Elastic properties and electronic structures of MgCe intermetallic compounds from first‐principles calculations

Abstract

First-principles calculations have been carried out to investigate the elastic properties and electronic structures of the main binary Mg-Ce phases MgCe, Mg 2 Ce, and Mg 3 Ce. The optimized equilibrium lattice constants are in agreement with the available experimental values, and the structural stability of MgCe, Mg 2 Ce, and Mg 3 Ce is studied from the calculated heat of formation and cohesive energy. The elastic constants C ij of these phases are calculated; then the bulk modulus, shear modulus, Young's modulus, Cauchy pressure, and the ratio of bulk to shear modulus B/G are further investigated. The obtained results indicate that Mg 2 Ce has the best ductility and plasticity, while Mg 3 Ce is the hardest and the most brittle among the three Mg-Ce phases. The density of states (DOSs) and charge density distribution of the Mg-Ce phases are also calculated to reveal the underlying mechanism for the structural stability and elastic properties of these Mg-Ce phases.

Crystal, Magnetic Structures, and Bonding Interactions in the TiNiSi-Type Hydride CeMgSnH: Experimental and Computational Studies

“…The hydrogen (deuterium) distribution consists of four symmetry-independent, fully occupied sites having triangular Ce 2 Mg and tetrahedral Ce 2 Mg 2 and Mg 4 metal coordinations with distances in the ranges of Ce–D = 2.36–2.51 Å and Mg–D = 1.91–2.18 Å. Interestingly, CeMg 2 does not disproportionate into MgH 2 and CeH 3 even when subjected to the H 2 pressure of 50 bar H 2 at 100 °C and instead forms CeMg 2 H 7 . This can be related to the bonding interactions between Ce and Mg atoms which were theoretically studied in ref which prevents such a disproportionation.…”