CeAl4 crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 16-coordinate geometry to two equivalent Al(3), two equivalent Al(4), two equivalent Al(5), two equivalent Al(8), four equivalent Al(6), and four equivalent Al(7) atoms. In the second Ce site, Ce(2) is bonded in a 16-coordinate geometry to one Al(3), one Al(4), two equivalent Al(1), two equivalent Al(2), two equivalent Al(6), two equivalent Al(7), three equivalent Al(5), and three equivalent Al(8) atoms. There are eight inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to four equivalent Ce(2), one Al(2), two equivalent Al(4), and two equivalent Al(5) atoms. In the second Al site, Al(2) is bonded in a 9-coordinate geometry to four equivalent Ce(2), one Al(1), two equivalent Al(3), and two equivalent Al(8) atoms. In the third Al site, Al(3) is bonded to two equivalent Ce(1), two equivalent Ce(2), two equivalent Al(2), two equivalent Al(6), and four equivalent Al(8) atoms to form a mixture of distorted edge, corner, and face-sharing AlCe4Al8 cuboctahedra. In the fourth Al site, Al(4) is bonded to two equivalent Ce(1), two equivalent Ce(2), two equivalent Al(1), two equivalent Al(7), and four equivalent Al(5) atoms to form a mixture of distorted edge, corner, and face-sharing AlCe4Al8 cuboctahedra. In the fifth Al site, Al(5) is bonded to one Ce(1), three equivalent Ce(2), one Al(1), one Al(6), two equivalent Al(4), two equivalent Al(7), and two equivalent Al(8) atoms to form a mixture of distorted edge, corner, and face-sharing AlCe4Al8 cuboctahedra. In the sixth Al site, Al(6) is bonded in a 9-coordinate geometry to two equivalent Ce(1), two equivalent Ce(2), one Al(3), one Al(5), one Al(7), and two equivalent Al(8) atoms. In the seventh Al site, Al(7) is bonded in a 9-coordinate geometry to two equivalent Ce(1), two equivalent Ce(2), one Al(4), one Al(6), one Al(8), and two equivalent Al(5) atoms. In the eighth Al site, Al(8) is bonded to one Ce(1), three equivalent Ce(2), one Al(2), one Al(7), two equivalent Al(3), two equivalent Al(5), and two equivalent Al(6) atoms to form a mixture of distorted edge, corner, and face-sharing AlCe4Al8 cuboctahedra.
CeAl4 crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 16-coordinate geometry to two equivalent Al(3), two equivalent Al(4), two equivalent Al(5), two equivalent Al(8), four equivalent Al(6), and four equivalent Al(7) atoms. Both Ce(1)-Al(3) bond lengths are 3.52 Å. Both Ce(1)-Al(4) bond lengths are 3.66 Å. Both Ce(1)-Al(5) bond lengths are 3.52 Å. Both Ce(1)-Al(8) bond lengths are 3.53 Å. All Ce(1)-Al(6) bond lengths are 3.29 Å. All Ce(1)-Al(7) bond lengths are 3.24 Å. In the second Ce site, Ce(2) is bonded in a 16-coordinate geometry to one Al(3), one Al(4), two equivalent Al(1), two equivalent Al(2), two equivalent Al(6), two equivalent Al(7), three equivalent Al(5), and three equivalent Al(8) atoms. The Ce(2)-Al(3) bond length is 3.53 Å. The Ce(2)-Al(4) bond length is 3.51 Å. Both Ce(2)-Al(1) bond lengths are 3.26 Å. Both Ce(2)-Al(2) bond lengths are 3.28 Å. Both Ce(2)-Al(6) bond lengths are 3.26 Å. Both Ce(2)-Al(7) bond lengths are 3.28 Å. There is one shorter (3.51 Å) and two longer (3.62 Å) Ce(2)-Al(5) bond lengths. There is one shorter (3.52 Å) and two longer (3.55 Å) Ce(2)-Al(8) bond lengths. There are eight inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to four equivalent Ce(2), one Al(2), two equivalent Al(4), and two equivalent Al(5) atoms. The Al(1)-Al(2) bond length is 2.51 Å. Both Al(1)-Al(4) bond lengths are 2.66 Å. Both Al(1)-Al(5) bond lengths are 2.67 Å. In the second Al site, Al(2) is bonded in a 9-coordinate geometry to four equivalent Ce(2), one Al(1), two equivalent Al(3), and two equivalent Al(8) atoms. Both Al(2)-Al(3) bond lengths are 2.64 Å. Both Al(2)-Al(8) bond lengths are 2.66 Å. In the third Al site, Al(3) is bonded to two equivalent Ce(1), two equivalent Ce(2), two equivalent Al(2), two equivalent Al(6), and four equivalent Al(8) atoms to form a mixture of distorted edge, corner, and face-sharing AlCe4Al8 cuboctahedra. Both Al(3)-Al(6) bond lengths are 2.66 Å. All Al(3)-Al(8) bond lengths are 3.05 Å. In the fourth Al site, Al(4) is bonded to two equivalent Ce(1), two equivalent Ce(2), two equivalent Al(1), two equivalent Al(7), and four equivalent Al(5) atoms to form a mixture of distorted edge, corner, and face-sharing AlCe4Al8 cuboctahedra. Both Al(4)-Al(7) bond lengths are 2.67 Å. All Al(4)-Al(5) bond lengths are 2.98 Å. In the fifth Al site, Al(5) is bonded to one Ce(1), three equivalent Ce(2), one Al(1), one Al(6), two equivalent Al(4), two equivalent Al(7), and two equivalent Al(8) atoms to form a mixture of distorted edge, corner, and face-sharing AlCe4Al8 cuboctahedra. The Al(5)-Al(6) bond length is 2.66 Å. Both Al(5)-Al(7) bond lengths are 2.66 Å. Both Al(5)-Al(8) bond lengths are 3.01 Å. In the sixth Al site, Al(6) is bonded in a 9-coordinate geometry to two equivalent Ce(1), two equivalent Ce(2), one Al(3), one Al(5), one Al(7), and two equivalent Al(8) atoms. The Al(6)-Al(7) bond length is 2.52 Å. Both Al(6)-Al(8) bond lengths are 2.65 Å. In the seventh Al site, Al(7) is bonded in a 9-coordinate geometry to two equivalent Ce(1), two equivalent Ce(2), one Al(4), one Al(6), one Al(8), and two equivalent Al(5) atoms. The Al(7)-Al(8) bond length is 2.66 Å. In the eighth Al site, Al(8) is bonded to one Ce(1), three equivalent Ce(2), one Al(2), one Al(7), two equivalent Al(3), two equivalent Al(5), and two equivalent Al(6) atoms to form a mixture of distorted edge, corner, and face-sharing AlCe4Al8 cuboctahedra.