Materials Data on MgAg4 by Materials Project
MgAg4 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Mg is bonded to six equivalent Ag atoms to form distorted MgAg6 cuboctahedra that share corners with six equivalent AgAg12 cuboctahedra, edges with six equivalent MgAg6 cuboctahedra, and edges with six equivalent AgAg12 cuboctahedra. All Mg–Ag bond lengths are 2.89 Å. There are two inequivalent Ag sites. In the first Ag site, Ag is bonded to three equivalent Mg and three equivalent Ag atoms to form a mixture of distorted corner and edge-sharing AgMg3Ag3 cuboctahedra. All Ag–Ag bond lengths are 2.93 Å. In the second Ag site, Ag is bonded to twelve Ag atoms to form AgAg12 cuboctahedra that share corners with three equivalent MgAg6 cuboctahedra, corners with fifteen AgMg3Ag3 cuboctahedra, edges with three equivalent MgAg6 cuboctahedra, edges with twenty-one AgMg3Ag3 cuboctahedra, and faces with twelve equivalent AgAg12 cuboctahedra. There are three shorter (2.90 Å) and six longer (3.02 Å) Ag–Ag bond lengths.