Mg14CeSb crystallizes in the orthorhombic Amm2 space group. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Sb(1)Ce2Mg10 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(6)CeMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)CeMg10Sb cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Ce(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(5)CeMg10Sb cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Ce(1)Mg10Sb2 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)CeMg10Sb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Sb(1)Ce2Mg10 cuboctahedra, faces with four equivalent Mg(5)CeMg10Sb cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(6)CeMg11 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Ce(1), and two equivalent Sb(1) atoms to form distorted MgCe2Mg8Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Ce(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(5)CeMg10Sb cuboctahedra, edges with four equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Ce(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Ce2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)CeMg10Sb cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, corners with four equivalent Ce(1)Mg10Sb2 cuboctahedra, corners with four equivalent Sb(1)Ce2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)CeMg10Sb cuboctahedra, edges with four equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, and faces with eight equivalent Mg(5)CeMg10Sb cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), one Ce(1), and one Sb(1) atom to form distorted MgCeMg10Sb cuboctahedra that share corners with four equivalent Mg(6)CeMg11 cuboctahedra, corners with ten equivalent Mg(5)CeMg10Sb cuboctahedra, edges with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(5)CeMg10Sb cuboctahedra, edges with two equivalent Mg(6)CeMg11 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Ce(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Ce2Mg10 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Ce(1)Mg10Sb2 cuboctahedra,  a faceface with one Sb(1)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)CeMg10Sb cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. In the sixth Mg site, Mg(6) is bonded to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), four equivalent Mg(5), and one Ce(1) atom to form MgCeMg11 cuboctahedra that share corners with six equivalent Mg(6)CeMg11 cuboctahedra, corners with eight equivalent Mg(5)CeMg10Sb cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Ce(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(5)CeMg10Sb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Ce(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(2)Mg12 cuboctahedra, faces with three equivalent Sb(1)Ce2Mg10 cuboctahedra, and faces with four equivalent Mg(5)CeMg10Sb cuboctahedra. In the seventh Mg site, Mg(7) is bonded in a distorted single-bond geometry to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), four equivalent Mg(5), and one Sb(1) atom. Ce(1) is bonded to two equivalent Mg(6), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Sb(1) atoms to form CeMg10Sb2 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Ce(1)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Sb(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(6)CeMg11 cuboctahedra, edges with eight equivalent Mg(5)CeMg10Sb cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Sb(1)Ce2Mg10 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, and faces with four equivalent Mg(5)CeMg10Sb cuboctahedra. Sb(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Ce(1) atoms to form SbCe2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Sb(1)Ce2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Ce(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with eight equivalent Mg(5)CeMg10Sb cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Ce(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)CeMg10Sb cuboctahedra, and faces with six equivalent Mg(6)CeMg11 cuboctahedra.
Mg14CeSb crystallizes in the orthorhombic Amm2 space group. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Sb(1)Ce2Mg10 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(6)CeMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)CeMg10Sb cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Ce(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(5)CeMg10Sb cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.19 Å. Both Mg(1)-Mg(6) bond lengths are 3.16 Å. There are two shorter (3.25 Å) and two longer (3.27 Å) Mg(1)-Mg(4) bond lengths. All Mg(1)-Mg(5) bond lengths are 3.13 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Ce(1)Mg10Sb2 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)CeMg10Sb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Sb(1)Ce2Mg10 cuboctahedra, faces with four equivalent Mg(5)CeMg10Sb cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(6)CeMg11 cuboctahedra. Both Mg(2)-Mg(7) bond lengths are 3.24 Å. There are two shorter (3.24 Å) and two longer (3.28 Å) Mg(2)-Mg(4) bond lengths. All Mg(2)-Mg(5) bond lengths are 3.13 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Ce(1), and two equivalent Sb(1) atoms to form distorted MgCe2Mg8Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Ce(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(5)CeMg10Sb cuboctahedra, edges with four equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Ce(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Ce2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)CeMg10Sb cuboctahedra. There is one shorter (3.12 Å) and one longer (3.26 Å) Mg(3)-Mg(3) bond length. Both Mg(3)-Mg(5) bond lengths are 3.27 Å. Both Mg(3)-Mg(6) bond lengths are 3.23 Å. Both Mg(3)-Mg(7) bond lengths are 3.18 Å. There is one shorter (3.26 Å) and one longer (3.27 Å) Mg(3)-Ce(1) bond length. There is one shorter (3.20 Å) and one longer (3.32 Å) Mg(3)-Sb(1) bond length. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, corners with four equivalent Ce(1)Mg10Sb2 cuboctahedra, corners with four equivalent Sb(1)Ce2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)CeMg10Sb cuboctahedra, edges with four equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, and faces with eight equivalent Mg(5)CeMg10Sb cuboctahedra. There is one shorter (3.17 Å) and one longer (3.21 Å) Mg(4)-Mg(4) bond length. Both Mg(4)-Mg(5) bond lengths are 3.13 Å. Both Mg(4)-Mg(6) bond lengths are 3.14 Å. Both Mg(4)-Mg(7) bond lengths are 3.21 Å. In the fifth Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), one Ce(1), and one Sb(1) atom to form distorted MgCeMg10Sb cuboctahedra that share corners with four equivalent Mg(6)CeMg11 cuboctahedra, corners with ten equivalent Mg(5)CeMg10Sb cuboctahedra, edges with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(5)CeMg10Sb cuboctahedra, edges with two equivalent Mg(6)CeMg11 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Ce(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Ce2Mg10 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Ce(1)Mg10Sb2 cuboctahedra,  a faceface with one Sb(1)Ce2Mg10 cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)CeMg10Sb cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. There is one shorter (3.18 Å) and one longer (3.20 Å) Mg(5)-Mg(5) bond length. There is one shorter (3.22 Å) and one longer (3.30 Å) Mg(5)-Mg(6) bond length. There is one shorter (3.23 Å) and one longer (3.30 Å) Mg(5)-Mg(7) bond length. The Mg(5)-Ce(1) bond length is 3.28 Å. The Mg(5)-Sb(1) bond length is 3.27 Å. In the sixth Mg site, Mg(6) is bonded to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), four equivalent Mg(5), and one Ce(1) atom to form MgCeMg11 cuboctahedra that share corners with six equivalent Mg(6)CeMg11 cuboctahedra, corners with eight equivalent Mg(5)CeMg10Sb cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Ce(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(5)CeMg10Sb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Ce(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(2)Mg12 cuboctahedra, faces with three equivalent Sb(1)Ce2Mg10 cuboctahedra, and faces with four equivalent Mg(5)CeMg10Sb cuboctahedra. Both Mg(6)-Mg(7) bond lengths are 3.19 Å. The Mg(6)-Ce(1) bond length is 3.28 Å. In the seventh Mg site, Mg(7) is bonded in a distorted single-bond geometry to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), four equivalent Mg(5), and one Sb(1) atom. The Mg(7)-Sb(1) bond length is 3.22 Å. Ce(1) is bonded to two equivalent Mg(6), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Sb(1) atoms to form CeMg10Sb2 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Ce(1)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Sb(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(6)CeMg11 cuboctahedra, edges with eight equivalent Mg(5)CeMg10Sb cuboctahedra, faces with two equivalent Mg(6)CeMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Sb(1)Ce2Mg10 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, and faces with four equivalent Mg(5)CeMg10Sb cuboctahedra. Both Ce(1)-Sb(1) bond lengths are 3.19 Å. Sb(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Ce(1) atoms to form SbCe2Mg10 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Sb(1)Ce2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Ce(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, edges with eight equivalent Mg(5)CeMg10Sb cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Ce(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(3)Ce2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)CeMg10Sb cuboctahedra, and faces with six equivalent Mg(6)CeMg11 cuboctahedra.