Materials Data on MgCd2 by Materials Project

Abstract

MgCd2 is beta-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded to six equivalent Mg and six Cd atoms to form MgMg6Cd6 cuboctahedra that share corners with six equivalent CdCd12 cuboctahedra, corners with twelve MgMg6Cd6 cuboctahedra, edges with six equivalent MgMg6Cd6 cuboctahedra, edges with twelve CdMg3Cd9 cuboctahedra, faces with seven MgMg6Cd6 cuboctahedra, and faces with thirteen CdCd12 cuboctahedra. All Mg–Mg bond lengths are 3.12 Å. There are three shorter (3.19 Å) and three longer (3.21 Å) Mg–Cd bond lengths. In the second Mg site, Mg is bonded to six equivalent Mg and six Cd atoms to form MgMg6Cd6 cuboctahedra that share corners with six equivalent CdCd12 cuboctahedra, corners with twelve MgMg6Cd6 cuboctahedra, edges with six equivalent MgMg6Cd6 cuboctahedra, edges with twelve CdMg3Cd9 cuboctahedra, faces with seven MgMg6Cd6 cuboctahedra, and faces with thirteen CdCd12 cuboctahedra. All Mg–Mg bond lengths are 3.12 Å. There are three shorter (3.19 Å) and three longer (3.21 Å) Mg–Cd bond lengths. There are three inequivalent Cd sites. In the first Cd site, Cd is bonded to twelve Cd atoms to form CdCd12 cuboctahedra that share corners with six equivalent CdCd12 cuboctahedra, corners with twelve MgMg6Cd6 cuboctahedra, edges with eighteen CdCd12 cuboctahedra, faces with two MgMg6Cd6 cuboctahedra, and faces with eighteen CdCd12 cuboctahedra. There are six shorter (3.12 Å) and six longer (3.25 Å) Cd–Cd bond lengths. In the second Cd site, Cd is bonded to three equivalent Mg and nine Cd atoms to form distorted CdMg3Cd9 cuboctahedra that share corners with eighteen CdMg3Cd9 cuboctahedra, edges with six equivalent MgMg6Cd6 cuboctahedra, edges with twelve CdCd12 cuboctahedra, faces with six equivalent MgMg6Cd6 cuboctahedra, and faces with fourteen CdCd12 cuboctahedra. All Cd–Cd bond lengths are 3.12 Å. In the third Cd site, Cd is bonded to six Mg and six equivalent Cd atoms to form CdMg6Cd6 cuboctahedra that share corners with eighteen CdMg3Cd9 cuboctahedra, edges with six equivalent CdMg6Cd6 cuboctahedra, edges with twelve MgMg6Cd6 cuboctahedra, faces with eight CdMg3Cd9 cuboctahedra, and faces with twelve MgMg6Cd6 cuboctahedra. All Cd–Cd bond lengths are 3.12 Å.