Mg6CdSb crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cd(1), and two equivalent Sb(1) atoms to form distorted MgMg6Cd2Sb2 cuboctahedra that share corners with two equivalent Mg(3)Mg10Cd2 cuboctahedra, corners with two equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with six equivalent Cd(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Mg10Cd2 cuboctahedra, corners with eight equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Cd2 cuboctahedra, edges with two equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cd(1), and two equivalent Sb(1) atoms to form distorted MgMg8Cd2Sb2 cuboctahedra that share corners with four equivalent Mg(3)Mg10Cd2 cuboctahedra, corners with four equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with ten equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Cd2 cuboctahedra, edges with two equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with four equivalent Cd(1)Mg10Sb2 cuboctahedra, edges with four equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with eight equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Cd(1) atoms to form distorted MgMg10Cd2 cuboctahedra that share corners with four equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, corners with six equivalent Mg(3)Mg10Cd2 cuboctahedra, corners with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with four equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with six equivalent Sb(1)Mg10Cd2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form distorted MgMg10Sb2 cuboctahedra that share corners with four equivalent Mg(3)Mg10Cd2 cuboctahedra, corners with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, corners with six equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Cd2 cuboctahedra, edges with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with four equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with six equivalent Cd(1)Mg10Sb2 cuboctahedra. Cd(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form CdMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)Mg10Cd2 cuboctahedra, corners with six equivalent Cd(1)Mg10Sb2 cuboctahedra, corners with twelve equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Cd2 cuboctahedra, edges with four equivalent Mg(3)Mg10Cd2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with six equivalent Mg(4)Mg10Sb2 cuboctahedra. Sb(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Cd(1) atoms to form SbMg10Cd2 cuboctahedra that share corners with four equivalent Cd(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Mg10Cd2 cuboctahedra, corners with twelve equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with two equivalent Cd(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with six equivalent Mg(3)Mg10Cd2 cuboctahedra.
Mg6CdSb crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cd(1), and two equivalent Sb(1) atoms to form distorted MgMg6Cd2Sb2 cuboctahedra that share corners with two equivalent Mg(3)Mg10Cd2 cuboctahedra, corners with two equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with six equivalent Cd(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Mg10Cd2 cuboctahedra, corners with eight equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Cd2 cuboctahedra, edges with two equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.21 Å. Both Mg(1)-Mg(3) bond lengths are 3.24 Å. Both Mg(1)-Mg(4) bond lengths are 3.24 Å. There is one shorter (3.13 Å) and one longer (3.15 Å) Mg(1)-Cd(1) bond length. Both Mg(1)-Sb(1) bond lengths are 3.14 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cd(1), and two equivalent Sb(1) atoms to form distorted MgMg8Cd2Sb2 cuboctahedra that share corners with four equivalent Mg(3)Mg10Cd2 cuboctahedra, corners with four equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with ten equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Cd2 cuboctahedra, edges with two equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with four equivalent Cd(1)Mg10Sb2 cuboctahedra, edges with four equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with eight equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra. There is one shorter (3.22 Å) and one longer (3.26 Å) Mg(2)-Mg(2) bond length. There is one shorter (3.14 Å) and one longer (3.15 Å) Mg(2)-Mg(3) bond length. There is one shorter (3.13 Å) and one longer (3.15 Å) Mg(2)-Mg(4) bond length. Both Mg(2)-Cd(1) bond lengths are 3.23 Å. Both Mg(2)-Sb(1) bond lengths are 3.24 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Cd(1) atoms to form distorted MgMg10Cd2 cuboctahedra that share corners with four equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, corners with six equivalent Mg(3)Mg10Cd2 cuboctahedra, corners with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with four equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with six equivalent Sb(1)Mg10Cd2 cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.24 Å. Both Mg(3)-Cd(1) bond lengths are 3.20 Å. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form distorted MgMg10Sb2 cuboctahedra that share corners with four equivalent Mg(3)Mg10Cd2 cuboctahedra, corners with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, corners with six equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Cd2 cuboctahedra, edges with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, edges with four equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with six equivalent Cd(1)Mg10Sb2 cuboctahedra. Both Mg(4)-Sb(1) bond lengths are 3.21 Å. Cd(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form CdMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)Mg10Cd2 cuboctahedra, corners with six equivalent Cd(1)Mg10Sb2 cuboctahedra, corners with twelve equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Cd2 cuboctahedra, edges with four equivalent Mg(3)Mg10Cd2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Cd2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with six equivalent Mg(4)Mg10Sb2 cuboctahedra. Both Cd(1)-Sb(1) bond lengths are 3.24 Å. Sb(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Cd(1) atoms to form SbMg10Cd2 cuboctahedra that share corners with four equivalent Cd(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Mg10Cd2 cuboctahedra, corners with twelve equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, edges with two equivalent Cd(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Cd(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Cd2 cuboctahedra, faces with four equivalent Mg(1)Mg6Cd2Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Cd2Sb2 cuboctahedra, and faces with six equivalent Mg(3)Mg10Cd2 cuboctahedra.