Materials Data on Sm6Mg23C by Materials Project

Abstract

Mg23Sm6C crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a 1-coordinate geometry to ten Mg and three equivalent Sm atoms. There are a spread of Mg–Mg bond distances ranging from 2.98–3.44 Å. All Mg–Sm bond lengths are 3.71 Å. In the second Mg site, Mg is bonded to eight Mg and four equivalent Sm atoms to form MgSm4Mg8 cuboctahedra that share corners with twelve MgSm4Mg8 cuboctahedra, edges with two equivalent CSm6 octahedra, and faces with sixteen MgSm4Mg8 cuboctahedra. All Mg–Mg bond lengths are 2.92 Å. All Mg–Sm bond lengths are 3.70 Å. In the third Mg site, Mg is bonded in a body-centered cubic geometry to eight equivalent Mg atoms. In the fourth Mg site, Mg is bonded to nine Mg and three equivalent Sm atoms to form MgSm3Mg9 cuboctahedra that share corners with twelve MgSm4Mg8 cuboctahedra, faces with twelve MgSm4Mg8 cuboctahedra, and a faceface with one CSm6 octahedra. All Mg–Mg bond lengths are 3.23 Å. All Mg–Sm bond lengths are 3.44 Å. Sm is bonded in a single-bond geometry to twelve Mg and one C atom. The Sm–C bond length is 2.61 Å. C is bonded to six equivalent Sm atoms to form CSm6 octahedra that share edges with twelve equivalent MgSm4Mg8 cuboctahedra and faces with eight equivalent MgSm3Mg9 cuboctahedra.