Mg6ZnSb 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 Zn(1), and two equivalent Sb(1) atoms to form distorted MgMg4Zn2Sb2 cuboctahedra that share corners with two equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with two equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, corners with five equivalent Sb(1)Mg10Zn2 cuboctahedra, corners with six equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, corners with six equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(3)Mg10Zn2 cuboctahedra, edges with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with five equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra,  a faceface with one Mg(1)Mg4Zn2Sb2 cuboctahedra,  a faceface with one Sb(1)Mg10Zn2 cuboctahedra, faces with two equivalent Mg(4)Mg6Sb2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, and faces with six equivalent Mg(2)Mg8Zn2Sb2 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 Zn(1), and two equivalent Sb(1) atoms to form distorted MgMg8Zn2Sb2 cuboctahedra that share corners with two equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, corners with two equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with four equivalent Mg(3)Mg10Zn2 cuboctahedra, corners with ten equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Zn2 cuboctahedra, edges with two equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with three equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, edges with four equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with four equivalent Sb(1)Mg10Zn2 cuboctahedra,  a faceface with one Mg(4)Mg6Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Zn2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Zn2 cuboctahedra, faces with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, and faces with six equivalent Mg(1)Mg4Zn2Sb2 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 Zn(1) atoms to form distorted MgMg10Zn2 cuboctahedra that share corners with six equivalent Mg(3)Mg10Zn2 cuboctahedra, corners with eight equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with four equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Zn2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, and faces with six equivalent Sb(1)Mg10Zn2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(3), four equivalent Mg(2), and two equivalent Sb(1) atoms to form distorted MgMg6Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, corners with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, corners with four equivalent Sb(1)Mg10Zn2 cuboctahedra, corners with eight equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Zn2 cuboctahedra, edges with four equivalent Mg(3)Mg10Zn2 cuboctahedra, edges with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, edges with six equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, faces with two equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, faces with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, and faces with four equivalent Zn(1)Mg10Sb2 cuboctahedra. Zn(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form ZnMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)Mg10Zn2 cuboctahedra, corners with six equivalent Zn(1)Mg10Sb2 cuboctahedra, corners with twelve equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Zn2 cuboctahedra, edges with four equivalent Mg(3)Mg10Zn2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Zn2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Zn2 cuboctahedra, faces with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, faces with four equivalent Mg(4)Mg6Sb2 cuboctahedra, and faces with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra. Sb(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Zn(1) atoms to form SbMg10Zn2 cuboctahedra that share corners with four equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with four equivalent Zn(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Mg10Zn2 cuboctahedra, corners with ten equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, faces with two equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Zn2 cuboctahedra, faces with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, and faces with six equivalent Mg(3)Mg10Zn2 cuboctahedra.
Mg6ZnSb 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 Zn(1), and two equivalent Sb(1) atoms to form distorted MgMg4Zn2Sb2 cuboctahedra that share corners with two equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with two equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, corners with five equivalent Sb(1)Mg10Zn2 cuboctahedra, corners with six equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, corners with six equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(3)Mg10Zn2 cuboctahedra, edges with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with five equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra,  a faceface with one Mg(1)Mg4Zn2Sb2 cuboctahedra,  a faceface with one Sb(1)Mg10Zn2 cuboctahedra, faces with two equivalent Mg(4)Mg6Sb2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, and faces with six equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.15 Å. Both Mg(1)-Mg(3) bond lengths are 3.18 Å. There is one shorter (3.07 Å) and one longer (3.12 Å) Mg(1)-Zn(1) bond length. There is one shorter (3.09 Å) and one longer (3.10 Å) Mg(1)-Sb(1) bond length. 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 Zn(1), and two equivalent Sb(1) atoms to form distorted MgMg8Zn2Sb2 cuboctahedra that share corners with two equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, corners with two equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with four equivalent Mg(3)Mg10Zn2 cuboctahedra, corners with ten equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with two equivalent Mg(3)Mg10Zn2 cuboctahedra, edges with two equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with three equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, edges with four equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with four equivalent Sb(1)Mg10Zn2 cuboctahedra,  a faceface with one Mg(4)Mg6Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Zn2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Zn2 cuboctahedra, faces with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, and faces with six equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra. There is one shorter (3.14 Å) and one longer (3.33 Å) Mg(2)-Mg(2) bond length. There is one shorter (3.04 Å) and one longer (3.15 Å) Mg(2)-Mg(3) bond length. There is one shorter (3.09 Å) and one longer (3.11 Å) Mg(2)-Mg(4) bond length. Both Mg(2)-Zn(1) bond lengths are 3.16 Å. Both Mg(2)-Sb(1) bond lengths are 3.20 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 Zn(1) atoms to form distorted MgMg10Zn2 cuboctahedra that share corners with six equivalent Mg(3)Mg10Zn2 cuboctahedra, corners with eight equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, edges with four equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Zn2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, and faces with six equivalent Sb(1)Mg10Zn2 cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.24 Å. Both Mg(3)-Zn(1) bond lengths are 3.12 Å. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(3), four equivalent Mg(2), and two equivalent Sb(1) atoms to form distorted MgMg6Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, corners with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, corners with four equivalent Sb(1)Mg10Zn2 cuboctahedra, corners with eight equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Zn2 cuboctahedra, edges with four equivalent Mg(3)Mg10Zn2 cuboctahedra, edges with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, edges with six equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, faces with two equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, faces with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, and faces with four equivalent Zn(1)Mg10Sb2 cuboctahedra. Both Mg(4)-Sb(1) bond lengths are 3.14 Å. Zn(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sb(1) atoms to form ZnMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)Mg10Zn2 cuboctahedra, corners with six equivalent Zn(1)Mg10Sb2 cuboctahedra, corners with twelve equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Sb(1)Mg10Zn2 cuboctahedra, edges with four equivalent Mg(3)Mg10Zn2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, faces with two equivalent Mg(3)Mg10Zn2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Zn2 cuboctahedra, faces with four equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, faces with four equivalent Mg(4)Mg6Sb2 cuboctahedra, and faces with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra. Both Zn(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 Zn(1) atoms to form SbMg10Zn2 cuboctahedra that share corners with four equivalent Mg(4)Mg6Sb2 cuboctahedra, corners with four equivalent Zn(1)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Mg10Zn2 cuboctahedra, corners with ten equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, edges with two equivalent Mg(4)Mg6Sb2 cuboctahedra, edges with two equivalent Zn(1)Mg10Sb2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, faces with two equivalent Mg(1)Mg4Zn2Sb2 cuboctahedra, faces with two equivalent Zn(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Mg10Zn2 cuboctahedra, faces with four equivalent Mg(2)Mg8Zn2Sb2 cuboctahedra, and faces with six equivalent Mg(3)Mg10Zn2 cuboctahedra.