Ce4La3O12 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one O(4), one O(5), one O(6), two equivalent O(1), and two equivalent O(3) atoms to form distorted CeO7 hexagonal pyramids that share  a cornercorner with one La(1)O6 octahedra and edges with two equivalent Ce(1)O7 hexagonal pyramids. The corner-sharing octahedral tilt angles are 58°. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to one O(1), one O(3), three equivalent O(4), and three equivalent O(6) atoms. There are two inequivalent La sites. In the first La site, La(1) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form LaO6 octahedra that share corners with two equivalent Ce(1)O7 hexagonal pyramids and edges with two equivalent La(1)O6 octahedra. In the second La site, La(2) is bonded in a 6-coordinate geometry to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Ce(2), two equivalent Ce(1), and one La(2) atom to form distorted OLaCe3 tetrahedra that share  a cornercorner with one O(6)Ce4 tetrahedra, corners with two equivalent O(2)La4 tetrahedra, corners with two equivalent O(1)LaCe3 tetrahedra, corners with two equivalent O(3)LaCe3 tetrahedra, corners with four equivalent O(5)La3Ce tetrahedra, corners with five equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(6)Ce4 tetrahedra, and edges with two equivalent O(3)LaCe3 tetrahedra. In the second O site, O(2) is bonded to two equivalent La(1) and two equivalent La(2) atoms to form distorted OLa4 tetrahedra that share corners with two equivalent O(1)LaCe3 tetrahedra, corners with two equivalent O(3)LaCe3 tetrahedra, corners with four equivalent O(5)La3Ce tetrahedra, corners with four equivalent O(2)La4 tetrahedra, edges with two equivalent O(5)La3Ce tetrahedra, and edges with two equivalent O(2)La4 tetrahedra. In the third O site, O(3) is bonded to one Ce(2), two equivalent Ce(1), and one La(2) atom to form OLaCe3 tetrahedra that share  a cornercorner with one O(4)Ce4 tetrahedra, corners with two equivalent O(2)La4 tetrahedra, corners with two equivalent O(1)LaCe3 tetrahedra, corners with two equivalent O(3)LaCe3 tetrahedra, corners with five equivalent O(6)Ce4 tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(5)La3Ce tetrahedra, and edges with two equivalent O(1)LaCe3 tetrahedra. In the fourth O site, O(4) is bonded to one Ce(1) and three equivalent Ce(2) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(5)La3Ce tetrahedra,  a cornercorner with one O(3)LaCe3 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, corners with five equivalent O(1)LaCe3 tetrahedra, corners with six equivalent O(6)Ce4 tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(6)Ce4 tetrahedra, and edges with two equivalent O(3)LaCe3 tetrahedra. In the fifth O site, O(5) is bonded to one Ce(1), one La(1), and two equivalent La(2) atoms to form OLa3Ce tetrahedra that share  a cornercorner with one O(4)Ce4 tetrahedra,  a cornercorner with one O(6)Ce4 tetrahedra, corners with three equivalent O(5)La3Ce tetrahedra, corners with four equivalent O(2)La4 tetrahedra, corners with four equivalent O(1)LaCe3 tetrahedra, edges with two equivalent O(2)La4 tetrahedra, and edges with two equivalent O(3)LaCe3 tetrahedra. In the sixth O site, O(6) is bonded to one Ce(1) and three equivalent Ce(2) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(5)La3Ce tetrahedra,  a cornercorner with one O(1)LaCe3 tetrahedra, corners with two equivalent O(6)Ce4 tetrahedra, corners with five equivalent O(3)LaCe3 tetrahedra, corners with six equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(6)Ce4 tetrahedra, and edges with two equivalent O(1)LaCe3 tetrahedra.
Ce4La3O12 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one O(4), one O(5), one O(6), two equivalent O(1), and two equivalent O(3) atoms to form distorted CeO7 hexagonal pyramids that share  a cornercorner with one La(1)O6 octahedra and edges with two equivalent Ce(1)O7 hexagonal pyramids. The corner-sharing octahedral tilt angles are 58°. The Ce(1)-O(4) bond length is 2.28 Å. The Ce(1)-O(5) bond length is 2.44 Å. The Ce(1)-O(6) bond length is 2.26 Å. Both Ce(1)-O(1) bond lengths are 2.45 Å. Both Ce(1)-O(3) bond lengths are 2.34 Å. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to one O(1), one O(3), three equivalent O(4), and three equivalent O(6) atoms. The Ce(2)-O(1) bond length is 2.62 Å. The Ce(2)-O(3) bond length is 2.31 Å. There are two shorter (2.37 Å) and one longer (2.41 Å) Ce(2)-O(4) bond length. There are two shorter (2.40 Å) and one longer (2.45 Å) Ce(2)-O(6) bond length. There are two inequivalent La sites. In the first La site, La(1) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form LaO6 octahedra that share corners with two equivalent Ce(1)O7 hexagonal pyramids and edges with two equivalent La(1)O6 octahedra. Both La(1)-O(5) bond lengths are 2.44 Å. All La(1)-O(2) bond lengths are 2.42 Å. In the second La site, La(2) is bonded in a 6-coordinate geometry to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms. The La(2)-O(1) bond length is 2.47 Å. The La(2)-O(3) bond length is 2.44 Å. There is one shorter (2.35 Å) and one longer (2.68 Å) La(2)-O(2) bond length. Both La(2)-O(5) bond lengths are 2.34 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Ce(2), two equivalent Ce(1), and one La(2) atom to form distorted OLaCe3 tetrahedra that share  a cornercorner with one O(6)Ce4 tetrahedra, corners with two equivalent O(2)La4 tetrahedra, corners with two equivalent O(1)LaCe3 tetrahedra, corners with two equivalent O(3)LaCe3 tetrahedra, corners with four equivalent O(5)La3Ce tetrahedra, corners with five equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(6)Ce4 tetrahedra, and edges with two equivalent O(3)LaCe3 tetrahedra. In the second O site, O(2) is bonded to two equivalent La(1) and two equivalent La(2) atoms to form distorted OLa4 tetrahedra that share corners with two equivalent O(1)LaCe3 tetrahedra, corners with two equivalent O(3)LaCe3 tetrahedra, corners with four equivalent O(5)La3Ce tetrahedra, corners with four equivalent O(2)La4 tetrahedra, edges with two equivalent O(5)La3Ce tetrahedra, and edges with two equivalent O(2)La4 tetrahedra. In the third O site, O(3) is bonded to one Ce(2), two equivalent Ce(1), and one La(2) atom to form OLaCe3 tetrahedra that share  a cornercorner with one O(4)Ce4 tetrahedra, corners with two equivalent O(2)La4 tetrahedra, corners with two equivalent O(1)LaCe3 tetrahedra, corners with two equivalent O(3)LaCe3 tetrahedra, corners with five equivalent O(6)Ce4 tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(5)La3Ce tetrahedra, and edges with two equivalent O(1)LaCe3 tetrahedra. In the fourth O site, O(4) is bonded to one Ce(1) and three equivalent Ce(2) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(5)La3Ce tetrahedra,  a cornercorner with one O(3)LaCe3 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, corners with five equivalent O(1)LaCe3 tetrahedra, corners with six equivalent O(6)Ce4 tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(6)Ce4 tetrahedra, and edges with two equivalent O(3)LaCe3 tetrahedra. In the fifth O site, O(5) is bonded to one Ce(1), one La(1), and two equivalent La(2) atoms to form OLa3Ce tetrahedra that share  a cornercorner with one O(4)Ce4 tetrahedra,  a cornercorner with one O(6)Ce4 tetrahedra, corners with three equivalent O(5)La3Ce tetrahedra, corners with four equivalent O(2)La4 tetrahedra, corners with four equivalent O(1)LaCe3 tetrahedra, edges with two equivalent O(2)La4 tetrahedra, and edges with two equivalent O(3)LaCe3 tetrahedra. In the sixth O site, O(6) is bonded to one Ce(1) and three equivalent Ce(2) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(5)La3Ce tetrahedra,  a cornercorner with one O(1)LaCe3 tetrahedra, corners with two equivalent O(6)Ce4 tetrahedra, corners with five equivalent O(3)LaCe3 tetrahedra, corners with six equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, edges with two equivalent O(6)Ce4 tetrahedra, and edges with two equivalent O(1)LaCe3 tetrahedra.