NaTi8O16 crystallizes in the monoclinic Cm space group. Na(1) is bonded in a 4-coordinate geometry to one O(10), one O(3), and two equivalent O(5) atoms. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(4), and one O(5) atom to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 44-49°. In the second Ti site, Ti(2) is bonded to one O(2), one O(7), two equivalent O(11), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 47-50°. In the third Ti site, Ti(3) is bonded to one O(3), one O(8), two equivalent O(1), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 44-48°. In the fourth Ti site, Ti(4) is bonded to one O(4), one O(9), two equivalent O(1), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 47-49°. In the fifth Ti site, Ti(5) is bonded to one O(11), one O(12), one O(6), one O(7), 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 46-50°. In the sixth Ti site, Ti(6) is bonded to one O(10), one O(12), two equivalent O(11), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 46-48°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ti(1), one Ti(3), and one Ti(4) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Ti(2) and two equivalent Ti(1) atoms. In the third O site, O(3) is bonded to one Na(1), one Ti(3), and two equivalent Ti(1) atoms to form corner-sharing ONaTi3 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ti(4) and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Na(1), one Ti(1), one Ti(2), and one Ti(6) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Ti(3), one Ti(4), and one Ti(5) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ti(2) and two equivalent Ti(5) atoms. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Ti(3) and two equivalent Ti(5) atoms. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Ti(4) and two equivalent Ti(5) atoms. In the tenth O site, O(10) is bonded to one Na(1), one Ti(6), and two equivalent Ti(1) atoms to form corner-sharing ONaTi3 tetrahedra. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ti(2), one Ti(5), and one Ti(6) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ti(6) and two equivalent Ti(5) atoms.
NaTi8O16 crystallizes in the monoclinic Cm space group. Na(1) is bonded in a 4-coordinate geometry to one O(10), one O(3), and two equivalent O(5) atoms. The Na(1)-O(10) bond length is 2.04 Å. The Na(1)-O(3) bond length is 2.29 Å. Both Na(1)-O(5) bond lengths are 2.19 Å. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(4), and one O(5) atom to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 44-49°. The Ti(1)-O(1) bond length is 1.93 Å. The Ti(1)-O(10) bond length is 1.93 Å. The Ti(1)-O(2) bond length is 1.98 Å. The Ti(1)-O(3) bond length is 2.02 Å. The Ti(1)-O(4) bond length is 2.04 Å. The Ti(1)-O(5) bond length is 2.11 Å. In the second Ti site, Ti(2) is bonded to one O(2), one O(7), two equivalent O(11), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 47-50°. The Ti(2)-O(2) bond length is 2.01 Å. The Ti(2)-O(7) bond length is 2.03 Å. Both Ti(2)-O(11) bond lengths are 1.94 Å. Both Ti(2)-O(5) bond lengths are 2.04 Å. In the third Ti site, Ti(3) is bonded to one O(3), one O(8), two equivalent O(1), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 44-48°. The Ti(3)-O(3) bond length is 2.07 Å. The Ti(3)-O(8) bond length is 1.97 Å. Both Ti(3)-O(1) bond lengths are 2.05 Å. Both Ti(3)-O(6) bond lengths are 1.91 Å. In the fourth Ti site, Ti(4) is bonded to one O(4), one O(9), two equivalent O(1), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 47-49°. The Ti(4)-O(4) bond length is 1.91 Å. The Ti(4)-O(9) bond length is 2.11 Å. Both Ti(4)-O(1) bond lengths are 2.07 Å. Both Ti(4)-O(6) bond lengths are 1.93 Å. In the fifth Ti site, Ti(5) is bonded to one O(11), one O(12), one O(6), one O(7), 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 46-50°. The Ti(5)-O(11) bond length is 1.96 Å. The Ti(5)-O(12) bond length is 2.04 Å. The Ti(5)-O(6) bond length is 2.08 Å. The Ti(5)-O(7) bond length is 2.02 Å. The Ti(5)-O(8) bond length is 1.97 Å. The Ti(5)-O(9) bond length is 1.92 Å. In the sixth Ti site, Ti(6) is bonded to one O(10), one O(12), two equivalent O(11), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 46-48°. The Ti(6)-O(10) bond length is 2.03 Å. The Ti(6)-O(12) bond length is 1.90 Å. Both Ti(6)-O(11) bond lengths are 2.11 Å. Both Ti(6)-O(5) bond lengths are 1.90 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ti(1), one Ti(3), and one Ti(4) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Ti(2) and two equivalent Ti(1) atoms. In the third O site, O(3) is bonded to one Na(1), one Ti(3), and two equivalent Ti(1) atoms to form corner-sharing ONaTi3 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ti(4) and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Na(1), one Ti(1), one Ti(2), and one Ti(6) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Ti(3), one Ti(4), and one Ti(5) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ti(2) and two equivalent Ti(5) atoms. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Ti(3) and two equivalent Ti(5) atoms. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Ti(4) and two equivalent Ti(5) atoms. In the tenth O site, O(10) is bonded to one Na(1), one Ti(6), and two equivalent Ti(1) atoms to form corner-sharing ONaTi3 tetrahedra. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ti(2), one Ti(5), and one Ti(6) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ti(6) and two equivalent Ti(5) atoms.