Several new studies of Mg(BH4)2 are reported. A 1:1 LiBH4:Mg(BH4)2 mixture was studied by in situ synchrotron X-ray diffraction and reveals an eutectic behavior with the eutectic composition more rich in Mg(BH4)2, and the eutectic temperature lower than 456 K. No dual cation compound was observed in this experiment.

New vibrational spectra including INS data have been obtained and are compared with theoretical DFT calculations and recent NMR studies, showing good agreement.

Deuterium−hydrogen exchange in solid α-Mg(BH4)2 is demonstrated. Compared to the previously reported exchange reactions in the alkali borohydrides, the temperature at which isotope exchange starts to take place is significantly lower (132 °C vs 200 °C for LiBH4). The activation energy for the deuterium−hydrogen exchange reaction is estimated to be 51 ± 15 kJ/mol. Almost complete isotope exchange was observed by treating solid Mg(BH4)2 for 72 h at 172 °C with 42 bar of D2. Preliminary experiments indicate that under these conditions Ca(BH4)2 also undergoes isotope exchange.

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Last update Friday March 02 2018