Structural Phase Transitions of Mg(BH[subscript 4])[subscript 2] under Pressure

Journal Article · Fri Jan 23 04:00:00 EST 2009 · J. Phys. Chem. C

DOI:https://doi.org/10.1021/jp807842t· OSTI ID:1005448

George, Lyci; Drozd, Vadym; Saxena, Surendra K; Bardaji, Elisa Gil; Fichtner, Maximilian

The structural stability of Mg(BH{sub 4}){sub 2}, a promising hydrogen storage material, under pressure has been investigated in a diamond anvil cell up to 22 GPa with combined synchrotron X-ray diffraction and Raman spectroscopy. The analyses show a structural phase transition around 2.5 GPa and again around 14.4 GPa. An ambient-pressure phase of Mg(BH{sub 4}){sub 2} has a hexagonal structure (space group P61, a = 10.047(3) {angstrom}, c = 36.34(1) {angstrom}, and V = 3176(1) {angstrom}{sup 3} at 0.2 GPa), which agrees well with early reports. The structure of high-pressure phase is found to be different from reported theoretical predictions; it also does not match the high-temperature phase. The high-pressure polymorph of Mg(BH{sub 4}){sub 2} is found to be stable on decompression, similar to the case of the high-temperature phase. Raman spectroscopic study shows a similarity in high-pressure behavior of as-prepared Mg(BH{sub 4}){sub 2} and its high-temperature phase.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE
• OSTI ID: 1005448
• Journal Information: J. Phys. Chem. C, Journal Name: J. Phys. Chem. C Journal Issue: (1) ; 2009 Vol. 113; ISSN 1932-7447
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

08 HYDROGEN
43 PARTICLE ACCELERATORS
DIAMONDS
HYDROGEN STORAGE
RAMAN SPECTROSCOPY
STABILITY
SYNCHROTRONS
X-RAY DIFFRACTION