The energy landscape of Mg(BH4)2 under pressure is explored by ab initio evolutionary calculations. Two new tetragonal structures, with space groups P-4 and I41/acd are predicted to be lower in enthalpy, by 15.4 kJ/mol and 21.2 kJ/mol, respectively, than the earlier proposed P42nm phase. We have simulated X-ray diffraction (XRD) spectra, lattice dynamics, and equations of state (EOS) of these phases. The density, volume contraction, bulk modulus, and the simulated XRD patterns of I41/acd and P-4 structures are in excellent agreement with the experimental results.
@article{arxiv.1211.6948,
title = {First-Principles Determination of the Structure of Magnesium Borohydride},
author = {Xiang-Feng Zhou and Artem R. Oganov and Guang-Rui Qian and Qiang Zhu},
journal= {arXiv preprint arXiv:1211.6948},
year = {2012}
}