Mg6CeSn 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 Ce(1), and two equivalent Sn(1) atoms to form distorted MgCe2Mg8Sn2 cuboctahedra that share corners with four equivalent Ce(1)Mg10Sn2 cuboctahedra, corners with four equivalent Sn(1)Ce2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, edges with two equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, edges with two equivalent Ce(1)Mg10Sn2 cuboctahedra, edges with two equivalent Sn(1)Ce2Mg10 cuboctahedra, faces with two equivalent Ce(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Ce2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Ce(1), and two equivalent Sn(1) atoms. In the third Mg site, Mg(3) is bonded in a distorted water-like geometry to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms. Ce(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms to form distorted CeMg10Sn2 cuboctahedra that share corners with four equivalent Sn(1)Ce2Mg10 cuboctahedra, corners with six equivalent Ce(1)Mg10Sn2 cuboctahedra, corners with eight equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, edges with two equivalent Sn(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, faces with two equivalent Ce(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Ce2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra. Sn(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms to form distorted SnCe2Mg10 cuboctahedra that share corners with four equivalent Ce(1)Mg10Sn2 cuboctahedra, corners with six equivalent Sn(1)Ce2Mg10 cuboctahedra, corners with eight equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, edges with two equivalent Ce(1)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, faces with two equivalent Ce(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Ce2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra.
Mg6CeSn 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 Ce(1), and two equivalent Sn(1) atoms to form distorted MgCe2Mg8Sn2 cuboctahedra that share corners with four equivalent Ce(1)Mg10Sn2 cuboctahedra, corners with four equivalent Sn(1)Ce2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, edges with two equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, edges with two equivalent Ce(1)Mg10Sn2 cuboctahedra, edges with two equivalent Sn(1)Ce2Mg10 cuboctahedra, faces with two equivalent Ce(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Ce2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra. There is one shorter (3.18 Å) and one longer (3.21 Å) Mg(1)-Mg(1) bond length. Both Mg(1)-Mg(2) bond lengths are 3.18 Å. Both Mg(1)-Mg(3) bond lengths are 3.26 Å. Both Mg(1)-Mg(4) bond lengths are 3.22 Å. There is one shorter (3.35 Å) and one longer (3.41 Å) Mg(1)-Ce(1) bond length. There is one shorter (3.28 Å) and one longer (3.48 Å) Mg(1)-Sn(1) bond length. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Ce(1), and two equivalent Sn(1) atoms. There is one shorter (3.17 Å) and one longer (3.22 Å) Mg(2)-Mg(2) bond length. There is one shorter (3.36 Å) and one longer (3.40 Å) Mg(2)-Mg(3) bond length. There is one shorter (3.26 Å) and one longer (3.50 Å) Mg(2)-Mg(4) bond length. Both Mg(2)-Ce(1) bond lengths are 3.28 Å. Both Mg(2)-Sn(1) bond lengths are 3.24 Å. In the third Mg site, Mg(3) is bonded in a distorted water-like geometry to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms. Both Mg(3)-Mg(4) bond lengths are 3.20 Å. Both Mg(3)-Sn(1) bond lengths are 3.26 Å. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms. Both Mg(4)-Ce(1) bond lengths are 3.25 Å. Ce(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms to form distorted CeMg10Sn2 cuboctahedra that share corners with four equivalent Sn(1)Ce2Mg10 cuboctahedra, corners with six equivalent Ce(1)Mg10Sn2 cuboctahedra, corners with eight equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, edges with two equivalent Sn(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, faces with two equivalent Ce(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Ce2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra. Both Ce(1)-Sn(1) bond lengths are 3.20 Å. Sn(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms to form distorted SnCe2Mg10 cuboctahedra that share corners with four equivalent Ce(1)Mg10Sn2 cuboctahedra, corners with six equivalent Sn(1)Ce2Mg10 cuboctahedra, corners with eight equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, edges with two equivalent Ce(1)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra, faces with two equivalent Ce(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Ce2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Ce2Mg8Sn2 cuboctahedra.