up exclusively from layers of BO{sub 4} tetrahedra; between the layers, the hafnium ions are coordinated square-antiprismatically by eight oxygen atoms. A structural comparison of {beta}-HfB{sub 2}O{sub 5} with minerals of the gadolinite-homilite-hingganite-datolite family proved this compound to be the simplest structural variant in this structure type, known so far. Along with a structural discussion, temperature-programmed X-ray powder diffraction data are shown, demonstrating the metastable character of this compound. - Graphical abstract: Synthesis of {beta}-HfB{sub 2}O{sub 5} via the multianvil high-pressure/high-temperature technique, representing the first ternary compound in the borate system Hf-B-O.
- OSTI ID:
- 21015705
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 2; Other Information: DOI: 10.1016/j.jssc.2006.12.005; PII: S0022-4596(06)00637-2; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
Similar Records
High-pressure synthesis, crystal structure, and structural relationship of the first ytterbium fluoride borate Yb{sub 5}(BO{sub 3}){sub 2}F{sub 9}
Pr{sub 4}B{sub 10}O{sub 21}: A new composition of rare-earth borates by high-pressure/high-temperature synthesis