Syntheses of Novel Hydrides Containing Light Elements under High Pressure and High Temperature

Abstract

This paper describes high-pressure synthetic studies on novel hydrides. High-pressure hydrogenation experiments are carried out using a cubic-type multi-anvil apparatus. In-situ synchrotron radiation X-ray diffraction measurements are effectively used to explore synthetic conditions, to investigate the reaction mechanisms, and to characterize the thermodynamic stabilities of the obtained hydrides. Theoretical calculations based on first-principles calculations enable us to predict the thermal stability and crystal structure of the target hydrides before the high-pressure experiments, which leads to the rapid discovery of the novel hydrides. Lithium-containing hydrides, YLiFeH 6 , LiNiH 3 , Li 4 FeH 6 , and Li 3 AlFeH 8 are synthesized. Syntheses of aluminum-based alloys hydrides, Al 2 CuH and Al 3 FeH 4 under high-pressure are also described. These results demonstrate that the high-pressure technique is useful for discovering novel hydrides.