The material structure described by TiNb2O7 crystallizes in the monoclinic Cm space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one O(1), one O(15), one O(17), one O(5), and two equivalent O(12) atoms. In the second Ti site, Ti(2) is bonded to one O(16), one O(18), one O(2), one O(6), and two equivalent O(11) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Nb(6)O6 octahedra and corners with two equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-32°. In the third Ti site, Ti(3) is bonded to one O(13), one O(17), one O(7), one O(9), and two equivalent O(14) atoms to form TiO6 octahedra that share  a cornercorner with one Nb(5)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, and edges with two equivalent Nb(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-26°. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one O(11), one O(19), one O(20), one O(7), and two equivalent O(6) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(12), one O(19), one O(20), one O(8), and two equivalent O(5) atoms. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one O(11), one O(15), one O(19), one O(3), and two equivalent O(2) atoms. In the fourth Nb site, Nb(4) is bonded in a 6-coordinate geometry to one O(12), one O(16), one O(20), one O(4), and two equivalent O(1) atoms. In the fifth Nb site, Nb(5) is bonded to one O(10), one O(3), one O(4), one O(9), and two equivalent O(21) atoms to form NbO6 octahedra that share  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Nb(6)O6 octahedra, and corners with two equivalent Nb(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-11°. In the sixth Nb site, Nb(6) is bonded to one O(10), one O(14), one O(18), one O(8), and two equivalent O(13) atoms to form NbO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Nb(5)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra, and edges with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-30°. There are twenty-one inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ti(1) and two equivalent Nb(4) atoms. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Ti(2) and two equivalent Nb(3) atoms. In the third O site, O(3) is bonded in a linear geometry to one Nb(3) and one Nb(5) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Nb(4) and one Nb(5) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ti(1) and two equivalent Nb(2) atoms. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Ti(2) and two equivalent Nb(1) atoms. In the seventh O site, O(7) is bonded in a linear geometry to one Ti(3) and one Nb(1) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Nb(2) and one Nb(6) atom. In the ninth O site, O(9) is bonded in a linear geometry to one Ti(3) and one Nb(5) atom. In the tenth O site, O(10) is bonded in a linear geometry to one Nb(5) and one Nb(6) atom. In the eleventh O site, O(11) is bonded to two equivalent Ti(2), one Nb(1), and one Nb(3) atom to form distorted corner-sharing OTi2Nb2 tetrahedra. In the twelfth O site, O(12) is bonded to two equivalent Ti(1), one Nb(2), and one Nb(4) atom to form distorted corner-sharing OTi2Nb2 tetrahedra. In the thirteenth O site, O(13) is bonded in a distorted trigonal non-coplanar geometry to one Ti(3) and two equivalent Nb(6) atoms. In the fourteenth O site, O(14) is bonded in a distorted T-shaped geometry to two equivalent Ti(3) and one Nb(6) atom. In the fifteenth O site, O(15) is bonded in a linear geometry to one Ti(1) and one Nb(3) atom. In the sixteenth O site, O(16) is bonded in a linear geometry to one Ti(2) and one Nb(4) atom. In the seventeenth O site, O(17) is bonded in a linear geometry to one Ti(1) and one Ti(3) atom. In the eighteenth O site, O(18) is bonded in a linear geometry to one Ti(2) and one Nb(6) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the twentieth O site, O(20) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Nb(4) atom. In the twenty-first O site, O(21) is bonded in a linear geometry to two equivalent Nb(5) atoms. is represented by the CIF file [CIF]
data_TiNb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.424
_cell_length_b   10.424
_cell_length_c   12.074
_cell_angle_alpha   60.326
_cell_angle_beta   60.326
_cell_angle_gamma   21.193
_symmetry_Int_Tables_number   1
_cell_volume   409.720
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ti  Ti0  1  0.707  0.707  0.363  1.0
  Ti  Ti1  1  0.295  0.295  0.630  1.0
  Ti  Ti2  1  0.809  0.809  0.015  1.0
  Nb  Nb3  1  0.919  0.919  0.646  1.0
  Nb  Nb4  1  0.080  0.080  0.361  1.0
  Nb  Nb5  1  0.887  0.887  0.370  1.0
  Nb  Nb6  1  0.114  0.114  0.628  1.0
  Nb  Nb7  1  0.995  0.995  1.000  1.0
  Nb  Nb8  1  0.189  0.189  0.986  1.0
  O  O9  1  0.628  0.628  0.577  1.0
  O  O10  1  0.372  0.372  0.423  1.0
  O  O11  1  0.950  0.950  0.197  1.0
  O  O12  1  0.050  0.050  0.801  1.0
  O  O13  1  0.598  0.598  0.379  1.0
  O  O14  1  0.402  0.402  0.622  1.0
  O  O15  1  0.873  0.873  0.817  1.0
  O  O16  1  0.125  0.125  0.187  1.0
  O  O17  1  0.898  0.898  0.015  1.0
  O  O18  1  0.101  0.101  0.985  1.0
  O  O19  1  0.826  0.826  0.598  1.0
  O  O20  1  0.174  0.174  0.402  1.0
  O  O21  1  0.710  0.710  0.998  1.0
  O  O22  1  0.291  0.291  0.006  1.0
  O  O23  1  0.790  0.790  0.384  1.0
  O  O24  1  0.211  0.211  0.615  1.0
  O  O25  1  0.750  0.750  0.196  1.0
  O  O26  1  0.252  0.252  0.800  1.0
  O  O27  1  0.975  0.975  0.417  1.0
  O  O28  1  0.025  0.025  0.584  1.0
  O  O29  1  0.504  0.504  0.998  1.0
[/CIF]
.
The material structure described by TiNb2O7 crystallizes in the monoclinic Cm space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to one O(1), one O(15), one O(17), one O(5), and two equivalent O(12) atoms. In the second Ti site, Ti(2) is bonded to one O(16), one O(18), one O(2), one O(6), and two equivalent O(11) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Nb(6)O6 octahedra and corners with two equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-32°. In the third Ti site, Ti(3) is bonded to one O(13), one O(17), one O(7), one O(9), and two equivalent O(14) atoms to form TiO6 octahedra that share  a cornercorner with one Nb(5)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, and edges with two equivalent Nb(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-26°. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one O(11), one O(19), one O(20), one O(7), and two equivalent O(6) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(12), one O(19), one O(20), one O(8), and two equivalent O(5) atoms. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one O(11), one O(15), one O(19), one O(3), and two equivalent O(2) atoms. In the fourth Nb site, Nb(4) is bonded in a 6-coordinate geometry to one O(12), one O(16), one O(20), one O(4), and two equivalent O(1) atoms. In the fifth Nb site, Nb(5) is bonded to one O(10), one O(3), one O(4), one O(9), and two equivalent O(21) atoms to form NbO6 octahedra that share  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Nb(6)O6 octahedra, and corners with two equivalent Nb(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-11°. In the sixth Nb site, Nb(6) is bonded to one O(10), one O(14), one O(18), one O(8), and two equivalent O(13) atoms to form NbO6 octahedra that share  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Nb(5)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra, and edges with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-30°. There are twenty-one inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ti(1) and two equivalent Nb(4) atoms. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Ti(2) and two equivalent Nb(3) atoms. In the third O site, O(3) is bonded in a linear geometry to one Nb(3) and one Nb(5) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Nb(4) and one Nb(5) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ti(1) and two equivalent Nb(2) atoms. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Ti(2) and two equivalent Nb(1) atoms. In the seventh O site, O(7) is bonded in a linear geometry to one Ti(3) and one Nb(1) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Nb(2) and one Nb(6) atom. In the ninth O site, O(9) is bonded in a linear geometry to one Ti(3) and one Nb(5) atom. In the tenth O site, O(10) is bonded in a linear geometry to one Nb(5) and one Nb(6) atom. In the eleventh O site, O(11) is bonded to two equivalent Ti(2), one Nb(1), and one Nb(3) atom to form distorted corner-sharing OTi2Nb2 tetrahedra. In the twelfth O site, O(12) is bonded to two equivalent Ti(1), one Nb(2), and one Nb(4) atom to form distorted corner-sharing OTi2Nb2 tetrahedra. In the thirteenth O site, O(13) is bonded in a distorted trigonal non-coplanar geometry to one Ti(3) and two equivalent Nb(6) atoms. In the fourteenth O site, O(14) is bonded in a distorted T-shaped geometry to two equivalent Ti(3) and one Nb(6) atom. In the fifteenth O site, O(15) is bonded in a linear geometry to one Ti(1) and one Nb(3) atom. In the sixteenth O site, O(16) is bonded in a linear geometry to one Ti(2) and one Nb(4) atom. In the seventeenth O site, O(17) is bonded in a linear geometry to one Ti(1) and one Ti(3) atom. In the eighteenth O site, O(18) is bonded in a linear geometry to one Ti(2) and one Nb(6) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the twentieth O site, O(20) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Nb(4) atom. In the twenty-first O site, O(21) is bonded in a linear geometry to two equivalent Nb(5) atoms. is represented by the CIF file [CIF]
data_TiNb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.424
_cell_length_b   10.424
_cell_length_c   12.074
_cell_angle_alpha   60.326
_cell_angle_beta   60.326
_cell_angle_gamma   21.193
_symmetry_Int_Tables_number   1
_cell_volume   409.720
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ti  Ti0  1  0.707  0.707  0.363  1.0
  Ti  Ti1  1  0.295  0.295  0.630  1.0
  Ti  Ti2  1  0.809  0.809  0.015  1.0
  Nb  Nb3  1  0.919  0.919  0.646  1.0
  Nb  Nb4  1  0.080  0.080  0.361  1.0
  Nb  Nb5  1  0.887  0.887  0.370  1.0
  Nb  Nb6  1  0.114  0.114  0.628  1.0
  Nb  Nb7  1  0.995  0.995  1.000  1.0
  Nb  Nb8  1  0.189  0.189  0.986  1.0
  O  O9  1  0.628  0.628  0.577  1.0
  O  O10  1  0.372  0.372  0.423  1.0
  O  O11  1  0.950  0.950  0.197  1.0
  O  O12  1  0.050  0.050  0.801  1.0
  O  O13  1  0.598  0.598  0.379  1.0
  O  O14  1  0.402  0.402  0.622  1.0
  O  O15  1  0.873  0.873  0.817  1.0
  O  O16  1  0.125  0.125  0.187  1.0
  O  O17  1  0.898  0.898  0.015  1.0
  O  O18  1  0.101  0.101  0.985  1.0
  O  O19  1  0.826  0.826  0.598  1.0
  O  O20  1  0.174  0.174  0.402  1.0
  O  O21  1  0.710  0.710  0.998  1.0
  O  O22  1  0.291  0.291  0.006  1.0
  O  O23  1  0.790  0.790  0.384  1.0
  O  O24  1  0.211  0.211  0.615  1.0
  O  O25  1  0.750  0.750  0.196  1.0
  O  O26  1  0.252  0.252  0.800  1.0
  O  O27  1  0.975  0.975  0.417  1.0
  O  O28  1  0.025  0.025  0.584  1.0
  O  O29  1  0.504  0.504  0.998  1.0
[/CIF]
.