Mg6CdSi 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(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cd(1), and two equivalent Si(1) atoms to form distorted MgMg8Cd2Si2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Si2 cuboctahedra, corners with ten equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, edges with two equivalent Mg(2)Mg10Si2 cuboctahedra, edges with two equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cd2 cuboctahedra, edges with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(2)Mg10Si2 cuboctahedra, faces with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, and faces with eight equivalent Mg(3)Mg8Cd2Si2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Si(1) atoms to form distorted MgMg10Si2 cuboctahedra that share corners with six equivalent Mg(2)Mg10Si2 cuboctahedra, corners with eight equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cd2 cuboctahedra, edges with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, edges with eight equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(2)Mg10Si2 cuboctahedra, faces with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, and faces with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra. In the third Mg site, Mg(3) 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 Si(1) atoms to form distorted MgMg8Cd2Si2 cuboctahedra that share corners with four equivalent Mg(4)Mg10Cd2 cuboctahedra, corners with ten equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, edges with two equivalent Mg(4)Mg10Cd2 cuboctahedra, edges with two equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, edges with four equivalent Mg(2)Mg10Si2 cuboctahedra, edges with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(2)Mg10Si2 cuboctahedra, faces with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, and faces with eight equivalent Mg(1)Mg8Cd2Si2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cd(1) atoms to form distorted MgMg10Cd2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Cd2 cuboctahedra, corners with eight equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, edges with four equivalent Mg(2)Mg10Si2 cuboctahedra, edges with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, edges with eight equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(2)Mg10Si2 cuboctahedra, faces with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, and faces with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra. Cd(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms. Si(1) is bonded in a 8-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms.
Mg6CdSi 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(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cd(1), and two equivalent Si(1) atoms to form distorted MgMg8Cd2Si2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Si2 cuboctahedra, corners with ten equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, edges with two equivalent Mg(2)Mg10Si2 cuboctahedra, edges with two equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cd2 cuboctahedra, edges with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(2)Mg10Si2 cuboctahedra, faces with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, and faces with eight equivalent Mg(3)Mg8Cd2Si2 cuboctahedra. There is one shorter (3.06 Å) and one longer (3.08 Å) Mg(1)-Mg(1) bond length. There is one shorter (3.10 Å) and one longer (3.14 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.18 Å. Both Mg(1)-Mg(4) bond lengths are 3.10 Å. Both Mg(1)-Cd(1) bond lengths are 3.06 Å. There is one shorter (3.00 Å) and one longer (3.23 Å) Mg(1)-Si(1) bond length. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Si(1) atoms to form distorted MgMg10Si2 cuboctahedra that share corners with six equivalent Mg(2)Mg10Si2 cuboctahedra, corners with eight equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cd2 cuboctahedra, edges with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, edges with eight equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(2)Mg10Si2 cuboctahedra, faces with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, and faces with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.12 Å. All Mg(2)-Mg(3) bond lengths are 3.10 Å. Both Mg(2)-Si(1) bond lengths are 3.07 Å. In the third Mg site, Mg(3) 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 Si(1) atoms to form distorted MgMg8Cd2Si2 cuboctahedra that share corners with four equivalent Mg(4)Mg10Cd2 cuboctahedra, corners with ten equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, edges with two equivalent Mg(4)Mg10Cd2 cuboctahedra, edges with two equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, edges with four equivalent Mg(2)Mg10Si2 cuboctahedra, edges with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(2)Mg10Si2 cuboctahedra, faces with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, and faces with eight equivalent Mg(1)Mg8Cd2Si2 cuboctahedra. There is one shorter (2.99 Å) and one longer (3.15 Å) Mg(3)-Mg(3) bond length. There is one shorter (3.08 Å) and one longer (3.16 Å) Mg(3)-Mg(4) bond length. There is one shorter (3.10 Å) and one longer (3.14 Å) Mg(3)-Cd(1) bond length. Both Mg(3)-Si(1) bond lengths are 3.03 Å. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cd(1) atoms to form distorted MgMg10Cd2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Cd2 cuboctahedra, corners with eight equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, edges with four equivalent Mg(2)Mg10Si2 cuboctahedra, edges with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra, edges with eight equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cd2 cuboctahedra, faces with two equivalent Mg(2)Mg10Si2 cuboctahedra, faces with four equivalent Mg(1)Mg8Cd2Si2 cuboctahedra, and faces with four equivalent Mg(3)Mg8Cd2Si2 cuboctahedra. Both Mg(4)-Cd(1) bond lengths are 3.07 Å. Cd(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms. Si(1) is bonded in a 8-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms.