Mg14CeBi crystallizes in the hexagonal P-6m2 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(4); four Mg(1,1); four equivalent Mg(3); and two equivalent Ce(1) atoms to form MgCe2Mg10 cuboctahedra that share corners with four equivalent Bi(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Ce2Mg10 cuboctahedra; corners with eight equivalent Mg(2)Mg10Bi2 cuboctahedra; edges with two equivalent Ce(1)Mg12 cuboctahedra; edges with four Mg(1,1)Ce2Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)CeMg10Bi cuboctahedra; faces with two equivalent Mg(2)Mg10Bi2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Ce(1)Mg12 cuboctahedra; faces with four Mg(1,1)Ce2Mg10 cuboctahedra; and faces with ten equivalent Mg(3)CeMg10Bi cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Bi(1) atoms to form distorted MgMg10Bi2 cuboctahedra that share corners with four equivalent Ce(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Bi2 cuboctahedra; corners with eight Mg(1,1)Ce2Mg10 cuboctahedra; edges with two equivalent Bi(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Mg10Bi2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)CeMg10Bi cuboctahedra; faces with two equivalent Mg(1)Ce2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Bi(1)Mg12 cuboctahedra; faces with four equivalent Mg(2)Mg10Bi2 cuboctahedra; and faces with ten equivalent Mg(3)CeMg10Bi cuboctahedra. In the third Mg site, Mg(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Ce(1) atoms to form MgCe2Mg10 cuboctahedra that share corners with four equivalent Bi(1)Mg12 cuboctahedra, corners with six equivalent Mg(1)Ce2Mg10 cuboctahedra, corners with eight equivalent Mg(2)Mg10Bi2 cuboctahedra, edges with two equivalent Ce(1)Mg12 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(3)CeMg10Bi cuboctahedra, faces with two equivalent Mg(2)Mg10Bi2 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Ce(1)Mg12 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg10 cuboctahedra, and faces with ten equivalent Mg(3)CeMg10Bi cuboctahedra. In the fourth Mg site, Mg(3) is bonded to two Mg(1,1); two equivalent Mg(2); two equivalent Mg(4); four equivalent Mg(3); one Ce(1); and one Bi(1) atom to form distorted MgCeMg10Bi cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen equivalent Mg(3)CeMg10Bi cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Ce(1)Mg12 cuboctahedra; edges with two equivalent Bi(1)Mg12 cuboctahedra; edges with four Mg(1,1)Ce2Mg10 cuboctahedra; edges with four equivalent Mg(3)CeMg10Bi cuboctahedra; edges with four equivalent Mg(2)Mg10Bi2 cuboctahedra;  a faceface with one Ce(1)Mg12 cuboctahedra;  a faceface with one Bi(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(1,1)Ce2Mg10 cuboctahedra; faces with five equivalent Mg(2)Mg10Bi2 cuboctahedra; and faces with six equivalent Mg(3)CeMg10Bi cuboctahedra. In the fifth Mg site, Mg(4) is bonded to three Mg(1,1); three equivalent Mg(2); and six equivalent Mg(3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve equivalent Mg(3)CeMg10Bi cuboctahedra; edges with six Mg(1,1)Ce2Mg10 cuboctahedra; edges with six equivalent Mg(3)CeMg10Bi cuboctahedra; edges with six equivalent Mg(2)Mg10Bi2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three Mg(1,1)Ce2Mg10 cuboctahedra; faces with three equivalent Mg(2)Mg10Bi2 cuboctahedra; faces with three equivalent Ce(1)Mg12 cuboctahedra; faces with three equivalent Bi(1)Mg12 cuboctahedra; and faces with six equivalent Mg(3)CeMg10Bi cuboctahedra. Ce(1) is bonded to six Mg(1,1) and six equivalent Mg(3) atoms to form CeMg12 cuboctahedra that share corners with six equivalent Ce(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(2)Mg10Bi2 cuboctahedra; edges with six Mg(1,1)Ce2Mg10 cuboctahedra; edges with twelve equivalent Mg(3)CeMg10Bi cuboctahedra; faces with two equivalent Bi(1)Mg12 cuboctahedra; faces with six Mg(1,1)Ce2Mg10 cuboctahedra; faces with six equivalent Mg(3)CeMg10Bi cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra. Bi(1) is bonded to six equivalent Mg(2) and six equivalent Mg(3) atoms to form BiMg12 cuboctahedra that share corners with six equivalent Bi(1)Mg12 cuboctahedra; corners with twelve Mg(1,1)Ce2Mg10 cuboctahedra; edges with six equivalent Mg(2)Mg10Bi2 cuboctahedra; edges with twelve equivalent Mg(3)CeMg10Bi cuboctahedra; faces with two equivalent Ce(1)Mg12 cuboctahedra; faces with six equivalent Mg(3)CeMg10Bi cuboctahedra; faces with six equivalent Mg(2)Mg10Bi2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra.
Mg14CeBi crystallizes in the hexagonal P-6m2 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(4); four Mg(1,1); four equivalent Mg(3); and two equivalent Ce(1) atoms to form MgCe2Mg10 cuboctahedra that share corners with four equivalent Bi(1)Mg12 cuboctahedra; corners with six equivalent Mg(1)Ce2Mg10 cuboctahedra; corners with eight equivalent Mg(2)Mg10Bi2 cuboctahedra; edges with two equivalent Ce(1)Mg12 cuboctahedra; edges with four Mg(1,1)Ce2Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)CeMg10Bi cuboctahedra; faces with two equivalent Mg(2)Mg10Bi2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Ce(1)Mg12 cuboctahedra; faces with four Mg(1,1)Ce2Mg10 cuboctahedra; and faces with ten equivalent Mg(3)CeMg10Bi cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.26 Å. There are two shorter (3.19 Å) and two longer (3.36 Å) Mg(1)-Mg(1,1) bond lengths. All Mg(1)-Mg(3) bond lengths are 3.28 Å. Both Mg(1)-Ce(1) bond lengths are 3.28 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Bi(1) atoms to form distorted MgMg10Bi2 cuboctahedra that share corners with four equivalent Ce(1)Mg12 cuboctahedra; corners with six equivalent Mg(2)Mg10Bi2 cuboctahedra; corners with eight Mg(1,1)Ce2Mg10 cuboctahedra; edges with two equivalent Bi(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Mg10Bi2 cuboctahedra; edges with four equivalent Mg(4)Mg12 cuboctahedra; edges with eight equivalent Mg(3)CeMg10Bi cuboctahedra; faces with two equivalent Mg(1)Ce2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with two equivalent Bi(1)Mg12 cuboctahedra; faces with four equivalent Mg(2)Mg10Bi2 cuboctahedra; and faces with ten equivalent Mg(3)CeMg10Bi cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.35 Å. There are two shorter (3.24 Å) and two longer (3.31 Å) Mg(2)-Mg(2) bond lengths. All Mg(2)-Mg(3) bond lengths are 3.30 Å. Both Mg(2)-Bi(1) bond lengths are 3.28 Å. In the third Mg site, Mg(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Ce(1) atoms to form MgCe2Mg10 cuboctahedra that share corners with four equivalent Bi(1)Mg12 cuboctahedra, corners with six equivalent Mg(1)Ce2Mg10 cuboctahedra, corners with eight equivalent Mg(2)Mg10Bi2 cuboctahedra, edges with two equivalent Ce(1)Mg12 cuboctahedra, edges with four equivalent Mg(1)Ce2Mg10 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(3)CeMg10Bi cuboctahedra, faces with two equivalent Mg(2)Mg10Bi2 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Ce(1)Mg12 cuboctahedra, faces with four equivalent Mg(1)Ce2Mg10 cuboctahedra, and faces with ten equivalent Mg(3)CeMg10Bi cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.26 Å. All Mg(1)-Mg(3) bond lengths are 3.28 Å. Both Mg(1)-Ce(1) bond lengths are 3.28 Å. In the fourth Mg site, Mg(3) is bonded to two Mg(1,1); two equivalent Mg(2); two equivalent Mg(4); four equivalent Mg(3); one Ce(1); and one Bi(1) atom to form distorted MgCeMg10Bi cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra; corners with fourteen equivalent Mg(3)CeMg10Bi cuboctahedra; edges with two equivalent Mg(4)Mg12 cuboctahedra; edges with two equivalent Ce(1)Mg12 cuboctahedra; edges with two equivalent Bi(1)Mg12 cuboctahedra; edges with four Mg(1,1)Ce2Mg10 cuboctahedra; edges with four equivalent Mg(3)CeMg10Bi cuboctahedra; edges with four equivalent Mg(2)Mg10Bi2 cuboctahedra;  a faceface with one Ce(1)Mg12 cuboctahedra;  a faceface with one Bi(1)Mg12 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with five Mg(1,1)Ce2Mg10 cuboctahedra; faces with five equivalent Mg(2)Mg10Bi2 cuboctahedra; and faces with six equivalent Mg(3)CeMg10Bi cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.28 Å. There are two shorter (3.26 Å) and two longer (3.29 Å) Mg(3)-Mg(3) bond lengths. The Mg(3)-Ce(1) bond length is 3.30 Å. The Mg(3)-Bi(1) bond length is 3.30 Å. In the fifth Mg site, Mg(4) is bonded to three Mg(1,1); three equivalent Mg(2); and six equivalent Mg(3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra; corners with twelve equivalent Mg(3)CeMg10Bi cuboctahedra; edges with six Mg(1,1)Ce2Mg10 cuboctahedra; edges with six equivalent Mg(3)CeMg10Bi cuboctahedra; edges with six equivalent Mg(2)Mg10Bi2 cuboctahedra; faces with two equivalent Mg(4)Mg12 cuboctahedra; faces with three Mg(1,1)Ce2Mg10 cuboctahedra; faces with three equivalent Mg(2)Mg10Bi2 cuboctahedra; faces with three equivalent Ce(1)Mg12 cuboctahedra; faces with three equivalent Bi(1)Mg12 cuboctahedra; and faces with six equivalent Mg(3)CeMg10Bi cuboctahedra. Ce(1) is bonded to six Mg(1,1) and six equivalent Mg(3) atoms to form CeMg12 cuboctahedra that share corners with six equivalent Ce(1)Mg12 cuboctahedra; corners with twelve equivalent Mg(2)Mg10Bi2 cuboctahedra; edges with six Mg(1,1)Ce2Mg10 cuboctahedra; edges with twelve equivalent Mg(3)CeMg10Bi cuboctahedra; faces with two equivalent Bi(1)Mg12 cuboctahedra; faces with six Mg(1,1)Ce2Mg10 cuboctahedra; faces with six equivalent Mg(3)CeMg10Bi cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra. Bi(1) is bonded to six equivalent Mg(2) and six equivalent Mg(3) atoms to form BiMg12 cuboctahedra that share corners with six equivalent Bi(1)Mg12 cuboctahedra; corners with twelve Mg(1,1)Ce2Mg10 cuboctahedra; edges with six equivalent Mg(2)Mg10Bi2 cuboctahedra; edges with twelve equivalent Mg(3)CeMg10Bi cuboctahedra; faces with two equivalent Ce(1)Mg12 cuboctahedra; faces with six equivalent Mg(3)CeMg10Bi cuboctahedra; faces with six equivalent Mg(2)Mg10Bi2 cuboctahedra; and faces with six equivalent Mg(4)Mg12 cuboctahedra.