MgCd5 crystallizes in the hexagonal P-62m space group. Mg(1) is bonded to six equivalent Cd(1) and six equivalent Cd(2) atoms to form MgCd12 cuboctahedra that share corners with eighteen equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with six equivalent Mg(1)Cd12 cuboctahedra, edges with twelve equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Mg(1)Cd12 cuboctahedra, faces with six equivalent Cd(2)Mg3Cd9 cuboctahedra, and faces with twelve equivalent Cd(1)Mg2Cd10 cuboctahedra. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent Mg(1), four equivalent Cd(2), and six equivalent Cd(1) atoms to form CdMg2Cd10 cuboctahedra that share corners with eighteen equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with four equivalent Mg(1)Cd12 cuboctahedra, edges with six equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with eight equivalent Cd(2)Mg3Cd9 cuboctahedra, faces with four equivalent Mg(1)Cd12 cuboctahedra, faces with eight equivalent Cd(1)Mg2Cd10 cuboctahedra, and faces with eight equivalent Cd(2)Mg3Cd9 cuboctahedra. In the second Cd site, Cd(2) is bonded to three equivalent Mg(1), three equivalent Cd(2), and six equivalent Cd(1) atoms to form distorted CdMg3Cd9 cuboctahedra that share corners with nine equivalent Mg(1)Cd12 cuboctahedra, corners with nine equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with six equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with twelve equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with three equivalent Mg(1)Cd12 cuboctahedra, faces with five equivalent Cd(2)Mg3Cd9 cuboctahedra, and faces with twelve equivalent Cd(1)Mg2Cd10 cuboctahedra.
MgCd5 crystallizes in the hexagonal P-62m space group. Mg(1) is bonded to six equivalent Cd(1) and six equivalent Cd(2) atoms to form MgCd12 cuboctahedra that share corners with eighteen equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with six equivalent Mg(1)Cd12 cuboctahedra, edges with twelve equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with two equivalent Mg(1)Cd12 cuboctahedra, faces with six equivalent Cd(2)Mg3Cd9 cuboctahedra, and faces with twelve equivalent Cd(1)Mg2Cd10 cuboctahedra. All Mg(1)-Cd(1) bond lengths are 3.27 Å. All Mg(1)-Cd(2) bond lengths are 2.99 Å. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent Mg(1), four equivalent Cd(2), and six equivalent Cd(1) atoms to form CdMg2Cd10 cuboctahedra that share corners with eighteen equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with four equivalent Mg(1)Cd12 cuboctahedra, edges with six equivalent Cd(1)Mg2Cd10 cuboctahedra, edges with eight equivalent Cd(2)Mg3Cd9 cuboctahedra, faces with four equivalent Mg(1)Cd12 cuboctahedra, faces with eight equivalent Cd(1)Mg2Cd10 cuboctahedra, and faces with eight equivalent Cd(2)Mg3Cd9 cuboctahedra. All Cd(1)-Cd(2) bond lengths are 3.28 Å. There are two shorter (2.98 Å) and four longer (3.00 Å) Cd(1)-Cd(1) bond lengths. In the second Cd site, Cd(2) is bonded to three equivalent Mg(1), three equivalent Cd(2), and six equivalent Cd(1) atoms to form distorted CdMg3Cd9 cuboctahedra that share corners with nine equivalent Mg(1)Cd12 cuboctahedra, corners with nine equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with six equivalent Cd(2)Mg3Cd9 cuboctahedra, edges with twelve equivalent Cd(1)Mg2Cd10 cuboctahedra, faces with three equivalent Mg(1)Cd12 cuboctahedra, faces with five equivalent Cd(2)Mg3Cd9 cuboctahedra, and faces with twelve equivalent Cd(1)Mg2Cd10 cuboctahedra. All Cd(2)-Cd(2) bond lengths are 2.99 Å.