Mg3Sb is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Mg(1) is bonded to eight equivalent Mg(1) and four equivalent Sb(1) atoms to form distorted MgMg8Sb4 cuboctahedra that share corners with four equivalent Sb(1)Mg12 cuboctahedra, corners with fourteen equivalent Mg(1)Mg8Sb4 cuboctahedra, edges with six equivalent Sb(1)Mg12 cuboctahedra, edges with twelve equivalent Mg(1)Mg8Sb4 cuboctahedra, faces with four equivalent Sb(1)Mg12 cuboctahedra, and faces with sixteen equivalent Mg(1)Mg8Sb4 cuboctahedra. Sb(1) is bonded to twelve equivalent Mg(1) atoms to form SbMg12 cuboctahedra that share corners with six equivalent Sb(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(1)Mg8Sb4 cuboctahedra, edges with eighteen equivalent Mg(1)Mg8Sb4 cuboctahedra, faces with eight equivalent Sb(1)Mg12 cuboctahedra, and faces with twelve equivalent Mg(1)Mg8Sb4 cuboctahedra.
Mg3Sb is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Mg(1) is bonded to eight equivalent Mg(1) and four equivalent Sb(1) atoms to form distorted MgMg8Sb4 cuboctahedra that share corners with four equivalent Sb(1)Mg12 cuboctahedra, corners with fourteen equivalent Mg(1)Mg8Sb4 cuboctahedra, edges with six equivalent Sb(1)Mg12 cuboctahedra, edges with twelve equivalent Mg(1)Mg8Sb4 cuboctahedra, faces with four equivalent Sb(1)Mg12 cuboctahedra, and faces with sixteen equivalent Mg(1)Mg8Sb4 cuboctahedra. There are a spread of Mg(1)-Mg(1) bond distances ranging from 3.09-3.25 Å. There are two shorter (3.13 Å) and two longer (3.28 Å) Mg(1)-Sb(1) bond lengths. Sb(1) is bonded to twelve equivalent Mg(1) atoms to form SbMg12 cuboctahedra that share corners with six equivalent Sb(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(1)Mg8Sb4 cuboctahedra, edges with eighteen equivalent Mg(1)Mg8Sb4 cuboctahedra, faces with eight equivalent Sb(1)Mg12 cuboctahedra, and faces with twelve equivalent Mg(1)Mg8Sb4 cuboctahedra.