Materials Data on Mg2Cu3Ge by Materials Project

Abstract

Mg2Cu3Ge is Hexagonal Laves-derived structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a 12-coordinate geometry to three equivalent Mg, eight Cu, and four equivalent Ge atoms. There are two shorter (3.09 Å) and one longer (3.10 Å) Mg–Mg bond lengths. There are a spread of Mg–Cu bond distances ranging from 2.78–3.07 Å. There are two shorter (3.02 Å) and two longer (3.05 Å) Mg–Ge bond lengths. In the second Mg site, Mg is bonded in a 12-coordinate geometry to four Mg, ten Cu, and two equivalent Ge atoms. The Mg–Mg bond length is 2.85 Å. There are a spread of Mg–Cu bond distances ranging from 2.90–3.03 Å. Both Mg–Ge bond lengths are 3.02 Å. There are four inequivalent Cu sites. In the first Cu site, Cu is bonded to six Mg, two equivalent Cu, and four equivalent Ge atoms to form CuMg6Cu2Ge4 cuboctahedra that share corners with eighteen CuMg6Cu2Ge4 cuboctahedra, edges with six CuMg6Cu2Ge4 cuboctahedra, faces with eight equivalent GeMg6Cu4Ge2 cuboctahedra, and faces with ten CuMg6Cu6 cuboctahedra. Both Cu–Cu bond lengths are 2.54 Å. There are two shorter (2.49 Å) and two longer (2.58 Å) Cu–Ge bond lengths. In the second Cu site, Cu is bonded to six Mg and six Cu atoms to form CuMg6Cu6 cuboctahedra that share corners with six equivalent GeMg6Cu4Ge2 cuboctahedra, corners with twelve CuMg6Cu2Ge4 cuboctahedra, edges with two equivalent CuMg6Cu6 cuboctahedra, edges with four equivalent GeMg6Cu4Ge2 cuboctahedra, faces with two equivalent GeMg6Cu4Ge2 cuboctahedra, and faces with sixteen CuMg6Cu2Ge4 cuboctahedra. There are a spread of Cu–Cu bond distances ranging from 2.50–2.61 Å. In the third Cu site, Cu is bonded to six Mg and six Cu atoms to form CuMg6Cu6 cuboctahedra that share corners with eight equivalent GeMg6Cu4Ge2 cuboctahedra, corners with ten CuMg6Cu2Ge4 cuboctahedra, edges with six CuMg6Cu2Ge4 cuboctahedra, faces with four equivalent GeMg6Cu4Ge2 cuboctahedra, and faces with fourteen CuMg6Cu6 cuboctahedra. Both Cu–Cu bond lengths are 2.51 Å. In the fourth Cu site, Cu is bonded to six Mg, four Cu, and two equivalent Ge atoms to form CuMg6Cu4Ge2 cuboctahedra that share corners with four equivalent GeMg6Cu4Ge2 cuboctahedra, corners with eight CuMg6Cu2Ge4 cuboctahedra, edges with six equivalent CuMg6Cu4Ge2 cuboctahedra, faces with six equivalent GeMg6Cu4Ge2 cuboctahedra, and faces with fourteen CuMg6Cu2Ge4 cuboctahedra. Both Cu–Ge bond lengths are 2.52 Å. Ge is bonded to six Mg, four Cu, and two equivalent Ge atoms to form distorted GeMg6Cu4Ge2 cuboctahedra that share corners with four equivalent GeMg6Cu4Ge2 cuboctahedra, corners with fourteen CuMg6Cu6 cuboctahedra, edges with two equivalent GeMg6Cu4Ge2 cuboctahedra, edges with four equivalent CuMg6Cu6 cuboctahedra, faces with four equivalent GeMg6Cu4Ge2 cuboctahedra, and faces with fourteen CuMg6Cu2Ge4 cuboctahedra. There are one shorter (2.55 Å) and one longer (2.59 Å) Ge–Ge bond lengths.