Hydride phase composition and crystal structure in Zr/sub 2/PdH/sub x/

Conference · Wed Jan 01 00:00:00 EST 1986

OSTI ID:5817695

Spada, F E; Bowman, Jr, R C; Cantrell, J S

The ordered intermetallic Zr/sub 2/Pd forms several ternary hydride phases. The crystal structures of Zr/sub 2/PdH/sub x/ samples with various stoichiometries have been determined by powder x-ray diffraction methods. For samples with compositions between 1.68 less than or equal to x less than or equal to 2.2, the ternary hydrides possess the tetragonal MoSi/sub 2/-type structure of the original Zr/sub 2/Pd intermetallic but with expanded lattice parameters. However, the hydrides with greater than or equal to 2.9 have distorted MoSi/sub 2/ structures. Differences in proton occupancies among the various interstitial sites of the Zr/sub 2/Pd lattice are believed to be responsible for these variations in structure. This association is strongly supported by comparisons of the experimental second moments for the proton nuclear magnetic resonance (NMR) lineshapes with dipolar moments calculated for model tetragonal structures when samples have hydrogen compositions in the range 1.68 less than or equal to x less than or equal to 3.40. The NMR results clearly show that protons preferentially occupy tetrahedral interstitials when x less than or equal to 2.0 or the preparation temperature exceeds 700/sup 0/K. Additionally, we report the existence of the ternary hydride Zr/sub 2/PdH/sub 4.8/ at 298/sup 0/K and 36 atm H/sub 2/. 15 refs., 3 figs., 3 tabs.

• Research Organization: Kodak Research Labs., San Diego, CA (USA). Recording Systems Div.; Aerospace Corp., Los Angeles, CA (USA). Chemistry and Physics Lab.; Miami Univ., Oxford, OH (USA). Dept. of Chemistry
• DOE Contract Number: AC04-76DP00053
• OSTI ID: 5817695
• Report Number(s): MLM-3359-OP; CONF-8605114-3; ON: DE86011339
• Resource Relation: Conference: Properties and applications of metal hydrides, Maubuisson, France, 25 May 1986
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
INTERMETALLIC COMPOUNDS
HYDRIDATION
PALLADIUM COMPOUNDS
ZIRCONIUM COMPOUNDS
CHEMICAL COMPOSITION
NUCLEAR MAGNETIC RESONANCE
TETRAGONAL LATTICES
X-RAY DIFFRACTION
ALLOYS
CHEMICAL REACTIONS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
MAGNETIC RESONANCE
RESONANCE
SCATTERING
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties