Crystal structure of lithium beryllium hydride

Journal Article · Thu Jan 01 00:00:00 EST 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.35.411· OSTI ID:6883514

Overhauser, A W

Analysis of powder diffraction data, published by Bell and Coates, reveals that LiBeH/sub 3/ and Li/sub 2/BeH/sub 4/ both have an fcc translation group with lattice constants 5.09 and 5.14 A, respectively. The cubic cell of each contains eight formula units; so the total atomic concentrations, 3.03 x 10/sup 23/ and 4.12 x 10/sup 23/ cm/sup -3/, exceed that of diamond by factors of 1.7 and 2.3. The computed densities are 1.91 and 2.63 g/cm/sup 3/. Both crystals have a modified perovskite structure involving cubes with edges half the size of the lattice constant. The (otherwise) sc lattice is broken by a chemical superstructure in LiBeH/sub 3/ and by an orientational superstructure in Li/sub 2/BeH/sub 4/. The ''conduction''-electron density of the latter is 4.71 x 10/sup 23/ cm/sup 3/; so the equivalent-sphere-radius parameter is r/sub s/ = 1.51 Bohr, a value in the range typically assumed for metallic hydrogen. Infrared absorption at 1600 cm/sup -1/ (approx. =2300 K) was reported. Consequently, these compounds, if metallic, may manifest the high-temperature superconductivity often envisioned for metallic hydrogen.

• Research Organization: Department of Physics, Purdue University, West Lafayette, Indiana 47907
• OSTI ID: 6883514
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 35:1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BERYLLIUM HYDRIDES
CRYSTAL STRUCTURE
LITHIUM HYDRIDES
ABSORPTION SPECTRA
INFRARED SPECTRA
LATTICE PARAMETERS
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BERYLLIUM COMPOUNDS
COHERENT SCATTERING
DIFFRACTION
HYDRIDES
HYDROGEN COMPOUNDS
LITHIUM COMPOUNDS
SCATTERING
SPECTRA
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies