H2Ti3O7 crystallizes in the monoclinic Cm space group. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one O(1), one O(11), one O(3), one O(9), and two equivalent O(14) atoms. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(2), one O(4), and two equivalent O(13) atoms. In the third Ti site, Ti(3) is bonded to one O(11), one O(13), one O(3), one O(5), and two equivalent O(12) atoms to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 34°. In the fourth Ti site, Ti(4) is bonded to one O(12), one O(14), one O(4), one O(6), and two equivalent O(11) atoms to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 31°. In the fifth Ti site, Ti(5) is bonded to one O(1), one O(13), one O(5), one O(7), and two equivalent O(10) atoms to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 34°. In the sixth Ti site, Ti(6) is bonded in a 5-coordinate geometry to one O(2), one O(6), one O(8), and two equivalent O(9) atoms. There are four inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(3) and one O(8) atom. In the second H site, H(2) is bonded in a linear geometry to one O(4) and one O(7) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(7) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(9) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Ti(1) and one Ti(5) atom. In the second O site, O(2) is bonded in a linear geometry to one Ti(2) and one Ti(6) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Ti(1), one Ti(3), and one H(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Ti(2), one Ti(4), and one H(2) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one Ti(3) and one Ti(5) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Ti(4) and one Ti(6) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ti(5), one H(2), and one H(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ti(6) and one H(1) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one Ti(1), two equivalent Ti(6), and one H(4) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Ti(2) and two equivalent Ti(5) atoms. In the eleventh O site, O(11) is bonded to one Ti(1), one Ti(3), and two equivalent Ti(4) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the twelfth O site, O(12) is bonded to one Ti(2), one Ti(4), and two equivalent Ti(3) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the thirteenth O site, O(13) is bonded to one Ti(3), one Ti(5), and two equivalent Ti(2) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Ti(4) and two equivalent Ti(1) atoms.
H2Ti3O7 crystallizes in the monoclinic Cm space group. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one O(1), one O(11), one O(3), one O(9), and two equivalent O(14) atoms. The Ti(1)-O(1) bond length is 1.75 Å. The Ti(1)-O(11) bond length is 2.20 Å. The Ti(1)-O(3) bond length is 1.91 Å. The Ti(1)-O(9) bond length is 2.28 Å. Both Ti(1)-O(14) bond lengths are 1.98 Å. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(2), one O(4), and two equivalent O(13) atoms. The Ti(2)-O(10) bond length is 2.02 Å. The Ti(2)-O(12) bond length is 2.25 Å. The Ti(2)-O(2) bond length is 1.76 Å. The Ti(2)-O(4) bond length is 2.03 Å. Both Ti(2)-O(13) bond lengths are 1.96 Å. In the third Ti site, Ti(3) is bonded to one O(11), one O(13), one O(3), one O(5), and two equivalent O(12) atoms to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 34°. The Ti(3)-O(11) bond length is 2.30 Å. The Ti(3)-O(13) bond length is 2.12 Å. The Ti(3)-O(3) bond length is 1.95 Å. The Ti(3)-O(5) bond length is 1.76 Å. Both Ti(3)-O(12) bond lengths are 1.98 Å. In the fourth Ti site, Ti(4) is bonded to one O(12), one O(14), one O(4), one O(6), and two equivalent O(11) atoms to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 31°. The Ti(4)-O(12) bond length is 2.23 Å. The Ti(4)-O(14) bond length is 2.09 Å. The Ti(4)-O(4) bond length is 1.94 Å. The Ti(4)-O(6) bond length is 1.80 Å. Both Ti(4)-O(11) bond lengths are 1.97 Å. In the fifth Ti site, Ti(5) is bonded to one O(1), one O(13), one O(5), one O(7), and two equivalent O(10) atoms to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 34°. The Ti(5)-O(1) bond length is 1.96 Å. The Ti(5)-O(13) bond length is 2.32 Å. The Ti(5)-O(5) bond length is 1.95 Å. The Ti(5)-O(7) bond length is 1.85 Å. Both Ti(5)-O(10) bond lengths are 1.98 Å. In the sixth Ti site, Ti(6) is bonded in a 5-coordinate geometry to one O(2), one O(6), one O(8), and two equivalent O(9) atoms. The Ti(6)-O(2) bond length is 2.02 Å. The Ti(6)-O(6) bond length is 1.88 Å. The Ti(6)-O(8) bond length is 1.73 Å. Both Ti(6)-O(9) bond lengths are 2.04 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(3) and one O(8) atom. The H(1)-O(3) bond length is 1.12 Å. The H(1)-O(8) bond length is 1.31 Å. In the second H site, H(2) is bonded in a linear geometry to one O(4) and one O(7) atom. The H(2)-O(4) bond length is 1.03 Å. The H(2)-O(7) bond length is 1.55 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(7) atom. The H(3)-O(7) bond length is 1.01 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(9) atom. The H(4)-O(9) bond length is 0.99 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Ti(1) and one Ti(5) atom. In the second O site, O(2) is bonded in a linear geometry to one Ti(2) and one Ti(6) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Ti(1), one Ti(3), and one H(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Ti(2), one Ti(4), and one H(2) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one Ti(3) and one Ti(5) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Ti(4) and one Ti(6) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ti(5), one H(2), and one H(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ti(6) and one H(1) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one Ti(1), two equivalent Ti(6), and one H(4) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Ti(2) and two equivalent Ti(5) atoms. In the eleventh O site, O(11) is bonded to one Ti(1), one Ti(3), and two equivalent Ti(4) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the twelfth O site, O(12) is bonded to one Ti(2), one Ti(4), and two equivalent Ti(3) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the thirteenth O site, O(13) is bonded to one Ti(3), one Ti(5), and two equivalent Ti(2) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Ti(4) and two equivalent Ti(1) atoms.