Novel hydrides in Li-TM systems synthesized by high pressure method (TM = Ti, Zr, Hf)

New Li-based hydrides have been prepared under GPa-order by using a cubic-anvil-type apparatus. Novel compounds in Li-Zr and Li-Hf systems were obtained at 973 K under 5 GPa. For Li-Zr system, a novel compound has a primitive cubic structure with a = 0.42188(3) nm. The compound was thermally stable up to 723 K under Ar flow. For Li-Hf system, two novel compounds were successfully synthesized. Crystal structures of these compounds were found to be a primitive cubic (a = 0.4209(2) nm) and a body centered cubic (a = 1.08369(4) nm). A structural model of the new compounds with the body-centered cubic structure was found to be an Ag₈Ca₃-type structure. The novel compound with a primitive cubic structure was thermally stable up to 723 K, but the compound with the body centered cubic structure was decomposed at 600 K with an endothermic reaction.