Ce4Y2O11 is alpha bismuth trifluoride-derived structured and crystallizes in the tetragonal P-4m2 space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to two equivalent O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. Y(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Y(1) atoms to form OY4 tetrahedra that share corners with four equivalent O(3)Ce2Y2 tetrahedra, corners with four equivalent O(1)Y4 tetrahedra, corners with eight equivalent O(2)Ce2Y2 tetrahedra, and edges with two equivalent O(3)Ce2Y2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Ce(1) and two equivalent Y(1) atoms to form OCe2Y2 tetrahedra that share corners with two equivalent O(5)Ce4 tetrahedra, corners with four equivalent O(2)Ce2Y2 tetrahedra, corners with four equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(1)Y4 tetrahedra,  an edgeedge with one O(5)Ce4 tetrahedra, and edges with four equivalent O(3)Ce2Y2 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ce(1) and two equivalent Y(1) atoms to form OCe2Y2 tetrahedra that share corners with two equivalent O(4)Ce4 tetrahedra, corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(3)Ce2Y2 tetrahedra, corners with four equivalent O(5)Ce4 tetrahedra,  an edgeedge with one O(4)Ce4 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with four equivalent O(2)Ce2Y2 tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(3)Ce2Y2 tetrahedra, corners with two equivalent O(7)Ce4 tetrahedra, corners with four equivalent O(2)Ce2Y2 tetrahedra, corners with four equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(6)Ce4 tetrahedra,  an edgeedge with one O(3)Ce2Y2 tetrahedra,  an edgeedge with one O(7)Ce4 tetrahedra, and edges with four equivalent O(5)Ce4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(2)Ce2Y2 tetrahedra, corners with two equivalent O(6)Ce4 tetrahedra, corners with four equivalent O(3)Ce2Y2 tetrahedra, corners with four equivalent O(5)Ce4 tetrahedra, corners with four equivalent O(7)Ce4 tetrahedra,  an edgeedge with one O(2)Ce2Y2 tetrahedra,  an edgeedge with one O(6)Ce4 tetrahedra, and edges with four equivalent O(4)Ce4 tetrahedra. In the sixth O site, O(6) is bonded to four equivalent Ce(2) atoms to form a mixture of edge and corner-sharing OCe4 tetrahedra. In the seventh O site, O(7) is bonded to four equivalent Ce(2) atoms to form a mixture of edge and corner-sharing OCe4 tetrahedra.
Ce4Y2O11 is alpha bismuth trifluoride-derived structured and crystallizes in the tetragonal P-4m2 space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. Both Ce(1)-O(2) bond lengths are 2.48 Å. Both Ce(1)-O(3) bond lengths are 2.29 Å. Both Ce(1)-O(4) bond lengths are 2.40 Å. Both Ce(1)-O(5) bond lengths are 2.33 Å. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to two equivalent O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. Both Ce(2)-O(4) bond lengths are 2.33 Å. Both Ce(2)-O(5) bond lengths are 2.40 Å. Both Ce(2)-O(6) bond lengths are 2.36 Å. Both Ce(2)-O(7) bond lengths are 2.36 Å. Y(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Both Y(1)-O(1) bond lengths are 2.46 Å. Both Y(1)-O(2) bond lengths are 2.17 Å. Both Y(1)-O(3) bond lengths are 2.34 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Y(1) atoms to form OY4 tetrahedra that share corners with four equivalent O(3)Ce2Y2 tetrahedra, corners with four equivalent O(1)Y4 tetrahedra, corners with eight equivalent O(2)Ce2Y2 tetrahedra, and edges with two equivalent O(3)Ce2Y2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Ce(1) and two equivalent Y(1) atoms to form OCe2Y2 tetrahedra that share corners with two equivalent O(5)Ce4 tetrahedra, corners with four equivalent O(2)Ce2Y2 tetrahedra, corners with four equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(1)Y4 tetrahedra,  an edgeedge with one O(5)Ce4 tetrahedra, and edges with four equivalent O(3)Ce2Y2 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ce(1) and two equivalent Y(1) atoms to form OCe2Y2 tetrahedra that share corners with two equivalent O(4)Ce4 tetrahedra, corners with two equivalent O(1)Y4 tetrahedra, corners with four equivalent O(3)Ce2Y2 tetrahedra, corners with four equivalent O(5)Ce4 tetrahedra,  an edgeedge with one O(4)Ce4 tetrahedra,  an edgeedge with one O(1)Y4 tetrahedra, and edges with four equivalent O(2)Ce2Y2 tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(3)Ce2Y2 tetrahedra, corners with two equivalent O(7)Ce4 tetrahedra, corners with four equivalent O(2)Ce2Y2 tetrahedra, corners with four equivalent O(4)Ce4 tetrahedra, corners with four equivalent O(6)Ce4 tetrahedra,  an edgeedge with one O(3)Ce2Y2 tetrahedra,  an edgeedge with one O(7)Ce4 tetrahedra, and edges with four equivalent O(5)Ce4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ce(1) and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(2)Ce2Y2 tetrahedra, corners with two equivalent O(6)Ce4 tetrahedra, corners with four equivalent O(3)Ce2Y2 tetrahedra, corners with four equivalent O(5)Ce4 tetrahedra, corners with four equivalent O(7)Ce4 tetrahedra,  an edgeedge with one O(2)Ce2Y2 tetrahedra,  an edgeedge with one O(6)Ce4 tetrahedra, and edges with four equivalent O(4)Ce4 tetrahedra. In the sixth O site, O(6) is bonded to four equivalent Ce(2) atoms to form a mixture of edge and corner-sharing OCe4 tetrahedra. In the seventh O site, O(7) is bonded to four equivalent Ce(2) atoms to form a mixture of edge and corner-sharing OCe4 tetrahedra.