Structure and vibrational dynamics of isotopically labeled lithium borohydride using neutron diffraction and spectroscopy
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-8562 (United States)
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (United States)
The crystalline structure of a {sup 7}Li and {sup 11}B labeled lithium borohydride has been investigated using neutron powder diffraction at 3.5, 360, and 400 K. The B-H bond lengths and H-B-H angles for the [BH{sub 4}]{sup -} tetrahedra indicated that the tetrahedra maintained a nearly ideal configuration throughout the temperature range investigated. The atomic displacement parameters at 360 K suggest that the [BH{sub 4}]{sup -} tetrahedra become increasingly disordered as a result of large amplitude librational and reorientational motions as the orthorhombic to hexagonal phase transition (T=384 K) is approached. In the high-temperature hexagonal phase, the [BH{sub 4}]{sup -} tetrahedra displayed extreme disorder about the trigonal axis along which they are aligned. Neutron vibrational spectroscopy data were collected at 5 K over an energy range of 10-170 meV, and were found to be in good agreement with prior Raman and low-resolution neutron spectroscopy studies. - Graphical abstract: The structure of {sup 7}Li{sup 11}BH{sub 4} in the low-temperature Pnma phase, including atomic displacement ellipsoids, at 3.5 K.
- OSTI ID:
- 21015777
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 4; Other Information: DOI: 10.1016/j.jssc.2007.01.031; PII: S0022-4596(07)00073-4; Copyright (c) 2007 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
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ATOMIC DISPLACEMENTS
BOND LENGTHS
BOROHYDRIDES
BORON HYDRIDES
CRYSTAL-PHASE TRANSFORMATIONS
HEXAGONAL LATTICES
HYDROGEN STORAGE
LITHIUM COMPOUNDS
MEV RANGE 01-10
MEV RANGE 10-100
MEV RANGE 100-1000
NEUTRON DIFFRACTION
NEUTRON SPECTROSCOPY
NUCLEAR MAGNETIC RESONANCE
ORTHORHOMBIC LATTICES
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K