MgCd crystallizes in the monoclinic Cm space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(3), three equivalent Mg(2), one Cd(2), two equivalent Cd(1), and two equivalent Cd(3) atoms to form distorted MgMg7Cd5 cuboctahedra that share corners with six equivalent Mg(3)Mg6Cd6 cuboctahedra, corners with six equivalent Mg(1)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with two equivalent Mg(2)Mg7Cd5 cuboctahedra, edges with three equivalent Mg(3)Mg6Cd6 cuboctahedra, edges with three equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with four equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with six equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with two equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with three equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with three equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with three equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra, and faces with five equivalent Mg(2)Mg7Cd5 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(2), two equivalent Mg(3), three equivalent Mg(1), one Cd(3), two equivalent Cd(1), and two equivalent Cd(2) atoms to form distorted MgMg7Cd5 cuboctahedra that share corners with six equivalent Mg(2)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(1)Mg5Cd7 cuboctahedra, corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with two equivalent Mg(1)Mg7Cd5 cuboctahedra, edges with three equivalent Cd(1)Mg5Cd7 cuboctahedra, edges with three equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with four equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with six equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with two equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with three equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with three equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with three equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with four equivalent Cd(3)Mg5Cd7 cuboctahedra, and faces with five equivalent Mg(1)Mg7Cd5 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), one Cd(1), two equivalent Cd(3), and three equivalent Cd(2) atoms to form distorted MgMg6Cd6 cuboctahedra that share corners with six equivalent Mg(3)Mg6Cd6 cuboctahedra, corners with six equivalent Mg(1)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with two equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with three equivalent Mg(1)Mg7Cd5 cuboctahedra, edges with three equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with four equivalent Cd(1)Mg5Cd7 cuboctahedra, edges with six equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with two equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with three equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with three equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with three equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with four equivalent Cd(1)Mg5Cd7 cuboctahedra, and faces with five equivalent Cd(2)Mg6Cd6 cuboctahedra. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one Mg(3), two equivalent Mg(1), two equivalent Mg(2), two equivalent Cd(1), two equivalent Cd(2), and three equivalent Cd(3) atoms to form distorted CdMg5Cd7 cuboctahedra that share corners with six equivalent Mg(2)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(1)Mg5Cd7 cuboctahedra, corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with two equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with three equivalent Mg(2)Mg7Cd5 cuboctahedra, edges with three equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with four equivalent Mg(3)Mg6Cd6 cuboctahedra, edges with six equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with two equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with three equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with three equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with three equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with four equivalent Mg(3)Mg6Cd6 cuboctahedra, and faces with five equivalent Cd(3)Mg5Cd7 cuboctahedra. In the second Cd site, Cd(2) is bonded to one Mg(1), two equivalent Mg(2), three equivalent Mg(3), two equivalent Cd(1), two equivalent Cd(2), and two equivalent Cd(3) atoms to form distorted CdMg6Cd6 cuboctahedra that share corners with six equivalent Mg(2)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(1)Mg5Cd7 cuboctahedra, corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with two equivalent Mg(3)Mg6Cd6 cuboctahedra, edges with three equivalent Mg(2)Mg7Cd5 cuboctahedra, edges with three equivalent Cd(1)Mg5Cd7 cuboctahedra, edges with four equivalent Mg(1)Mg7Cd5 cuboctahedra, edges with six equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with two equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with three equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with three equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with three equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with four equivalent Mg(1)Mg7Cd5 cuboctahedra, and faces with five equivalent Mg(3)Mg6Cd6 cuboctahedra. In the third Cd site, Cd(3) is bonded to one Mg(2), two equivalent Mg(1), two equivalent Mg(3), two equivalent Cd(2), two equivalent Cd(3), and three equivalent Cd(1) atoms to form distorted CdMg5Cd7 cuboctahedra that share corners with six equivalent Mg(3)Mg6Cd6 cuboctahedra, corners with six equivalent Mg(1)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with two equivalent Cd(1)Mg5Cd7 cuboctahedra, edges with three equivalent Mg(3)Mg6Cd6 cuboctahedra, edges with three equivalent Mg(1)Mg7Cd5 cuboctahedra, edges with four equivalent Mg(2)Mg7Cd5 cuboctahedra, edges with six equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with two equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with three equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with three equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with three equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with four equivalent Mg(2)Mg7Cd5 cuboctahedra, and faces with five equivalent Cd(1)Mg5Cd7 cuboctahedra.
MgCd crystallizes in the monoclinic Cm space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(3), three equivalent Mg(2), one Cd(2), two equivalent Cd(1), and two equivalent Cd(3) atoms to form distorted MgMg7Cd5 cuboctahedra that share corners with six equivalent Mg(3)Mg6Cd6 cuboctahedra, corners with six equivalent Mg(1)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with two equivalent Mg(2)Mg7Cd5 cuboctahedra, edges with three equivalent Mg(3)Mg6Cd6 cuboctahedra, edges with three equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with four equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with six equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with two equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with three equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with three equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with three equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra, and faces with five equivalent Mg(2)Mg7Cd5 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 3.10 Å. Both Mg(1)-Mg(3) bond lengths are 3.16 Å. There is one shorter (3.13 Å) and two longer (3.21 Å) Mg(1)-Mg(2) bond lengths. The Mg(1)-Cd(2) bond length is 3.06 Å. Both Mg(1)-Cd(1) bond lengths are 3.08 Å. Both Mg(1)-Cd(3) bond lengths are 3.03 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(2), two equivalent Mg(3), three equivalent Mg(1), one Cd(3), two equivalent Cd(1), and two equivalent Cd(2) atoms to form distorted MgMg7Cd5 cuboctahedra that share corners with six equivalent Mg(2)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(1)Mg5Cd7 cuboctahedra, corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with two equivalent Mg(1)Mg7Cd5 cuboctahedra, edges with three equivalent Cd(1)Mg5Cd7 cuboctahedra, edges with three equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with four equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with six equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with two equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with three equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with three equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with three equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with four equivalent Cd(3)Mg5Cd7 cuboctahedra, and faces with five equivalent Mg(1)Mg7Cd5 cuboctahedra. Both Mg(2)-Mg(2) bond lengths are 3.10 Å. Both Mg(2)-Mg(3) bond lengths are 3.17 Å. The Mg(2)-Cd(3) bond length is 3.07 Å. Both Mg(2)-Cd(1) bond lengths are 3.08 Å. Both Mg(2)-Cd(2) bond lengths are 3.04 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), one Cd(1), two equivalent Cd(3), and three equivalent Cd(2) atoms to form distorted MgMg6Cd6 cuboctahedra that share corners with six equivalent Mg(3)Mg6Cd6 cuboctahedra, corners with six equivalent Mg(1)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with two equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with three equivalent Mg(1)Mg7Cd5 cuboctahedra, edges with three equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with four equivalent Cd(1)Mg5Cd7 cuboctahedra, edges with six equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with two equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with three equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with three equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with three equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with four equivalent Cd(1)Mg5Cd7 cuboctahedra, and faces with five equivalent Cd(2)Mg6Cd6 cuboctahedra. Both Mg(3)-Mg(3) bond lengths are 3.10 Å. The Mg(3)-Cd(1) bond length is 3.05 Å. Both Mg(3)-Cd(3) bond lengths are 3.06 Å. There are two shorter (3.15 Å) and one longer (3.17 Å) Mg(3)-Cd(2) bond length. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one Mg(3), two equivalent Mg(1), two equivalent Mg(2), two equivalent Cd(1), two equivalent Cd(2), and three equivalent Cd(3) atoms to form distorted CdMg5Cd7 cuboctahedra that share corners with six equivalent Mg(2)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(1)Mg5Cd7 cuboctahedra, corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with two equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with three equivalent Mg(2)Mg7Cd5 cuboctahedra, edges with three equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with four equivalent Mg(3)Mg6Cd6 cuboctahedra, edges with six equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with two equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with three equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with three equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with three equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with four equivalent Mg(3)Mg6Cd6 cuboctahedra, and faces with five equivalent Cd(3)Mg5Cd7 cuboctahedra. Both Cd(1)-Cd(1) bond lengths are 3.10 Å. Both Cd(1)-Cd(2) bond lengths are 3.12 Å. There is one shorter (3.13 Å) and two longer (3.20 Å) Cd(1)-Cd(3) bond lengths. In the second Cd site, Cd(2) is bonded to one Mg(1), two equivalent Mg(2), three equivalent Mg(3), two equivalent Cd(1), two equivalent Cd(2), and two equivalent Cd(3) atoms to form distorted CdMg6Cd6 cuboctahedra that share corners with six equivalent Mg(2)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(1)Mg5Cd7 cuboctahedra, corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with two equivalent Mg(3)Mg6Cd6 cuboctahedra, edges with three equivalent Mg(2)Mg7Cd5 cuboctahedra, edges with three equivalent Cd(1)Mg5Cd7 cuboctahedra, edges with four equivalent Mg(1)Mg7Cd5 cuboctahedra, edges with six equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with two equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with three equivalent Mg(2)Mg7Cd5 cuboctahedra, faces with three equivalent Cd(1)Mg5Cd7 cuboctahedra, faces with three equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with four equivalent Mg(1)Mg7Cd5 cuboctahedra, and faces with five equivalent Mg(3)Mg6Cd6 cuboctahedra. Both Cd(2)-Cd(2) bond lengths are 3.10 Å. Both Cd(2)-Cd(3) bond lengths are 3.22 Å. In the third Cd site, Cd(3) is bonded to one Mg(2), two equivalent Mg(1), two equivalent Mg(3), two equivalent Cd(2), two equivalent Cd(3), and three equivalent Cd(1) atoms to form distorted CdMg5Cd7 cuboctahedra that share corners with six equivalent Mg(3)Mg6Cd6 cuboctahedra, corners with six equivalent Mg(1)Mg7Cd5 cuboctahedra, corners with six equivalent Cd(3)Mg5Cd7 cuboctahedra, edges with two equivalent Cd(1)Mg5Cd7 cuboctahedra, edges with three equivalent Mg(3)Mg6Cd6 cuboctahedra, edges with three equivalent Mg(1)Mg7Cd5 cuboctahedra, edges with four equivalent Mg(2)Mg7Cd5 cuboctahedra, edges with six equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with two equivalent Cd(3)Mg5Cd7 cuboctahedra, faces with three equivalent Mg(3)Mg6Cd6 cuboctahedra, faces with three equivalent Mg(1)Mg7Cd5 cuboctahedra, faces with three equivalent Cd(2)Mg6Cd6 cuboctahedra, faces with four equivalent Mg(2)Mg7Cd5 cuboctahedra, and faces with five equivalent Cd(1)Mg5Cd7 cuboctahedra. Both Cd(3)-Cd(3) bond lengths are 3.10 Å.