Synthesis of new hydrides in Mg-Y systems by using high pressure

A new hydride in the MgH2-YH3 system was found by using a high pressure of 5 GPa, and their crystal structure, thermal stability and hydrogen content were studied. The high-pressure synthesis was carried out at 1073 K for 2 h under 5 GPa by using an anvil-type apparatus. In the MgH2-xat%YH3 system (x = 33-100), novel hydride was synthesized near x = 67 (MgY2Hy). This phase exhibited a FCC-type structure with a cell parameter of a = 0.516 nm. This high-pressure phase was dehydrogenated at about 600 K under an At atmosphere of 0.05 MPa, and the FCC structure was maintained after dehydrogenation. The amount of hydrogen desorbed at about 600 K was 1.4 mass%.