High pressure synthesis of novel metal hydrides

Among metal hydrides, magnesium hydride (MgH₂) would be a promising candidate for hydrogen storage materials because of its high hydrogen-storage capacity 7.6 mass%. However, the dehydrogenation temperature is too high for wide practical applications. Novel magnesium-based hydrides with better dehydrogenation properties than MgH₂ can be prepared under hydrogen pressure of gigapascal (GPa). For instance, Mg₇TiH ₁₆ 6.9 mass% would release hydrogen at a lower temperature by 130 K than MgH₂. The Mg-H ionic bonding distance in Mg₇TiH ₁₆ is longer than that in MgH₂. The observed lower dehydrogenation temperature seems to be consistent with the structure.