Structural Phase Transitions of Mg(BH[subscript 4])[subscript 2] under Pressure
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 Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1005448
- Journal Information:
- J. Phys. Chem. C, Vol. 113, Issue (1) ; 2009; ISSN 1932-7447
- Country of Publication:
- United States
- Language:
- ENGLISH
Similar Records
Synthesis and equation of state of post-perovskites in the (Mg,Fe)[subscript 3]Al[subscript 2]Si[subscript 3]O[subscript 12] system
Effect of pressure and composition on lattice parameters and unit-cell volume of (Fe,Mg)SiO[subscript 3] post-perovskite