Ti5O9 crystallizes in the triclinic P-1 space group. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(3), one O(4), one O(9), and two equivalent O(1) atoms to form a mixture of distorted face, corner, and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. In the second Ti site, Ti(2) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(3) atoms to form a mixture of distorted face, corner, and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. In the third Ti site, Ti(3) is bonded to one O(1), one O(4), one O(5), one O(6), one O(8), and one O(9) atom to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-61°. In the fourth Ti site, Ti(4) is bonded to one O(2), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-61°. In the fifth Ti site, Ti(5) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. In the sixth Ti site, Ti(6) is bonded to two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ti(2), one Ti(3), and two equivalent Ti(1) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ti(1), one Ti(2), and one Ti(4) atom. In the third O site, O(3) is bonded to one Ti(1), one Ti(4), and two equivalent Ti(2) atoms to form a mixture of corner and edge-sharing OTi4 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ti(1), one Ti(2), one Ti(3), and one Ti(4) atom to form distorted edge-sharing OTi4 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ti(2), one Ti(3), and one Ti(5) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ti(3), one Ti(4), and one Ti(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ti(4), one Ti(5), and one Ti(6) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ti(3), one Ti(4), and one Ti(6) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Ti(1), one Ti(3), and one Ti(6) atom.
Ti5O9 crystallizes in the triclinic P-1 space group. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(3), one O(4), one O(9), and two equivalent O(1) atoms to form a mixture of distorted face, corner, and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. The Ti(1)-O(2) bond length is 1.84 Å. The Ti(1)-O(3) bond length is 2.01 Å. The Ti(1)-O(4) bond length is 2.14 Å. The Ti(1)-O(9) bond length is 1.88 Å. There is one shorter (1.97 Å) and one longer (2.21 Å) Ti(1)-O(1) bond length. In the second Ti site, Ti(2) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(3) atoms to form a mixture of distorted face, corner, and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. The Ti(2)-O(1) bond length is 2.06 Å. The Ti(2)-O(2) bond length is 1.96 Å. The Ti(2)-O(4) bond length is 2.03 Å. The Ti(2)-O(5) bond length is 1.85 Å. There is one shorter (1.99 Å) and one longer (2.17 Å) Ti(2)-O(3) bond length. In the third Ti site, Ti(3) is bonded to one O(1), one O(4), one O(5), one O(6), one O(8), and one O(9) atom to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-61°. The Ti(3)-O(1) bond length is 2.10 Å. The Ti(3)-O(4) bond length is 2.10 Å. The Ti(3)-O(5) bond length is 1.98 Å. The Ti(3)-O(6) bond length is 1.94 Å. The Ti(3)-O(8) bond length is 1.90 Å. The Ti(3)-O(9) bond length is 1.99 Å. In the fourth Ti site, Ti(4) is bonded to one O(2), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-61°. The Ti(4)-O(2) bond length is 2.10 Å. The Ti(4)-O(3) bond length is 2.06 Å. The Ti(4)-O(4) bond length is 2.04 Å. The Ti(4)-O(6) bond length is 1.91 Å. The Ti(4)-O(7) bond length is 1.94 Å. The Ti(4)-O(8) bond length is 1.98 Å. In the fifth Ti site, Ti(5) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. Both Ti(5)-O(5) bond lengths are 2.01 Å. Both Ti(5)-O(6) bond lengths are 2.01 Å. Both Ti(5)-O(7) bond lengths are 1.97 Å. In the sixth Ti site, Ti(6) is bonded to two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. Both Ti(6)-O(7) bond lengths are 1.96 Å. Both Ti(6)-O(8) bond lengths are 1.98 Å. Both Ti(6)-O(9) bond lengths are 2.03 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ti(2), one Ti(3), and two equivalent Ti(1) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ti(1), one Ti(2), and one Ti(4) atom. In the third O site, O(3) is bonded to one Ti(1), one Ti(4), and two equivalent Ti(2) atoms to form a mixture of corner and edge-sharing OTi4 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ti(1), one Ti(2), one Ti(3), and one Ti(4) atom to form distorted edge-sharing OTi4 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ti(2), one Ti(3), and one Ti(5) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ti(3), one Ti(4), and one Ti(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ti(4), one Ti(5), and one Ti(6) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ti(3), one Ti(4), and one Ti(6) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Ti(1), one Ti(3), and one Ti(6) atom.