TbCeO4 is Fluorite-derived structured and crystallizes in the monoclinic Cm space group. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a body-centered cubic geometry to one O(1,12); one O(5); one O(7); one O(8,11); two equivalent O(3); and two O(6,6) atoms. In the second Tb site, Tb(2) is bonded in a body-centered cubic geometry to one O(1,12); one O(5); one O(7); one O(8,11); two equivalent O(2); and two equivalent O(9) atoms. In the third Tb site, Tb(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(2); one O(3); one O(5); one O(6); one O(7); one O(8,11); and one O(9) atom. In the fourth Tb site, Tb(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(2); one O(3); one O(5); one O(6); one O(7); one O(8,11); and one O(9) atom. There are five inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(4); one O(8,11); two equivalent O(3); and two O(6,6) atoms. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(4); one O(8,11); two equivalent O(2); and two equivalent O(9) atoms. In the third Ce site, Ce(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(2); one O(3); one O(4); one O(6); one O(8,11); and one O(9) atom. In the fourth Ce site, Ce(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(2); one O(3); one O(4); one O(6); one O(8,11); and one O(9) atom. In the fifth Ce site, Ce(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(2); one O(3); one O(4); one O(6); one O(8,11); and one O(9) atom. There are sixteen inequivalent O sites. In the first O site, O(1,12) is bonded to one Tb(1); one Tb(2); and two Ce(3,3) atoms to form OTb2Ce2 tetrahedra that share corners with two equivalent O(4)Ce4 tetrahedra; corners with two equivalent O(5)Tb4 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; and edges with two equivalent O(3)Tb2Ce2 tetrahedra. In the second O site, O(2) is bonded to one Tb(2), one Tb(3), one Ce(2), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(10,10)Ce4 tetrahedra; corners with two equivalent O(2)Tb2Ce2 tetrahedra; corners with two equivalent O(3)Tb2Ce2 tetrahedra; corners with two equivalent O(7)Tb4 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(4)Ce4 tetrahedra;  an edgeedge with one O(6)Tb2Ce2 tetrahedra;  an edgeedge with one O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(5)Tb4 tetrahedra; and edges with two equivalent O(1,12)Tb2Ce2 tetrahedra. In the third O site, O(3) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(10,10)Ce4 tetrahedra; corners with two equivalent O(2)Tb2Ce2 tetrahedra; corners with two equivalent O(3)Tb2Ce2 tetrahedra; corners with two equivalent O(7)Tb4 tetrahedra; corners with four equivalent O(6)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra;  an edgeedge with one O(4)Ce4 tetrahedra;  an edgeedge with one O(6)Tb2Ce2 tetrahedra;  an edgeedge with one O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(5)Tb4 tetrahedra; and edges with two equivalent O(1,12)Tb2Ce2 tetrahedra. In the fourth O site, O(4) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with four O(10,10)Ce4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; edges with two equivalent O(3)Tb2Ce2 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the fifth O site, O(5) is bonded to one Tb(1), one Tb(2), and two equivalent Tb(3) atoms to form OTb4 tetrahedra that share corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra; corners with four equivalent O(7)Tb4 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; edges with two equivalent O(3)Tb2Ce2 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the sixth O site, O(6) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(4,4)Ce4 tetrahedra; corners with two equivalent O(6)Tb2Ce2 tetrahedra; corners with two equivalent O(9)Tb2Ce2 tetrahedra; corners with two O(5,5)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(3)Tb2Ce2 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the seventh O site, O(6) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(4,4)Ce4 tetrahedra; corners with two equivalent O(6)Tb2Ce2 tetrahedra; corners with two equivalent O(9)Tb2Ce2 tetrahedra; corners with two O(5,5)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(3)Tb2Ce2 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the eighth O site, O(7) is bonded to one Tb(1), one Tb(2), and two equivalent Tb(3) atoms to form OTb4 tetrahedra that share corners with four equivalent O(2)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; corners with four O(5,5)Tb4 tetrahedra; edges with two equivalent O(1,12)Tb2Ce2 tetrahedra; edges with two O(6,6)Tb2Ce2 tetrahedra; and edges with two equivalent O(9)Tb2Ce2 tetrahedra. In the ninth O site, O(8,11) is bonded to one Tb(1), one Tb(2), and two equivalent Ce(3) atoms to form OTb2Ce2 tetrahedra that share corners with two equivalent O(10)Ce4 tetrahedra; corners with two equivalent O(7)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four equivalent O(2)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra;  an edgeedge with one O(4)Ce4 tetrahedra;  an edgeedge with one O(5)Tb4 tetrahedra; edges with two O(6,6)Tb2Ce2 tetrahedra; and edges with two equivalent O(9)Tb2Ce2 tetrahedra. In the tenth O site, O(9) is bonded to one Tb(2), one Tb(3), one Ce(2), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(4,4)Ce4 tetrahedra; corners with two equivalent O(6)Tb2Ce2 tetrahedra; corners with two equivalent O(9)Tb2Ce2 tetrahedra; corners with two O(5,5)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four equivalent O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(3)Tb2Ce2 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the eleventh O site, O(10) is bonded to one Ce(1); one Ce(2); and two Ce(3,3) atoms to form OCe4 tetrahedra that share corners with four O(4,4)Ce4 tetrahedra; corners with four equivalent O(2)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; edges with two equivalent O(1,12)Tb2Ce2 tetrahedra; edges with two O(6,6)Tb2Ce2 tetrahedra; and edges with two equivalent O(9)Tb2Ce2 tetrahedra. In the twelfth O site, O(3) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(10,10)Ce4 tetrahedra; corners with two equivalent O(2)Tb2Ce2 tetrahedra; corners with two equivalent O(3)Tb2Ce2 tetrahedra; corners with two equivalent O(7)Tb4 tetrahedra; corners with four equivalent O(6)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra;  an edgeedge with one O(4)Ce4 tetrahedra;  an edgeedge with one O(6)Tb2Ce2 tetrahedra;  an edgeedge with one O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(5)Tb4 tetrahedra; and edges with two equivalent O(1,12)Tb2Ce2 tetrahedra. In the thirteenth O site, O(4) is bonded to one Ce(1); one Ce(2); and two Ce(3,3) atoms to form OCe4 tetrahedra that share corners with four O(10,10)Ce4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; edges with two equivalent O(3)Tb2Ce2 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the fourteenth O site, O(5) is bonded to one Tb(1), one Tb(2), and two equivalent Tb(3) atoms to form OTb4 tetrahedra that share corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra; corners with four equivalent O(7)Tb4 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; edges with two equivalent O(3)Tb2Ce2 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the fifteenth O site, O(6) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(4,4)Ce4 tetrahedra; corners with two equivalent O(6)Tb2Ce2 tetrahedra; corners with two equivalent O(9)Tb2Ce2 tetrahedra; corners with two O(5,5)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(3)Tb2Ce2 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the sixteenth O site, O(10) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with four O(4,4)Ce4 tetrahedra; corners with four equivalent O(2)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; edges with two equivalent O(1,12)Tb2Ce2 tetrahedra; edges with two O(6,6)Tb2Ce2 tetrahedra; and edges with two equivalent O(9)Tb2Ce2 tetrahedra.
TbCeO4 is Fluorite-derived structured and crystallizes in the monoclinic Cm space group. There are four inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a body-centered cubic geometry to one O(1,12); one O(5); one O(7); one O(8,11); two equivalent O(3); and two O(6,6) atoms. The Tb(1)-O(1,12) bond length is 2.42 Å. The Tb(1)-O(5) bond length is 2.37 Å. The Tb(1)-O(7) bond length is 2.37 Å. The Tb(1)-O(8,11) bond length is 2.42 Å. Both Tb(1)-O(3) bond lengths are 2.36 Å. Both Tb(1)-O(6,6) bond lengths are 2.42 Å. In the second Tb site, Tb(2) is bonded in a body-centered cubic geometry to one O(1,12); one O(5); one O(7); one O(8,11); two equivalent O(2); and two equivalent O(9) atoms. The Tb(2)-O(1,12) bond length is 2.42 Å. The Tb(2)-O(5) bond length is 2.37 Å. The Tb(2)-O(7) bond length is 2.37 Å. The Tb(2)-O(8,11) bond length is 2.42 Å. Both Tb(2)-O(2) bond lengths are 2.42 Å. Both Tb(2)-O(9) bond lengths are 2.42 Å. In the third Tb site, Tb(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(2); one O(3); one O(5); one O(6); one O(7); one O(8,11); and one O(9) atom. The Tb(3)-O(1,12) bond length is 2.42 Å. The Tb(3)-O(2) bond length is 2.42 Å. The Tb(3)-O(3) bond length is 2.36 Å. The Tb(3)-O(5) bond length is 2.37 Å. The Tb(3)-O(6) bond length is 2.42 Å. The Tb(3)-O(7) bond length is 2.37 Å. The Tb(3)-O(8,11) bond length is 2.42 Å. The Tb(3)-O(9) bond length is 2.42 Å. In the fourth Tb site, Tb(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(2); one O(3); one O(5); one O(6); one O(7); one O(8,11); and one O(9) atom. The Tb(3)-O(1,12) bond length is 2.42 Å. The Tb(3)-O(2) bond length is 2.42 Å. The Tb(3)-O(3) bond length is 2.36 Å. The Tb(3)-O(5) bond length is 2.37 Å. The Tb(3)-O(6) bond length is 2.42 Å. The Tb(3)-O(7) bond length is 2.37 Å. The Tb(3)-O(8,11) bond length is 2.42 Å. The Tb(3)-O(9) bond length is 2.42 Å. There are five inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(4); one O(8,11); two equivalent O(3); and two O(6,6) atoms. The Ce(1)-O(1,12) bond length is 2.32 Å. The Ce(1)-O(10) bond length is 2.37 Å. The Ce(1)-O(4) bond length is 2.37 Å. The Ce(1)-O(8,11) bond length is 2.32 Å. Both Ce(1)-O(3) bond lengths are 2.38 Å. Both Ce(1)-O(6,6) bond lengths are 2.32 Å. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(4); one O(8,11); two equivalent O(2); and two equivalent O(9) atoms. The Ce(2)-O(1,12) bond length is 2.32 Å. The Ce(2)-O(10) bond length is 2.37 Å. The Ce(2)-O(4) bond length is 2.37 Å. The Ce(2)-O(8,11) bond length is 2.32 Å. Both Ce(2)-O(2) bond lengths are 2.32 Å. Both Ce(2)-O(9) bond lengths are 2.32 Å. In the third Ce site, Ce(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(2); one O(3); one O(4); one O(6); one O(8,11); and one O(9) atom. The Ce(3)-O(1,12) bond length is 2.32 Å. The Ce(3)-O(10) bond length is 2.37 Å. The Ce(3)-O(2) bond length is 2.32 Å. The Ce(3)-O(3) bond length is 2.38 Å. The Ce(3)-O(4) bond length is 2.37 Å. The Ce(3)-O(6) bond length is 2.32 Å. The Ce(3)-O(8,11) bond length is 2.32 Å. The Ce(3)-O(9) bond length is 2.32 Å. In the fourth Ce site, Ce(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(2); one O(3); one O(4); one O(6); one O(8,11); and one O(9) atom. The Ce(3)-O(1,12) bond length is 2.32 Å. The Ce(3)-O(10) bond length is 2.37 Å. The Ce(3)-O(2) bond length is 2.32 Å. The Ce(3)-O(3) bond length is 2.38 Å. The Ce(3)-O(4) bond length is 2.37 Å. The Ce(3)-O(6) bond length is 2.32 Å. The Ce(3)-O(8,11) bond length is 2.32 Å. The Ce(3)-O(9) bond length is 2.32 Å. In the fifth Ce site, Ce(3) is bonded in a body-centered cubic geometry to one O(1,12); one O(10); one O(2); one O(3); one O(4); one O(6); one O(8,11); and one O(9) atom. The Ce(3)-O(1,12) bond length is 2.32 Å. The Ce(3)-O(10) bond length is 2.37 Å. The Ce(3)-O(2) bond length is 2.32 Å. The Ce(3)-O(3) bond length is 2.38 Å. The Ce(3)-O(4) bond length is 2.37 Å. The Ce(3)-O(6) bond length is 2.32 Å. The Ce(3)-O(8,11) bond length is 2.32 Å. The Ce(3)-O(9) bond length is 2.32 Å. There are sixteen inequivalent O sites. In the first O site, O(1,12) is bonded to one Tb(1); one Tb(2); and two Ce(3,3) atoms to form OTb2Ce2 tetrahedra that share corners with two equivalent O(4)Ce4 tetrahedra; corners with two equivalent O(5)Tb4 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; and edges with two equivalent O(3)Tb2Ce2 tetrahedra. In the second O site, O(2) is bonded to one Tb(2), one Tb(3), one Ce(2), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(10,10)Ce4 tetrahedra; corners with two equivalent O(2)Tb2Ce2 tetrahedra; corners with two equivalent O(3)Tb2Ce2 tetrahedra; corners with two equivalent O(7)Tb4 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(4)Ce4 tetrahedra;  an edgeedge with one O(6)Tb2Ce2 tetrahedra;  an edgeedge with one O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(5)Tb4 tetrahedra; and edges with two equivalent O(1,12)Tb2Ce2 tetrahedra. In the third O site, O(3) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(10,10)Ce4 tetrahedra; corners with two equivalent O(2)Tb2Ce2 tetrahedra; corners with two equivalent O(3)Tb2Ce2 tetrahedra; corners with two equivalent O(7)Tb4 tetrahedra; corners with four equivalent O(6)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra;  an edgeedge with one O(4)Ce4 tetrahedra;  an edgeedge with one O(6)Tb2Ce2 tetrahedra;  an edgeedge with one O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(5)Tb4 tetrahedra; and edges with two equivalent O(1,12)Tb2Ce2 tetrahedra. The O(3)-Ce(1) bond length is 2.38 Å. In the fourth O site, O(4) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with four O(10,10)Ce4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; edges with two equivalent O(3)Tb2Ce2 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the fifth O site, O(5) is bonded to one Tb(1), one Tb(2), and two equivalent Tb(3) atoms to form OTb4 tetrahedra that share corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra; corners with four equivalent O(7)Tb4 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; edges with two equivalent O(3)Tb2Ce2 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. The O(5)-Tb(2) bond length is 2.37 Å. In the sixth O site, O(6) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(4,4)Ce4 tetrahedra; corners with two equivalent O(6)Tb2Ce2 tetrahedra; corners with two equivalent O(9)Tb2Ce2 tetrahedra; corners with two O(5,5)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(3)Tb2Ce2 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. The O(6)-Tb(1) bond length is 2.42 Å. In the seventh O site, O(6) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(4,4)Ce4 tetrahedra; corners with two equivalent O(6)Tb2Ce2 tetrahedra; corners with two equivalent O(9)Tb2Ce2 tetrahedra; corners with two O(5,5)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(3)Tb2Ce2 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. The O(6)-Tb(3) bond length is 2.42 Å. In the eighth O site, O(7) is bonded to one Tb(1), one Tb(2), and two equivalent Tb(3) atoms to form OTb4 tetrahedra that share corners with four equivalent O(2)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; corners with four O(5,5)Tb4 tetrahedra; edges with two equivalent O(1,12)Tb2Ce2 tetrahedra; edges with two O(6,6)Tb2Ce2 tetrahedra; and edges with two equivalent O(9)Tb2Ce2 tetrahedra. In the ninth O site, O(8,11) is bonded to one Tb(1), one Tb(2), and two equivalent Ce(3) atoms to form OTb2Ce2 tetrahedra that share corners with two equivalent O(10)Ce4 tetrahedra; corners with two equivalent O(7)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four equivalent O(2)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra;  an edgeedge with one O(4)Ce4 tetrahedra;  an edgeedge with one O(5)Tb4 tetrahedra; edges with two O(6,6)Tb2Ce2 tetrahedra; and edges with two equivalent O(9)Tb2Ce2 tetrahedra. In the tenth O site, O(9) is bonded to one Tb(2), one Tb(3), one Ce(2), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(4,4)Ce4 tetrahedra; corners with two equivalent O(6)Tb2Ce2 tetrahedra; corners with two equivalent O(9)Tb2Ce2 tetrahedra; corners with two O(5,5)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four equivalent O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(3)Tb2Ce2 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. In the eleventh O site, O(10) is bonded to one Ce(1); one Ce(2); and two Ce(3,3) atoms to form OCe4 tetrahedra that share corners with four O(4,4)Ce4 tetrahedra; corners with four equivalent O(2)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; edges with two equivalent O(1,12)Tb2Ce2 tetrahedra; edges with two O(6,6)Tb2Ce2 tetrahedra; and edges with two equivalent O(9)Tb2Ce2 tetrahedra. In the twelfth O site, O(3) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(10,10)Ce4 tetrahedra; corners with two equivalent O(2)Tb2Ce2 tetrahedra; corners with two equivalent O(3)Tb2Ce2 tetrahedra; corners with two equivalent O(7)Tb4 tetrahedra; corners with four equivalent O(6)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra;  an edgeedge with one O(4)Ce4 tetrahedra;  an edgeedge with one O(6)Tb2Ce2 tetrahedra;  an edgeedge with one O(9)Tb2Ce2 tetrahedra;  an edgeedge with one O(5)Tb4 tetrahedra; and edges with two equivalent O(1,12)Tb2Ce2 tetrahedra. The O(3)-Tb(1) bond length is 2.36 Å. In the thirteenth O site, O(4) is bonded to one Ce(1); one Ce(2); and two Ce(3,3) atoms to form OCe4 tetrahedra that share corners with four O(10,10)Ce4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; edges with two equivalent O(3)Tb2Ce2 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. The O(4)-Ce(1) bond length is 2.37 Å. The O(4)-Ce(2) bond length is 2.37 Å. In the fourteenth O site, O(5) is bonded to one Tb(1), one Tb(2), and two equivalent Tb(3) atoms to form OTb4 tetrahedra that share corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(6,6,6)Tb2Ce2 tetrahedra; corners with four equivalent O(9)Tb2Ce2 tetrahedra; corners with four equivalent O(7)Tb4 tetrahedra; edges with two equivalent O(2)Tb2Ce2 tetrahedra; edges with two equivalent O(3)Tb2Ce2 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. The O(5)-Tb(1) bond length is 2.37 Å. In the fifteenth O site, O(6) is bonded to one Tb(1), one Tb(3), one Ce(1), and one Ce(3) atom to form OTb2Ce2 tetrahedra that share corners with two O(4,4)Ce4 tetrahedra; corners with two equivalent O(6)Tb2Ce2 tetrahedra; corners with two equivalent O(9)Tb2Ce2 tetrahedra; corners with two O(5,5)Tb4 tetrahedra; corners with four equivalent O(1,12)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra;  an edgeedge with one O(10)Ce4 tetrahedra;  an edgeedge with one O(2)Tb2Ce2 tetrahedra;  an edgeedge with one O(3)Tb2Ce2 tetrahedra;  an edgeedge with one O(7)Tb4 tetrahedra; and edges with two equivalent O(8,11)Tb2Ce2 tetrahedra. The O(6)-Tb(3) bond length is 2.42 Å. The O(6)-Ce(1) bond length is 2.32 Å. The O(6)-Ce(3) bond length is 2.32 Å. In the sixteenth O site, O(10) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with four O(4,4)Ce4 tetrahedra; corners with four equivalent O(2)Tb2Ce2 tetrahedra; corners with four O(3,3)Tb2Ce2 tetrahedra; corners with four equivalent O(8,11)Tb2Ce2 tetrahedra; edges with two equivalent O(1,12)Tb2Ce2 tetrahedra; edges with two O(6,6)Tb2Ce2 tetrahedra; and edges with two equivalent O(9)Tb2Ce2 tetrahedra. The O(10)-Ce(1) bond length is 2.37 Å. The O(10)-Ce(2) bond length is 2.37 Å.