Ce5O9 crystallizes in the triclinic P-1 space group. 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), one O(2), one O(3), one O(6), one O(8), one O(9), and two equivalent O(7) atoms. In the second Ce site, Ce(2) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and two equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing CeO7 pentagonal bipyramids. In the third Ce site, Ce(3) is bonded in a 7-coordinate geometry to one O(5), one O(6), one O(9), two equivalent O(2), and two equivalent O(8) atoms. In the fourth Ce site, Ce(4) is bonded in a 7-coordinate geometry to one O(3), one O(6), one O(7), two equivalent O(4), and two equivalent O(9) atoms. In the fifth Ce site, Ce(5) is bonded to one O(4), one O(6), one O(8), two equivalent O(1), and two equivalent O(5) atoms to form a mixture of distorted corner and edge-sharing CeO7 pentagonal bipyramids. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(5) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the second O site, O(2) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the third O site, O(3) is bonded to one Ce(1), one Ce(4), and two equivalent Ce(2) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the fourth O site, O(4) is bonded to one Ce(2), one Ce(5), and two equivalent Ce(4) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the fifth O site, O(5) is bonded to one Ce(2), one Ce(3), and two equivalent Ce(5) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the sixth O site, O(6) is bonded to one Ce(1), one Ce(3), one Ce(4), and one Ce(5) atom to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the seventh O site, O(7) is bonded to one Ce(2), one Ce(4), and two equivalent Ce(1) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the eighth O site, O(8) is bonded to one Ce(1), one Ce(5), and two equivalent Ce(3) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the ninth O site, O(9) is bonded to one Ce(1), one Ce(3), and two equivalent Ce(4) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra.
Ce5O9 crystallizes in the triclinic P-1 space group. 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), one O(2), one O(3), one O(6), one O(8), one O(9), and two equivalent O(7) atoms. The Ce(1)-O(1) bond length is 2.54 Å. The Ce(1)-O(2) bond length is 2.53 Å. The Ce(1)-O(3) bond length is 2.54 Å. The Ce(1)-O(6) bond length is 2.39 Å. The Ce(1)-O(8) bond length is 2.40 Å. The Ce(1)-O(9) bond length is 2.50 Å. There is one shorter (2.32 Å) and one longer (2.40 Å) Ce(1)-O(7) bond length. In the second Ce site, Ce(2) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and two equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing CeO7 pentagonal bipyramids. The Ce(2)-O(1) bond length is 2.32 Å. The Ce(2)-O(2) bond length is 2.30 Å. The Ce(2)-O(4) bond length is 2.38 Å. The Ce(2)-O(5) bond length is 2.36 Å. The Ce(2)-O(7) bond length is 2.33 Å. Both Ce(2)-O(3) bond lengths are 2.40 Å. In the third Ce site, Ce(3) is bonded in a 7-coordinate geometry to one O(5), one O(6), one O(9), two equivalent O(2), and two equivalent O(8) atoms. The Ce(3)-O(5) bond length is 2.28 Å. The Ce(3)-O(6) bond length is 2.31 Å. The Ce(3)-O(9) bond length is 2.31 Å. There is one shorter (2.34 Å) and one longer (2.41 Å) Ce(3)-O(2) bond length. There is one shorter (2.30 Å) and one longer (2.58 Å) Ce(3)-O(8) bond length. In the fourth Ce site, Ce(4) is bonded in a 7-coordinate geometry to one O(3), one O(6), one O(7), two equivalent O(4), and two equivalent O(9) atoms. The Ce(4)-O(3) bond length is 2.28 Å. The Ce(4)-O(6) bond length is 2.30 Å. The Ce(4)-O(7) bond length is 2.28 Å. There is one shorter (2.35 Å) and one longer (2.50 Å) Ce(4)-O(4) bond length. There is one shorter (2.34 Å) and one longer (2.48 Å) Ce(4)-O(9) bond length. In the fifth Ce site, Ce(5) is bonded to one O(4), one O(6), one O(8), two equivalent O(1), and two equivalent O(5) atoms to form a mixture of distorted corner and edge-sharing CeO7 pentagonal bipyramids. The Ce(5)-O(4) bond length is 2.33 Å. The Ce(5)-O(6) bond length is 2.30 Å. The Ce(5)-O(8) bond length is 2.32 Å. There is one shorter (2.32 Å) and one longer (2.41 Å) Ce(5)-O(1) bond length. There is one shorter (2.29 Å) and one longer (2.34 Å) Ce(5)-O(5) bond length. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(5) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the second O site, O(2) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the third O site, O(3) is bonded to one Ce(1), one Ce(4), and two equivalent Ce(2) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the fourth O site, O(4) is bonded to one Ce(2), one Ce(5), and two equivalent Ce(4) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the fifth O site, O(5) is bonded to one Ce(2), one Ce(3), and two equivalent Ce(5) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the sixth O site, O(6) is bonded to one Ce(1), one Ce(3), one Ce(4), and one Ce(5) atom to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the seventh O site, O(7) is bonded to one Ce(2), one Ce(4), and two equivalent Ce(1) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the eighth O site, O(8) is bonded to one Ce(1), one Ce(5), and two equivalent Ce(3) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the ninth O site, O(9) is bonded to one Ce(1), one Ce(3), and two equivalent Ce(4) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra.