The material structure described by Na6Ti2O7 crystallizes in the monoclinic Pc space group. There are six inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), one O(6), and one O(7) atom. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and one O(7) atom. In the third Na site, Na(3) is bonded to one O(1), one O(3), one O(4), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Ti(2)O4 tetrahedra, corners with two equivalent Ti(1)O4 tetrahedra,  an edgeedge with one Ti(2)O4 tetrahedra, and edges with two equivalent Na(4)O5 trigonal bipyramids. In the fourth Na site, Na(4) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Ti(1)O4 tetrahedra, corners with two equivalent Ti(2)O4 tetrahedra,  an edgeedge with one Ti(1)O4 tetrahedra, and edges with two equivalent Na(3)O5 trigonal bipyramids. In the fifth Na site, Na(5) is bonded in a 3-coordinate geometry to one O(3), one O(4), and one O(5) atom. In the sixth Na site, Na(6) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(5) atom. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form TiO4 tetrahedra that share  a cornercorner with one Ti(2)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid, corners with two equivalent Na(3)O5 trigonal bipyramids, and  an edgeedge with one Na(4)O5 trigonal bipyramid. In the second Ti site, Ti(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form TiO4 tetrahedra that share  a cornercorner with one Ti(1)O4 tetrahedra,  a cornercorner with one Na(3)O5 trigonal bipyramid, corners with two equivalent Na(4)O5 trigonal bipyramids, and  an edgeedge with one Na(3)O5 trigonal bipyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(6), and one Ti(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), and one Ti(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(5), one Na(6), and one Ti(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(4), one Na(5), one Na(6), and one Ti(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Na(3), and one Ti(2) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), and one Ti(2) atom. is represented by the CIF file [CIF]
data_Na6Ti2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.588
_cell_length_b   6.008
_cell_length_c   10.785
_cell_angle_alpha   57.131
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   467.397
_cell_formula_units_Z   2
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
  Na  Na0  1  0.575  0.772  0.408  1.0
  Na  Na1  1  0.440  0.099  0.086  1.0
  Na  Na2  1  0.725  0.484  0.821  1.0
  Na  Na3  1  0.217  0.913  0.389  1.0
  Na  Na4  1  0.073  0.606  0.816  1.0
  Na  Na5  1  0.947  0.278  0.129  1.0
  Na  Na6  1  0.425  0.772  0.908  1.0
  Na  Na7  1  0.560  0.099  0.586  1.0
  Na  Na8  1  0.783  0.913  0.889  1.0
  Na  Na9  1  0.275  0.484  0.321  1.0
  Na  Na10  1  0.053  0.278  0.629  1.0
  Na  Na11  1  0.927  0.606  0.316  1.0
  Ti  Ti12  1  0.102  0.974  0.002  1.0
  Ti  Ti13  1  0.407  0.401  0.719  1.0
  Ti  Ti14  1  0.898  0.974  0.502  1.0
  Ti  Ti15  1  0.593  0.401  0.219  1.0
  O  O16  1  0.340  0.485  0.538  1.0
  O  O17  1  0.278  0.157  0.881  1.0
  O  O18  1  0.939  0.202  0.921  1.0
  O  O19  1  0.130  0.899  0.188  1.0
  O  O20  1  0.931  0.678  0.502  1.0
  O  O21  1  0.438  0.695  0.723  1.0
  O  O22  1  0.416  0.215  0.260  1.0
  O  O23  1  0.660  0.485  0.038  1.0
  O  O24  1  0.722  0.157  0.381  1.0
  O  O25  1  0.870  0.899  0.688  1.0
  O  O26  1  0.061  0.202  0.421  1.0
  O  O27  1  0.069  0.678  0.002  1.0
  O  O28  1  0.584  0.215  0.760  1.0
  O  O29  1  0.562  0.695  0.223  1.0
[/CIF]
.
The material structure described by Na6Ti2O7 crystallizes in the monoclinic Pc space group. There are six inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), one O(6), and one O(7) atom. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and one O(7) atom. In the third Na site, Na(3) is bonded to one O(1), one O(3), one O(4), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Ti(2)O4 tetrahedra, corners with two equivalent Ti(1)O4 tetrahedra,  an edgeedge with one Ti(2)O4 tetrahedra, and edges with two equivalent Na(4)O5 trigonal bipyramids. In the fourth Na site, Na(4) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Ti(1)O4 tetrahedra, corners with two equivalent Ti(2)O4 tetrahedra,  an edgeedge with one Ti(1)O4 tetrahedra, and edges with two equivalent Na(3)O5 trigonal bipyramids. In the fifth Na site, Na(5) is bonded in a 3-coordinate geometry to one O(3), one O(4), and one O(5) atom. In the sixth Na site, Na(6) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(5) atom. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form TiO4 tetrahedra that share  a cornercorner with one Ti(2)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid, corners with two equivalent Na(3)O5 trigonal bipyramids, and  an edgeedge with one Na(4)O5 trigonal bipyramid. In the second Ti site, Ti(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form TiO4 tetrahedra that share  a cornercorner with one Ti(1)O4 tetrahedra,  a cornercorner with one Na(3)O5 trigonal bipyramid, corners with two equivalent Na(4)O5 trigonal bipyramids, and  an edgeedge with one Na(3)O5 trigonal bipyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(6), and one Ti(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), and one Ti(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(5), one Na(6), and one Ti(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(4), one Na(5), one Na(6), and one Ti(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Na(3), and one Ti(2) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), and one Ti(2) atom. is represented by the CIF file [CIF]
data_Na6Ti2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.588
_cell_length_b   6.008
_cell_length_c   10.785
_cell_angle_alpha   57.131
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   467.397
_cell_formula_units_Z   2
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
  Na  Na0  1  0.575  0.772  0.408  1.0
  Na  Na1  1  0.440  0.099  0.086  1.0
  Na  Na2  1  0.725  0.484  0.821  1.0
  Na  Na3  1  0.217  0.913  0.389  1.0
  Na  Na4  1  0.073  0.606  0.816  1.0
  Na  Na5  1  0.947  0.278  0.129  1.0
  Na  Na6  1  0.425  0.772  0.908  1.0
  Na  Na7  1  0.560  0.099  0.586  1.0
  Na  Na8  1  0.783  0.913  0.889  1.0
  Na  Na9  1  0.275  0.484  0.321  1.0
  Na  Na10  1  0.053  0.278  0.629  1.0
  Na  Na11  1  0.927  0.606  0.316  1.0
  Ti  Ti12  1  0.102  0.974  0.002  1.0
  Ti  Ti13  1  0.407  0.401  0.719  1.0
  Ti  Ti14  1  0.898  0.974  0.502  1.0
  Ti  Ti15  1  0.593  0.401  0.219  1.0
  O  O16  1  0.340  0.485  0.538  1.0
  O  O17  1  0.278  0.157  0.881  1.0
  O  O18  1  0.939  0.202  0.921  1.0
  O  O19  1  0.130  0.899  0.188  1.0
  O  O20  1  0.931  0.678  0.502  1.0
  O  O21  1  0.438  0.695  0.723  1.0
  O  O22  1  0.416  0.215  0.260  1.0
  O  O23  1  0.660  0.485  0.038  1.0
  O  O24  1  0.722  0.157  0.381  1.0
  O  O25  1  0.870  0.899  0.688  1.0
  O  O26  1  0.061  0.202  0.421  1.0
  O  O27  1  0.069  0.678  0.002  1.0
  O  O28  1  0.584  0.215  0.760  1.0
  O  O29  1  0.562  0.695  0.223  1.0
[/CIF]
.