Ti9O8 crystallizes in the triclinic P-1 space group. There are nine inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(8) atom to form TiO6 octahedra that share  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(9)O6 octahedra,  a cornercorner with one Ti(3)O5 square pyramid,  an edgeedge with one Ti(4)O6 octahedra,  an edgeedge with one Ti(9)O6 octahedra,  an edgeedge with one Ti(5)O5 square pyramid,  an edgeedge with one Ti(6)O5 square pyramid,  an edgeedge with one Ti(8)O5 square pyramid, edges with two equivalent Ti(2)O5 square pyramids, edges with two equivalent Ti(3)O5 square pyramids, and edges with three equivalent Ti(7)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-16°. In the second Ti site, Ti(2) is bonded to one O(1), one O(2), one O(6), and two equivalent O(3) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(2)O5 square pyramid,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(7)O5 square pyramids, corners with three equivalent Ti(6)O5 square pyramids, edges with two equivalent Ti(1)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra,  an edgeedge with one Ti(2)O5 square pyramid,  an edgeedge with one Ti(7)O5 square pyramid, and edges with two equivalent Ti(3)O5 square pyramids. In the third Ti site, Ti(3) is bonded to one O(3), one O(4), one O(6), and two equivalent O(1) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(1)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  a cornercorner with one Ti(2)O5 square pyramid,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(6)O5 square pyramid,  a cornercorner with one Ti(7)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid,  an edgeedge with one Ti(4)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra,  an edgeedge with one Ti(3)O5 square pyramid,  an edgeedge with one Ti(6)O5 square pyramid,  an edgeedge with one Ti(7)O5 square pyramid, and edges with two equivalent Ti(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 9-10°. In the fourth Ti site, Ti(4) is bonded to one O(1), one O(3), one O(5), one O(6), one O(7), and one O(9) atom to form TiO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(3)O5 square pyramids, corners with two equivalent Ti(5)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(3)O5 square pyramid,  an edgeedge with one Ti(5)O5 square pyramid,  an edgeedge with one Ti(7)O5 square pyramid, edges with two equivalent Ti(2)O5 square pyramids, edges with two equivalent Ti(6)O5 square pyramids, and edges with two equivalent Ti(8)O5 square pyramids. The corner-sharing octahedral tilt angles are 5°. In the fifth Ti site, Ti(5) is bonded to one O(6), one O(8), one O(9), and two equivalent O(7) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(9)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  a cornercorner with one Ti(2)O5 square pyramid,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(7)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(6)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(5)O5 square pyramid,  an edgeedge with one Ti(6)O5 square pyramid, and edges with two equivalent Ti(8)O5 square pyramids. The corner-sharing octahedral tilt angles range from 6-10°. In the sixth Ti site, Ti(6) is bonded to one O(1), one O(3), one O(7), one O(8), and one O(9) atom to form TiO5 square pyramids that share  a cornercorner with one Ti(3)O5 square pyramid, corners with two equivalent Ti(5)O5 square pyramids, corners with three equivalent Ti(2)O5 square pyramids, corners with three equivalent Ti(8)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(3)O5 square pyramid,  an edgeedge with one Ti(5)O5 square pyramid, and  an edgeedge with one Ti(7)O5 square pyramid. In the seventh Ti site, Ti(7) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form TiO5 square pyramids that share corners with two equivalent Ti(9)O6 octahedra,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(2)O5 square pyramids, corners with two equivalent Ti(7)O5 square pyramids,  an edgeedge with one Ti(4)O6 octahedra,  an edgeedge with one Ti(9)O6 octahedra, edges with three equivalent Ti(1)O6 octahedra,  an edgeedge with one Ti(2)O5 square pyramid,  an edgeedge with one Ti(3)O5 square pyramid, and  an edgeedge with one Ti(6)O5 square pyramid. The corner-sharing octahedral tilt angles range from 7-14°. In the eighth Ti site, Ti(8) is bonded to one O(5), one O(6), one O(7), and two equivalent O(9) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(4)O6 octahedra,  a cornercorner with one Ti(9)O6 octahedra,  a cornercorner with one Ti(2)O5 square pyramid,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(7)O5 square pyramid, corners with three equivalent Ti(6)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(8)O5 square pyramid, and edges with two equivalent Ti(5)O5 square pyramids. The corner-sharing octahedral tilt angles range from 17-18°. In the ninth Ti site, Ti(9) is bonded to one O(7), one O(9), two equivalent O(5), and two equivalent O(8) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(7)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(7)O5 square pyramid, edges with two equivalent Ti(5)O5 square pyramids, edges with two equivalent Ti(6)O5 square pyramids, and edges with two equivalent Ti(8)O5 square pyramids. The corner-sharing octahedral tilt angles range from 8-16°. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ti(1), one Ti(2), one Ti(4), one Ti(6), and two equivalent Ti(3) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. In the second O site, O(2) is bonded to two equivalent Ti(1), two equivalent Ti(2), and two equivalent Ti(7) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. In the third O site, O(3) is bonded to one Ti(3), one Ti(4), one Ti(6), one Ti(7), and two equivalent Ti(2) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 9-12°. In the fourth O site, O(4) is bonded to two equivalent Ti(1), two equivalent Ti(3), and two equivalent Ti(7) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 5-12°. In the fifth O site, O(5) is bonded to one Ti(1), one Ti(4), one Ti(7), one Ti(8), and two equivalent Ti(9) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 5-18°. In the sixth O site, O(6) is bonded to one Ti(1), one Ti(2), one Ti(3), one Ti(4), one Ti(5), and one Ti(8) atom to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 6-16°. In the seventh O site, O(7) is bonded to one Ti(4), one Ti(6), one Ti(8), one Ti(9), and two equivalent Ti(5) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 9-17°. In the eighth O site, O(8) is bonded to one Ti(1), one Ti(5), one Ti(6), one Ti(7), and two equivalent Ti(9) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 6-18°. In the ninth O site, O(9) is bonded to one Ti(4), one Ti(5), one Ti(6), one Ti(9), and two equivalent Ti(8) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 8-17°.
Ti9O8 crystallizes in the triclinic P-1 space group. There are nine inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(8) atom to form TiO6 octahedra that share  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ti(9)O6 octahedra,  a cornercorner with one Ti(3)O5 square pyramid,  an edgeedge with one Ti(4)O6 octahedra,  an edgeedge with one Ti(9)O6 octahedra,  an edgeedge with one Ti(5)O5 square pyramid,  an edgeedge with one Ti(6)O5 square pyramid,  an edgeedge with one Ti(8)O5 square pyramid, edges with two equivalent Ti(2)O5 square pyramids, edges with two equivalent Ti(3)O5 square pyramids, and edges with three equivalent Ti(7)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-16°. The Ti(1)-O(1) bond length is 2.17 Å. The Ti(1)-O(2) bond length is 2.14 Å. The Ti(1)-O(4) bond length is 2.07 Å. The Ti(1)-O(5) bond length is 2.10 Å. The Ti(1)-O(6) bond length is 2.11 Å. The Ti(1)-O(8) bond length is 2.10 Å. In the second Ti site, Ti(2) is bonded to one O(1), one O(2), one O(6), and two equivalent O(3) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(2)O5 square pyramid,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(7)O5 square pyramids, corners with three equivalent Ti(6)O5 square pyramids, edges with two equivalent Ti(1)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra,  an edgeedge with one Ti(2)O5 square pyramid,  an edgeedge with one Ti(7)O5 square pyramid, and edges with two equivalent Ti(3)O5 square pyramids. The Ti(2)-O(1) bond length is 2.15 Å. The Ti(2)-O(2) bond length is 2.15 Å. The Ti(2)-O(6) bond length is 2.13 Å. There is one shorter (2.12 Å) and one longer (2.25 Å) Ti(2)-O(3) bond length. In the third Ti site, Ti(3) is bonded to one O(3), one O(4), one O(6), and two equivalent O(1) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(1)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  a cornercorner with one Ti(2)O5 square pyramid,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(6)O5 square pyramid,  a cornercorner with one Ti(7)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid,  an edgeedge with one Ti(4)O6 octahedra, edges with two equivalent Ti(1)O6 octahedra,  an edgeedge with one Ti(3)O5 square pyramid,  an edgeedge with one Ti(6)O5 square pyramid,  an edgeedge with one Ti(7)O5 square pyramid, and edges with two equivalent Ti(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 9-10°. The Ti(3)-O(3) bond length is 2.25 Å. The Ti(3)-O(4) bond length is 2.13 Å. The Ti(3)-O(6) bond length is 2.17 Å. There is one shorter (2.17 Å) and one longer (2.22 Å) Ti(3)-O(1) bond length. In the fourth Ti site, Ti(4) is bonded to one O(1), one O(3), one O(5), one O(6), one O(7), and one O(9) atom to form TiO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(3)O5 square pyramids, corners with two equivalent Ti(5)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(3)O5 square pyramid,  an edgeedge with one Ti(5)O5 square pyramid,  an edgeedge with one Ti(7)O5 square pyramid, edges with two equivalent Ti(2)O5 square pyramids, edges with two equivalent Ti(6)O5 square pyramids, and edges with two equivalent Ti(8)O5 square pyramids. The corner-sharing octahedral tilt angles are 5°. The Ti(4)-O(1) bond length is 2.24 Å. The Ti(4)-O(3) bond length is 2.12 Å. The Ti(4)-O(5) bond length is 2.10 Å. The Ti(4)-O(6) bond length is 2.12 Å. The Ti(4)-O(7) bond length is 2.19 Å. The Ti(4)-O(9) bond length is 2.14 Å. In the fifth Ti site, Ti(5) is bonded to one O(6), one O(8), one O(9), and two equivalent O(7) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(9)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra,  a cornercorner with one Ti(2)O5 square pyramid,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(7)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(6)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(5)O5 square pyramid,  an edgeedge with one Ti(6)O5 square pyramid, and edges with two equivalent Ti(8)O5 square pyramids. The corner-sharing octahedral tilt angles range from 6-10°. The Ti(5)-O(6) bond length is 2.13 Å. The Ti(5)-O(8) bond length is 2.16 Å. The Ti(5)-O(9) bond length is 2.20 Å. Both Ti(5)-O(7) bond lengths are 2.17 Å. In the sixth Ti site, Ti(6) is bonded to one O(1), one O(3), one O(7), one O(8), and one O(9) atom to form TiO5 square pyramids that share  a cornercorner with one Ti(3)O5 square pyramid, corners with two equivalent Ti(5)O5 square pyramids, corners with three equivalent Ti(2)O5 square pyramids, corners with three equivalent Ti(8)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(3)O5 square pyramid,  an edgeedge with one Ti(5)O5 square pyramid, and  an edgeedge with one Ti(7)O5 square pyramid. The Ti(6)-O(1) bond length is 2.16 Å. The Ti(6)-O(3) bond length is 2.22 Å. The Ti(6)-O(7) bond length is 2.18 Å. The Ti(6)-O(8) bond length is 2.22 Å. The Ti(6)-O(9) bond length is 2.18 Å. In the seventh Ti site, Ti(7) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form TiO5 square pyramids that share corners with two equivalent Ti(9)O6 octahedra,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(2)O5 square pyramids, corners with two equivalent Ti(7)O5 square pyramids,  an edgeedge with one Ti(4)O6 octahedra,  an edgeedge with one Ti(9)O6 octahedra, edges with three equivalent Ti(1)O6 octahedra,  an edgeedge with one Ti(2)O5 square pyramid,  an edgeedge with one Ti(3)O5 square pyramid, and  an edgeedge with one Ti(6)O5 square pyramid. The corner-sharing octahedral tilt angles range from 7-14°. The Ti(7)-O(2) bond length is 2.19 Å. The Ti(7)-O(3) bond length is 2.19 Å. The Ti(7)-O(4) bond length is 2.17 Å. The Ti(7)-O(5) bond length is 2.19 Å. The Ti(7)-O(8) bond length is 2.26 Å. In the eighth Ti site, Ti(8) is bonded to one O(5), one O(6), one O(7), and two equivalent O(9) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(4)O6 octahedra,  a cornercorner with one Ti(9)O6 octahedra,  a cornercorner with one Ti(2)O5 square pyramid,  a cornercorner with one Ti(3)O5 square pyramid,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(7)O5 square pyramid, corners with three equivalent Ti(6)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(8)O5 square pyramid, and edges with two equivalent Ti(5)O5 square pyramids. The corner-sharing octahedral tilt angles range from 17-18°. The Ti(8)-O(5) bond length is 2.15 Å. The Ti(8)-O(6) bond length is 2.19 Å. The Ti(8)-O(7) bond length is 2.18 Å. There is one shorter (2.13 Å) and one longer (2.21 Å) Ti(8)-O(9) bond length. In the ninth Ti site, Ti(9) is bonded to one O(7), one O(9), two equivalent O(5), and two equivalent O(8) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra,  a cornercorner with one Ti(5)O5 square pyramid,  a cornercorner with one Ti(8)O5 square pyramid, corners with two equivalent Ti(7)O5 square pyramids,  an edgeedge with one Ti(1)O6 octahedra, edges with two equivalent Ti(4)O6 octahedra, edges with two equivalent Ti(9)O6 octahedra,  an edgeedge with one Ti(7)O5 square pyramid, edges with two equivalent Ti(5)O5 square pyramids, edges with two equivalent Ti(6)O5 square pyramids, and edges with two equivalent Ti(8)O5 square pyramids. The corner-sharing octahedral tilt angles range from 8-16°. The Ti(9)-O(7) bond length is 2.15 Å. The Ti(9)-O(9) bond length is 2.12 Å. There is one shorter (2.12 Å) and one longer (2.15 Å) Ti(9)-O(5) bond length. There is one shorter (2.08 Å) and one longer (2.21 Å) Ti(9)-O(8) bond length. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Ti(1), one Ti(2), one Ti(4), one Ti(6), and two equivalent Ti(3) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. In the second O site, O(2) is bonded to two equivalent Ti(1), two equivalent Ti(2), and two equivalent Ti(7) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. In the third O site, O(3) is bonded to one Ti(3), one Ti(4), one Ti(6), one Ti(7), and two equivalent Ti(2) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 9-12°. In the fourth O site, O(4) is bonded to two equivalent Ti(1), two equivalent Ti(3), and two equivalent Ti(7) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 5-12°. In the fifth O site, O(5) is bonded to one Ti(1), one Ti(4), one Ti(7), one Ti(8), and two equivalent Ti(9) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 5-18°. In the sixth O site, O(6) is bonded to one Ti(1), one Ti(2), one Ti(3), one Ti(4), one Ti(5), and one Ti(8) atom to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 6-16°. In the seventh O site, O(7) is bonded to one Ti(4), one Ti(6), one Ti(8), one Ti(9), and two equivalent Ti(5) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 9-17°. In the eighth O site, O(8) is bonded to one Ti(1), one Ti(5), one Ti(6), one Ti(7), and two equivalent Ti(9) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 6-18°. In the ninth O site, O(9) is bonded to one Ti(4), one Ti(5), one Ti(6), one Ti(9), and two equivalent Ti(8) atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles range from 8-17°.