High-Pressure Raman and X-ray Diffraction Study of [beta]- and [gamma]-Polymorphs of Aluminum Hydride

Journal Article · Mon Mar 26 04:00:00 EDT 2012 · J. Phys. Chem. C

DOI:https://doi.org/10.1021/jp204925w· OSTI ID:1035381

Drozd, Vadym; Garimella, Subrahmanyam; Saxena, Surendra; Chen, Jiuhua; Palasyuk, Taras ^[1]

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1. FIU

Three polymorphs of alane, AlH{sub 3}, ({alpha}, {beta}, and {gamma}) were synthesized and studied at high-pressure in diamond anvil cell by Raman spectroscopy and synchrotron X-ray diffraction. According to synchrotron X-ray diffraction study, {beta}-AlH{sub 3} is stable up to 6 GPa, followed by transformation into {alpha} phase at higher pressures. X-ray-induced decomposition {gamma}-AlH{sub 3} into constituent elements was found at 15 GPa. Raman scattering study at high pressure for both {beta}- and {gamma}-AlH{sub 3} reveals transition into the {alpha} phase with high concentration of structural defects. DFT calculations (VASP code) show that instability of cubic {beta}-alane crystal structure at high pressure is caused by the strong deformation of the [AlH{sub 6}] polyhedra.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: DOE - BASIC ENERGY SCIENCESOTHER U.S. STATES
• OSTI ID: 1035381
• Journal Information: J. Phys. Chem. C, Journal Name: J. Phys. Chem. C Journal Issue: (5) ; 02, 2012 Vol. 116; ISSN 1932-7447
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALUMINIUM
CRYSTAL STRUCTURE
DEFECTS
DEFORMATION
DIAMONDS
HYDRIDES
INSTABILITY
RAMAN SPECTROSCOPY
SCATTERING
SYNCHROTRONS
TRANSFORMATIONS
X-RAY DIFFRACTION