Anomalous site disorder in metal hydrides

Journal Article · Tue Jun 01 04:00:00 EDT 1982 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(82)90209-2· OSTI ID:6499117

Richards, P M

Existing measurements in fcc metal hydrides LaH/sub x/ and YH/sub x/ of intrinsic disorder x/sub 0/(2) (octahedral site occupation at the stoichiometric composition s = 2) appear to be highly inconsistent with one another by thermodynamic and spectroscopic techniques. The high-temperature thermodynamic data give x/sub 0/(2) approx. 0.01, while NMR, ESR, and neutron scattering have x/sub 0/(2) an order of magnitude larger at room temperature, while conventional wisdom indicates it should be less. This is explained by a model in which large-amplitude hydrogen vibrations at high temperature prevent occupation of both a tetrahedral and neighbor octahedral sites. Hence x/sub 0/(2) decreases at high temperature, and good agreement is found with reasonable values of the parameters.

• Research Organization: Sandia National Labs., Albuquerque, NM
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6499117
• Journal Information: J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 43:1; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
080201 -- Hydrogen-- Chemisorption Storage
36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
ELECTRON SPIN RESONANCE
FCC LATTICES
HYDRIDES
HYDROGEN COMPOUNDS
LANTHANUM COMPOUNDS
LANTHANUM HYDRIDES
MAGNETIC RESONANCE
MATHEMATICAL MODELS
NUCLEAR MAGNETIC RESONANCE
NUCLEAR MODELS
ORDER-DISORDER MODEL
RARE EARTH COMPOUNDS
RESONANCE
STOICHIOMETRY
TEMPERATURE EFFECTS
THERMODYNAMICS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM HYDRIDES