Mg6CeZr 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 Zr(1) atoms to form MgCe2Mg8Zr2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Zr2 cuboctahedra, corners with ten equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Mg(2)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(4)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with four equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, and faces with eight equivalent Mg(3)Ce2Mg8Zr2 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 Zr(1) atoms to form MgMg10Zr2 cuboctahedra that share corners with six equivalent Mg(2)Mg10Zr2 cuboctahedra, corners with eight equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with four equivalent Mg(4)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with eight equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, and faces with six equivalent Ce(1)Mg10Zr2 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 Ce(1), and two equivalent Zr(1) atoms to form distorted MgCe2Mg8Zr2 cuboctahedra that share corners with four equivalent Mg(4)Ce2Mg10 cuboctahedra, corners with four equivalent Ce(1)Mg10Zr2 cuboctahedra, corners with ten equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Mg(4)Ce2Mg10 cuboctahedra, edges with two equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Ce(1)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with four equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, and faces with eight equivalent Mg(1)Ce2Mg8Zr2 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 Ce(1) atoms to form distorted MgCe2Mg10 cuboctahedra that share corners with four equivalent Ce(1)Mg10Zr2 cuboctahedra, corners with six equivalent Mg(4)Ce2Mg10 cuboctahedra, corners with eight equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Ce(1)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with four equivalent Mg(2)Mg10Zr2 cuboctahedra, edges with eight equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, and faces with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra. Ce(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Zr(1) atoms to form distorted CeMg10Zr2 cuboctahedra that share corners with four equivalent Mg(4)Ce2Mg10 cuboctahedra, corners with six equivalent Ce(1)Mg10Zr2 cuboctahedra, corners with eight equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Mg(4)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with eight equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, and faces with six equivalent Mg(2)Mg10Zr2 cuboctahedra. Zr(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Ce(1) atoms.
Mg6CeZr 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 Zr(1) atoms to form MgCe2Mg8Zr2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Zr2 cuboctahedra, corners with ten equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Mg(2)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(4)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with four equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, and faces with eight equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra. There is one shorter (3.18 Å) and one longer (3.35 Å) Mg(1)-Mg(1) bond length. There is one shorter (3.30 Å) and one longer (3.37 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.05 Å. Both Mg(1)-Mg(4) bond lengths are 3.18 Å. Both Mg(1)-Ce(1) bond lengths are 3.32 Å. There is one shorter (3.23 Å) and one longer (3.45 Å) Mg(1)-Zr(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 Zr(1) atoms to form MgMg10Zr2 cuboctahedra that share corners with six equivalent Mg(2)Mg10Zr2 cuboctahedra, corners with eight equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with four equivalent Mg(4)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with eight equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, and faces with six equivalent Ce(1)Mg10Zr2 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.14 Å. All Mg(2)-Mg(3) bond lengths are 3.24 Å. Both Mg(2)-Zr(1) bond lengths are 3.27 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 Ce(1), and two equivalent Zr(1) atoms to form distorted MgCe2Mg8Zr2 cuboctahedra that share corners with four equivalent Mg(4)Ce2Mg10 cuboctahedra, corners with four equivalent Ce(1)Mg10Zr2 cuboctahedra, corners with ten equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Mg(4)Ce2Mg10 cuboctahedra, edges with two equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Ce(1)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, edges with four equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, and faces with eight equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra. There is one shorter (3.14 Å) and one longer (3.39 Å) Mg(3)-Mg(3) bond length. There is one shorter (3.23 Å) and one longer (3.44 Å) Mg(3)-Mg(4) bond length. There is one shorter (3.16 Å) and one longer (3.52 Å) Mg(3)-Ce(1) bond length. Both Mg(3)-Zr(1) bond lengths are 3.26 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 Ce(1) atoms to form distorted MgCe2Mg10 cuboctahedra that share corners with four equivalent Ce(1)Mg10Zr2 cuboctahedra, corners with six equivalent Mg(4)Ce2Mg10 cuboctahedra, corners with eight equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Ce(1)Mg10Zr2 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with four equivalent Mg(2)Mg10Zr2 cuboctahedra, edges with eight equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(2)Mg10Zr2 cuboctahedra, faces with two equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, and faces with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra. Both Mg(4)-Ce(1) bond lengths are 3.27 Å. Ce(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Zr(1) atoms to form distorted CeMg10Zr2 cuboctahedra that share corners with four equivalent Mg(4)Ce2Mg10 cuboctahedra, corners with six equivalent Ce(1)Mg10Zr2 cuboctahedra, corners with eight equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with two equivalent Mg(4)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, edges with eight equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, faces with two equivalent Mg(4)Ce2Mg10 cuboctahedra, faces with two equivalent Ce(1)Mg10Zr2 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg8Zr2 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Zr2 cuboctahedra, and faces with six equivalent Mg(2)Mg10Zr2 cuboctahedra. Both Ce(1)-Zr(1) bond lengths are 2.88 Å. Zr(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Ce(1) atoms.