MgCd crystallizes in the hexagonal P-6m2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent Mg(2), six equivalent Mg(1), and three equivalent Cd(2) atoms to form distorted MgMg9Cd3 cuboctahedra that share corners with six equivalent Cd(1)Cd12 cuboctahedra, corners with twelve equivalent Mg(1)Mg9Cd3 cuboctahedra, edges with six equivalent Mg(2)Mg12 cuboctahedra, edges with six equivalent Mg(1)Mg9Cd3 cuboctahedra, edges with six equivalent Cd(2)Mg3Cd9 cuboctahedra,  a faceface with one Cd(1)Cd12 cuboctahedra, faces with six equivalent Mg(2)Mg12 cuboctahedra, faces with six equivalent Cd(2)Mg3Cd9 cuboctahedra, and faces with seven equivalent Mg(1)Mg9Cd3 cuboctahedra. In the second Mg site, Mg(2) is bonded to six equivalent Mg(1) and six equivalent Mg(2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with twelve equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with six equivalent Mg(2)Mg12 cuboctahedra, edges with twelve equivalent Mg(1)Mg9Cd3 cuboctahedra, faces with two equivalent Cd(2)Mg3Cd9 cuboctahedra, faces with six equivalent Mg(2)Mg12 cuboctahedra, and faces with twelve equivalent Mg(1)Mg9Cd3 cuboctahedra. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to six equivalent Cd(1) and six equivalent Cd(2) atoms to form CdCd12 cuboctahedra that share corners with six equivalent Cd(1)Cd12 cuboctahedra, corners with twelve equivalent Mg(1)Mg9Cd3 cuboctahedra, edges with six equivalent Cd(1)Cd12 cuboctahedra, edges with twelve equivalent Cd(2)Mg3Cd9 cuboctahedra, faces with two equivalent Mg(1)Mg9Cd3 cuboctahedra, faces with six equivalent Cd(1)Cd12 cuboctahedra, and faces with twelve equivalent Cd(2)Mg3Cd9 cuboctahedra. In the second Cd site, Cd(2) is bonded to three equivalent Mg(1), three equivalent Cd(1), and six equivalent Cd(2) atoms to form distorted CdMg3Cd9 cuboctahedra that share corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with twelve equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with six equivalent Mg(1)Mg9Cd3 cuboctahedra, edges with six equivalent Cd(1)Cd12 cuboctahedra, edges with six equivalent Cd(2)Mg3Cd9 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with six equivalent Mg(1)Mg9Cd3 cuboctahedra, faces with six equivalent Cd(1)Cd12 cuboctahedra, and faces with seven equivalent Cd(2)Mg3Cd9 cuboctahedra.
MgCd crystallizes in the hexagonal P-6m2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent Mg(2), six equivalent Mg(1), and three equivalent Cd(2) atoms to form distorted MgMg9Cd3 cuboctahedra that share corners with six equivalent Cd(1)Cd12 cuboctahedra, corners with twelve equivalent Mg(1)Mg9Cd3 cuboctahedra, edges with six equivalent Mg(2)Mg12 cuboctahedra, edges with six equivalent Mg(1)Mg9Cd3 cuboctahedra, edges with six equivalent Cd(2)Mg3Cd9 cuboctahedra,  a faceface with one Cd(1)Cd12 cuboctahedra, faces with six equivalent Mg(2)Mg12 cuboctahedra, faces with six equivalent Cd(2)Mg3Cd9 cuboctahedra, and faces with seven equivalent Mg(1)Mg9Cd3 cuboctahedra. All Mg(1)-Mg(2) bond lengths are 3.25 Å. All Mg(1)-Mg(1) bond lengths are 3.12 Å. All Mg(1)-Cd(2) bond lengths are 3.20 Å. In the second Mg site, Mg(2) is bonded to six equivalent Mg(1) and six equivalent Mg(2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with twelve equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with six equivalent Mg(2)Mg12 cuboctahedra, edges with twelve equivalent Mg(1)Mg9Cd3 cuboctahedra, faces with two equivalent Cd(2)Mg3Cd9 cuboctahedra, faces with six equivalent Mg(2)Mg12 cuboctahedra, and faces with twelve equivalent Mg(1)Mg9Cd3 cuboctahedra. All Mg(2)-Mg(2) bond lengths are 3.12 Å. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to six equivalent Cd(1) and six equivalent Cd(2) atoms to form CdCd12 cuboctahedra that share corners with six equivalent Cd(1)Cd12 cuboctahedra, corners with twelve equivalent Mg(1)Mg9Cd3 cuboctahedra, edges with six equivalent Cd(1)Cd12 cuboctahedra, edges with twelve equivalent Cd(2)Mg3Cd9 cuboctahedra, faces with two equivalent Mg(1)Mg9Cd3 cuboctahedra, faces with six equivalent Cd(1)Cd12 cuboctahedra, and faces with twelve equivalent Cd(2)Mg3Cd9 cuboctahedra. All Cd(1)-Cd(1) bond lengths are 3.12 Å. All Cd(1)-Cd(2) bond lengths are 3.25 Å. In the second Cd site, Cd(2) is bonded to three equivalent Mg(1), three equivalent Cd(1), and six equivalent Cd(2) atoms to form distorted CdMg3Cd9 cuboctahedra that share corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with twelve equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with six equivalent Mg(1)Mg9Cd3 cuboctahedra, edges with six equivalent Cd(1)Cd12 cuboctahedra, edges with six equivalent Cd(2)Mg3Cd9 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with six equivalent Mg(1)Mg9Cd3 cuboctahedra, faces with six equivalent Cd(1)Cd12 cuboctahedra, and faces with seven equivalent Cd(2)Mg3Cd9 cuboctahedra. All Cd(2)-Cd(2) bond lengths are 3.12 Å.