H2Ti3O7 crystallizes in the triclinic P1 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 in a 6-coordinate geometry to one O(11), one O(13), one O(3), one O(5), and two equivalent O(12) atoms. In the fourth Ti site, Ti(4) is bonded in a 6-coordinate geometry to one O(12), one O(14), one O(4), one O(6), and two equivalent O(11) atoms. 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 distorted corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 19°. In the sixth Ti site, Ti(6) is bonded to one O(14), one O(2), one O(6), one O(8), and two equivalent O(9) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 26°. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(7) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(7) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(8) atom. In the fourth H site, H(4) is bonded in a linear geometry to one O(3) and one O(8) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ti(1) and one Ti(5) atom. In the second O site, O(2) is bonded in a bent 150 degrees 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(4) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Ti(2) and one Ti(4) 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 water-like geometry to one Ti(4) and one Ti(6) atom. In the seventh O site, O(7) is bonded in a distorted L-shaped geometry to one Ti(5), one H(1), and one H(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ti(6), one H(3), and one H(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Ti(1) and two equivalent Ti(6) atoms. In the tenth O site, O(10) is bonded in a T-shaped geometry to one Ti(2) and two equivalent Ti(5) atoms. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Ti(1), one Ti(3), and two equivalent Ti(4) atoms. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Ti(2), one Ti(4), and two equivalent Ti(3) atoms. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Ti(3), one Ti(5), and two equivalent Ti(2) atoms. In the fourteenth O site, O(14) is bonded to one Ti(4), one Ti(6), and two equivalent Ti(1) atoms to form distorted corner-sharing OTi4 trigonal pyramids.
H2Ti3O7 crystallizes in the triclinic P1 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 1.74 Å. The Ti(1)-O(11) bond length is 2.43 Å. The Ti(1)-O(3) bond length is 1.95 Å. The Ti(1)-O(9) bond length is 2.05 Å. Both Ti(1)-O(14) bond lengths are 1.99 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 2.10 Å. The Ti(2)-O(12) bond length is 2.47 Å. The Ti(2)-O(2) bond length is 1.74 Å. The Ti(2)-O(4) bond length is 1.90 Å. Both Ti(2)-O(13) bond lengths are 1.99 Å. In the third Ti site, Ti(3) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(3), one O(5), and two equivalent O(12) atoms. The Ti(3)-O(11) bond length is 2.10 Å. The Ti(3)-O(13) bond length is 2.45 Å. The Ti(3)-O(3) bond length is 1.82 Å. The Ti(3)-O(5) bond length is 1.83 Å. There is one shorter (1.98 Å) and one longer (1.99 Å) Ti(3)-O(12) bond length. In the fourth Ti site, Ti(4) is bonded in a 6-coordinate geometry to one O(12), one O(14), one O(4), one O(6), and two equivalent O(11) atoms. The Ti(4)-O(12) bond length is 2.11 Å. The Ti(4)-O(14) bond length is 2.35 Å. The Ti(4)-O(4) bond length is 1.84 Å. The Ti(4)-O(6) bond length is 1.83 Å. Both Ti(4)-O(11) bond lengths are 1.98 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 distorted corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 19°. The Ti(5)-O(1) bond length is 1.99 Å. The Ti(5)-O(13) bond length is 1.96 Å. The Ti(5)-O(5) bond length is 1.87 Å. The Ti(5)-O(7) bond length is 2.26 Å. There is one shorter (1.89 Å) and one longer (1.96 Å) Ti(5)-O(10) bond length. In the sixth Ti site, Ti(6) is bonded to one O(14), one O(2), one O(6), one O(8), and two equivalent O(9) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 26°. The Ti(6)-O(14) bond length is 2.04 Å. The Ti(6)-O(2) bond length is 2.03 Å. The Ti(6)-O(6) bond length is 1.86 Å. The Ti(6)-O(8) bond length is 2.06 Å. Both Ti(6)-O(9) bond lengths are 1.95 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(7) atom. The H(1)-O(7) bond length is 0.98 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(7) atom. The H(2)-O(7) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(8) atom. The H(3)-O(8) bond length is 0.98 Å. In the fourth H site, H(4) is bonded in a linear geometry to one O(3) and one O(8) atom. The H(4)-O(3) bond length is 1.55 Å. The H(4)-O(8) bond length is 1.03 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ti(1) and one Ti(5) atom. In the second O site, O(2) is bonded in a bent 150 degrees 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(4) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Ti(2) and one Ti(4) 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 water-like geometry to one Ti(4) and one Ti(6) atom. In the seventh O site, O(7) is bonded in a distorted L-shaped geometry to one Ti(5), one H(1), and one H(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ti(6), one H(3), and one H(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Ti(1) and two equivalent Ti(6) atoms. In the tenth O site, O(10) is bonded in a T-shaped geometry to one Ti(2) and two equivalent Ti(5) atoms. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Ti(1), one Ti(3), and two equivalent Ti(4) atoms. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Ti(2), one Ti(4), and two equivalent Ti(3) atoms. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Ti(3), one Ti(5), and two equivalent Ti(2) atoms. In the fourteenth O site, O(14) is bonded to one Ti(4), one Ti(6), and two equivalent Ti(1) atoms to form distorted corner-sharing OTi4 trigonal pyramids.