Ce3Y4O12 crystallizes in the monoclinic Cm space group. There are three inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to one O(10), one O(12), one O(3), one O(6), two equivalent O(11), and two equivalent O(4) atoms. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to one O(1), one O(11), one O(4), one O(8), two equivalent O(10), and two equivalent O(6) atoms. In the third Ce site, Ce(3) is bonded to one O(11), one O(4), one O(5), two equivalent O(12), and two equivalent O(3) atoms to form distorted CeO7 hexagonal pyramids that share  a cornercorner with one Y(2)O6 octahedra and edges with two equivalent Ce(3)O7 hexagonal pyramids. The corner-sharing octahedral tilt angles are 64°. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded in a 6-coordinate geometry to one O(12), one O(2), one O(3), one O(7), and two equivalent O(5) atoms. In the second Y site, Y(2) is bonded to one O(5), one O(9), two equivalent O(2), and two equivalent O(7) atoms to form distorted YO6 octahedra that share  a cornercorner with one Ce(3)O7 hexagonal pyramid and edges with two equivalent Y(2)O6 octahedra. In the third Y site, Y(3) is bonded in a 7-coordinate geometry to one O(10), one O(6), one O(9), two equivalent O(1), and two equivalent O(8) atoms. In the fourth Y site, Y(4) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(7), one O(8), and two equivalent O(9) atoms. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Ce(2), one Y(4), and two equivalent Y(3) atoms to form distorted OCeY3 tetrahedra that share  a cornercorner with one O(11)Ce4 tetrahedra,  a cornercorner with one O(4)Ce4 tetrahedra, corners with two equivalent O(1)CeY3 tetrahedra, corners with two equivalent O(8)CeY3 tetrahedra, corners with four equivalent O(6)Ce3Y tetrahedra, corners with four equivalent O(9)Y4 tetrahedra,  a cornercorner with one O(2)Y4 trigonal pyramid,  a cornercorner with one O(7)Y4 trigonal pyramid, edges with two equivalent O(10)Ce3Y tetrahedra, and edges with two equivalent O(8)CeY3 tetrahedra. In the second O site, O(2) is bonded to one Y(1), one Y(4), and two equivalent Y(2) atoms to form distorted OY4 trigonal pyramids that share  a cornercorner with one O(12)Ce3Y tetrahedra,  a cornercorner with one O(3)Ce3Y tetrahedra,  a cornercorner with one O(1)CeY3 tetrahedra,  a cornercorner with one O(8)CeY3 tetrahedra, corners with four equivalent O(9)Y4 tetrahedra, corners with two equivalent O(2)Y4 trigonal pyramids, corners with two equivalent O(7)Y4 trigonal pyramids, edges with two equivalent O(5)CeY3 tetrahedra, and edges with two equivalent O(7)Y4 trigonal pyramids. In the third O site, O(3) is bonded to one Ce(1), two equivalent Ce(3), and one Y(1) atom to form OCe3Y tetrahedra that share  a cornercorner with one O(10)Ce3Y tetrahedra,  a cornercorner with one O(6)Ce3Y tetrahedra, corners with two equivalent O(12)Ce3Y tetrahedra, corners with two equivalent O(3)Ce3Y tetrahedra, corners with four equivalent O(11)Ce4 tetrahedra,  a cornercorner with one O(2)Y4 trigonal pyramid,  a cornercorner with one O(7)Y4 trigonal pyramid, edges with two equivalent O(12)Ce3Y tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, and edges with two equivalent O(5)CeY3 tetrahedra. In the fourth O site, O(4) is bonded to one Ce(2), one Ce(3), and two equivalent Ce(1) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(1)CeY3 tetrahedra,  a cornercorner with one O(5)CeY3 tetrahedra,  a cornercorner with one O(8)CeY3 tetrahedra, corners with two equivalent O(11)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(10)Ce3Y tetrahedra, corners with four equivalent O(12)Ce3Y tetrahedra, edges with two equivalent O(3)Ce3Y tetrahedra, edges with two equivalent O(6)Ce3Y tetrahedra, and edges with two equivalent O(11)Ce4 tetrahedra. In the fifth O site, O(5) is bonded to one Ce(3), one Y(2), and two equivalent Y(1) atoms to form OCeY3 tetrahedra that share  a cornercorner with one O(11)Ce4 tetrahedra,  a cornercorner with one O(4)Ce4 tetrahedra,  a cornercorner with one O(9)Y4 tetrahedra, corners with two equivalent O(5)CeY3 tetrahedra, corners with four equivalent O(12)Ce3Y tetrahedra, corners with four equivalent O(7)Y4 trigonal pyramids, edges with two equivalent O(3)Ce3Y tetrahedra, and edges with two equivalent O(2)Y4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Ce(1), two equivalent Ce(2), and one Y(3) atom to form OCe3Y tetrahedra that share  a cornercorner with one O(12)Ce3Y tetrahedra,  a cornercorner with one O(3)Ce3Y tetrahedra,  a cornercorner with one O(9)Y4 tetrahedra, corners with two equivalent O(10)Ce3Y tetrahedra, corners with two equivalent O(6)Ce3Y tetrahedra, corners with four equivalent O(11)Ce4 tetrahedra, corners with four equivalent O(1)CeY3 tetrahedra, edges with two equivalent O(10)Ce3Y tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, and edges with two equivalent O(8)CeY3 tetrahedra. In the seventh O site, O(7) is bonded to one Y(1), one Y(4), and two equivalent Y(2) atoms to form distorted OY4 trigonal pyramids that share  a cornercorner with one O(12)Ce3Y tetrahedra,  a cornercorner with one O(3)Ce3Y tetrahedra,  a cornercorner with one O(1)CeY3 tetrahedra,  a cornercorner with one O(8)CeY3 tetrahedra, corners with four equivalent O(5)CeY3 tetrahedra, corners with two equivalent O(2)Y4 trigonal pyramids, corners with two equivalent O(7)Y4 trigonal pyramids, edges with two equivalent O(9)Y4 tetrahedra, and edges with two equivalent O(2)Y4 trigonal pyramids. In the eighth O site, O(8) is bonded to one Ce(2), one Y(4), and two equivalent Y(3) atoms to form OCeY3 tetrahedra that share  a cornercorner with one O(11)Ce4 tetrahedra,  a cornercorner with one O(4)Ce4 tetrahedra, corners with two equivalent O(1)CeY3 tetrahedra, corners with two equivalent O(8)CeY3 tetrahedra, corners with four equivalent O(10)Ce3Y tetrahedra,  a cornercorner with one O(2)Y4 trigonal pyramid,  a cornercorner with one O(7)Y4 trigonal pyramid, edges with two equivalent O(6)Ce3Y tetrahedra, edges with two equivalent O(1)CeY3 tetrahedra, and edges with two equivalent O(9)Y4 tetrahedra. In the ninth O site, O(9) is bonded to one Y(2), one Y(3), and two equivalent Y(4) atoms to form OY4 tetrahedra that share  a cornercorner with one O(10)Ce3Y tetrahedra,  a cornercorner with one O(6)Ce3Y tetrahedra,  a cornercorner with one O(5)CeY3 tetrahedra, corners with two equivalent O(9)Y4 tetrahedra, corners with four equivalent O(1)CeY3 tetrahedra, corners with four equivalent O(2)Y4 trigonal pyramids, edges with two equivalent O(8)CeY3 tetrahedra, and edges with two equivalent O(7)Y4 trigonal pyramids. In the tenth O site, O(10) is bonded to one Ce(1), two equivalent Ce(2), and one Y(3) atom to form OCe3Y tetrahedra that share  a cornercorner with one O(12)Ce3Y tetrahedra,  a cornercorner with one O(3)Ce3Y tetrahedra,  a cornercorner with one O(9)Y4 tetrahedra, corners with two equivalent O(10)Ce3Y tetrahedra, corners with two equivalent O(6)Ce3Y tetrahedra, corners with four equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(8)CeY3 tetrahedra, edges with two equivalent O(6)Ce3Y tetrahedra, edges with two equivalent O(11)Ce4 tetrahedra, and edges with two equivalent O(1)CeY3 tetrahedra. In the eleventh O site, O(11) is bonded to one Ce(2), one Ce(3), and two equivalent Ce(1) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(1)CeY3 tetrahedra,  a cornercorner with one O(5)CeY3 tetrahedra,  a cornercorner with one O(8)CeY3 tetrahedra, corners with two equivalent O(11)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(3)Ce3Y tetrahedra, corners with four equivalent O(6)Ce3Y tetrahedra, edges with two equivalent O(10)Ce3Y tetrahedra, edges with two equivalent O(12)Ce3Y tetrahedra, and edges with two equivalent O(4)Ce4 tetrahedra. In the twelfth O site, O(12) is bonded to one Ce(1), two equivalent Ce(3), and one Y(1) atom to form distorted OCe3Y tetrahedra that share  a cornercorner with one O(10)Ce3Y tetrahedra,  a cornercorner with one O(6)Ce3Y tetrahedra, corners with two equivalent O(12)Ce3Y tetrahedra, corners with two equivalent O(3)Ce3Y tetrahedra, corners with four equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(5)CeY3 tetrahedra,  a cornercorner with one O(2)Y4 trigonal pyramid,  a cornercorner with one O(7)Y4 trigonal pyramid, edges with two equivalent O(3)Ce3Y tetrahedra, and edges with two equivalent O(11)Ce4 tetrahedra.
Ce3Y4O12 crystallizes in the monoclinic Cm space group. There are three inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to one O(10), one O(12), one O(3), one O(6), two equivalent O(11), and two equivalent O(4) atoms. The Ce(1)-O(10) bond length is 2.38 Å. The Ce(1)-O(12) bond length is 2.66 Å. The Ce(1)-O(3) bond length is 2.34 Å. The Ce(1)-O(6) bond length is 2.33 Å. Both Ce(1)-O(11) bond lengths are 2.35 Å. Both Ce(1)-O(4) bond lengths are 2.31 Å. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to one O(1), one O(11), one O(4), one O(8), two equivalent O(10), and two equivalent O(6) atoms. The Ce(2)-O(1) bond length is 2.49 Å. The Ce(2)-O(11) bond length is 2.53 Å. The Ce(2)-O(4) bond length is 2.52 Å. The Ce(2)-O(8) bond length is 2.20 Å. Both Ce(2)-O(10) bond lengths are 2.34 Å. Both Ce(2)-O(6) bond lengths are 2.33 Å. In the third Ce site, Ce(3) is bonded to one O(11), one O(4), one O(5), two equivalent O(12), and two equivalent O(3) atoms to form distorted CeO7 hexagonal pyramids that share  a cornercorner with one Y(2)O6 octahedra and edges with two equivalent Ce(3)O7 hexagonal pyramids. The corner-sharing octahedral tilt angles are 64°. The Ce(3)-O(11) bond length is 2.26 Å. The Ce(3)-O(4) bond length is 2.28 Å. The Ce(3)-O(5) bond length is 2.42 Å. Both Ce(3)-O(12) bond lengths are 2.39 Å. Both Ce(3)-O(3) bond lengths are 2.29 Å. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded in a 6-coordinate geometry to one O(12), one O(2), one O(3), one O(7), and two equivalent O(5) atoms. The Y(1)-O(12) bond length is 2.41 Å. The Y(1)-O(2) bond length is 2.45 Å. The Y(1)-O(3) bond length is 2.38 Å. The Y(1)-O(7) bond length is 2.21 Å. Both Y(1)-O(5) bond lengths are 2.22 Å. In the second Y site, Y(2) is bonded to one O(5), one O(9), two equivalent O(2), and two equivalent O(7) atoms to form distorted YO6 octahedra that share  a cornercorner with one Ce(3)O7 hexagonal pyramid and edges with two equivalent Y(2)O6 octahedra. The Y(2)-O(5) bond length is 2.30 Å. The Y(2)-O(9) bond length is 2.24 Å. Both Y(2)-O(2) bond lengths are 2.36 Å. Both Y(2)-O(7) bond lengths are 2.35 Å. In the third Y site, Y(3) is bonded in a 7-coordinate geometry to one O(10), one O(6), one O(9), two equivalent O(1), and two equivalent O(8) atoms. The Y(3)-O(10) bond length is 2.29 Å. The Y(3)-O(6) bond length is 2.31 Å. The Y(3)-O(9) bond length is 2.43 Å. Both Y(3)-O(1) bond lengths are 2.43 Å. Both Y(3)-O(8) bond lengths are 2.29 Å. In the fourth Y site, Y(4) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(7), one O(8), and two equivalent O(9) atoms. The Y(4)-O(1) bond length is 2.29 Å. The Y(4)-O(2) bond length is 2.27 Å. The Y(4)-O(7) bond length is 2.62 Å. The Y(4)-O(8) bond length is 2.30 Å. Both Y(4)-O(9) bond lengths are 2.22 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Ce(2), one Y(4), and two equivalent Y(3) atoms to form distorted OCeY3 tetrahedra that share  a cornercorner with one O(11)Ce4 tetrahedra,  a cornercorner with one O(4)Ce4 tetrahedra, corners with two equivalent O(1)CeY3 tetrahedra, corners with two equivalent O(8)CeY3 tetrahedra, corners with four equivalent O(6)Ce3Y tetrahedra, corners with four equivalent O(9)Y4 tetrahedra,  a cornercorner with one O(2)Y4 trigonal pyramid,  a cornercorner with one O(7)Y4 trigonal pyramid, edges with two equivalent O(10)Ce3Y tetrahedra, and edges with two equivalent O(8)CeY3 tetrahedra. In the second O site, O(2) is bonded to one Y(1), one Y(4), and two equivalent Y(2) atoms to form distorted OY4 trigonal pyramids that share  a cornercorner with one O(12)Ce3Y tetrahedra,  a cornercorner with one O(3)Ce3Y tetrahedra,  a cornercorner with one O(1)CeY3 tetrahedra,  a cornercorner with one O(8)CeY3 tetrahedra, corners with four equivalent O(9)Y4 tetrahedra, corners with two equivalent O(2)Y4 trigonal pyramids, corners with two equivalent O(7)Y4 trigonal pyramids, edges with two equivalent O(5)CeY3 tetrahedra, and edges with two equivalent O(7)Y4 trigonal pyramids. In the third O site, O(3) is bonded to one Ce(1), two equivalent Ce(3), and one Y(1) atom to form OCe3Y tetrahedra that share  a cornercorner with one O(10)Ce3Y tetrahedra,  a cornercorner with one O(6)Ce3Y tetrahedra, corners with two equivalent O(12)Ce3Y tetrahedra, corners with two equivalent O(3)Ce3Y tetrahedra, corners with four equivalent O(11)Ce4 tetrahedra,  a cornercorner with one O(2)Y4 trigonal pyramid,  a cornercorner with one O(7)Y4 trigonal pyramid, edges with two equivalent O(12)Ce3Y tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, and edges with two equivalent O(5)CeY3 tetrahedra. In the fourth O site, O(4) is bonded to one Ce(2), one Ce(3), and two equivalent Ce(1) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(1)CeY3 tetrahedra,  a cornercorner with one O(5)CeY3 tetrahedra,  a cornercorner with one O(8)CeY3 tetrahedra, corners with two equivalent O(11)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(10)Ce3Y tetrahedra, corners with four equivalent O(12)Ce3Y tetrahedra, edges with two equivalent O(3)Ce3Y tetrahedra, edges with two equivalent O(6)Ce3Y tetrahedra, and edges with two equivalent O(11)Ce4 tetrahedra. In the fifth O site, O(5) is bonded to one Ce(3), one Y(2), and two equivalent Y(1) atoms to form OCeY3 tetrahedra that share  a cornercorner with one O(11)Ce4 tetrahedra,  a cornercorner with one O(4)Ce4 tetrahedra,  a cornercorner with one O(9)Y4 tetrahedra, corners with two equivalent O(5)CeY3 tetrahedra, corners with four equivalent O(12)Ce3Y tetrahedra, corners with four equivalent O(7)Y4 trigonal pyramids, edges with two equivalent O(3)Ce3Y tetrahedra, and edges with two equivalent O(2)Y4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Ce(1), two equivalent Ce(2), and one Y(3) atom to form OCe3Y tetrahedra that share  a cornercorner with one O(12)Ce3Y tetrahedra,  a cornercorner with one O(3)Ce3Y tetrahedra,  a cornercorner with one O(9)Y4 tetrahedra, corners with two equivalent O(10)Ce3Y tetrahedra, corners with two equivalent O(6)Ce3Y tetrahedra, corners with four equivalent O(11)Ce4 tetrahedra, corners with four equivalent O(1)CeY3 tetrahedra, edges with two equivalent O(10)Ce3Y tetrahedra, edges with two equivalent O(4)Ce4 tetrahedra, and edges with two equivalent O(8)CeY3 tetrahedra. In the seventh O site, O(7) is bonded to one Y(1), one Y(4), and two equivalent Y(2) atoms to form distorted OY4 trigonal pyramids that share  a cornercorner with one O(12)Ce3Y tetrahedra,  a cornercorner with one O(3)Ce3Y tetrahedra,  a cornercorner with one O(1)CeY3 tetrahedra,  a cornercorner with one O(8)CeY3 tetrahedra, corners with four equivalent O(5)CeY3 tetrahedra, corners with two equivalent O(2)Y4 trigonal pyramids, corners with two equivalent O(7)Y4 trigonal pyramids, edges with two equivalent O(9)Y4 tetrahedra, and edges with two equivalent O(2)Y4 trigonal pyramids. In the eighth O site, O(8) is bonded to one Ce(2), one Y(4), and two equivalent Y(3) atoms to form OCeY3 tetrahedra that share  a cornercorner with one O(11)Ce4 tetrahedra,  a cornercorner with one O(4)Ce4 tetrahedra, corners with two equivalent O(1)CeY3 tetrahedra, corners with two equivalent O(8)CeY3 tetrahedra, corners with four equivalent O(10)Ce3Y tetrahedra,  a cornercorner with one O(2)Y4 trigonal pyramid,  a cornercorner with one O(7)Y4 trigonal pyramid, edges with two equivalent O(6)Ce3Y tetrahedra, edges with two equivalent O(1)CeY3 tetrahedra, and edges with two equivalent O(9)Y4 tetrahedra. In the ninth O site, O(9) is bonded to one Y(2), one Y(3), and two equivalent Y(4) atoms to form OY4 tetrahedra that share  a cornercorner with one O(10)Ce3Y tetrahedra,  a cornercorner with one O(6)Ce3Y tetrahedra,  a cornercorner with one O(5)CeY3 tetrahedra, corners with two equivalent O(9)Y4 tetrahedra, corners with four equivalent O(1)CeY3 tetrahedra, corners with four equivalent O(2)Y4 trigonal pyramids, edges with two equivalent O(8)CeY3 tetrahedra, and edges with two equivalent O(7)Y4 trigonal pyramids. In the tenth O site, O(10) is bonded to one Ce(1), two equivalent Ce(2), and one Y(3) atom to form OCe3Y tetrahedra that share  a cornercorner with one O(12)Ce3Y tetrahedra,  a cornercorner with one O(3)Ce3Y tetrahedra,  a cornercorner with one O(9)Y4 tetrahedra, corners with two equivalent O(10)Ce3Y tetrahedra, corners with two equivalent O(6)Ce3Y tetrahedra, corners with four equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(8)CeY3 tetrahedra, edges with two equivalent O(6)Ce3Y tetrahedra, edges with two equivalent O(11)Ce4 tetrahedra, and edges with two equivalent O(1)CeY3 tetrahedra. In the eleventh O site, O(11) is bonded to one Ce(2), one Ce(3), and two equivalent Ce(1) atoms to form OCe4 tetrahedra that share  a cornercorner with one O(1)CeY3 tetrahedra,  a cornercorner with one O(5)CeY3 tetrahedra,  a cornercorner with one O(8)CeY3 tetrahedra, corners with two equivalent O(11)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(3)Ce3Y tetrahedra, corners with four equivalent O(6)Ce3Y tetrahedra, edges with two equivalent O(10)Ce3Y tetrahedra, edges with two equivalent O(12)Ce3Y tetrahedra, and edges with two equivalent O(4)Ce4 tetrahedra. In the twelfth O site, O(12) is bonded to one Ce(1), two equivalent Ce(3), and one Y(1) atom to form distorted OCe3Y tetrahedra that share  a cornercorner with one O(10)Ce3Y tetrahedra,  a cornercorner with one O(6)Ce3Y tetrahedra, corners with two equivalent O(12)Ce3Y tetrahedra, corners with two equivalent O(3)Ce3Y tetrahedra, corners with four equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(5)CeY3 tetrahedra,  a cornercorner with one O(2)Y4 trigonal pyramid,  a cornercorner with one O(7)Y4 trigonal pyramid, edges with two equivalent O(3)Ce3Y tetrahedra, and edges with two equivalent O(11)Ce4 tetrahedra.