High-pressure synthesis of a novel compound in Mg–Y system

Abstract

This study involved the investigation of a novel compound in the Mg–Y system using a high-pressure synthesis technique. The crystal structure, thermal stability, and hydrogenation properties of the newly found compound were comprehensively evaluated. Mg3Y exhibiting a face-centered cubic structure was prepared at a pressure in the order of GPa. From X-ray diffraction analysis, the lattice parameter was determined to be a = 7.29939(4) Å. Following an endothermic reaction at approximately 588 K under an Ar atmosphere, Mg3Y was found to decompose into Mg24Y5 and Mg2Y phases. Hydrogenation of Mg3Y at 473 K under 8 MPa of H2 for 72 h resulted in decomposition into ambient-pressure and high-pressure phases of both MgH2 and YH3. The hydrogen content of hydrogenated Mg3Y was established to be 3.52 mass%. Hydrogenation reactions at high pressure (in the order of GPa) were also conducted for Mg3Y and Mg3La, which display analogous crystal structures. A Mg3La hydride was obtained as a tetragonal structure at a pressure of more than 2 GPa, whereas formation of a Mg3Y hydride was not observed.