The crystal structure described by Na4Ti7O16 crystallizes in the monoclinic P2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), one O(4), and two equivalent O(6) atoms to form NaO4 tetrahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, and corners with six equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-63°. In the second Na site, Na(2) is bonded to one O(1), one O(2), and two equivalent O(5) atoms to form NaO4 tetrahedra that share  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, and corners with six equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-67°. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted TiO6 octahedra that share corners with three equivalent Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra,  an edgeedge with one Ti(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. In the second Ti site, Ti(2) is bonded to two equivalent O(3) and four equivalent O(5) atoms to form TiO6 octahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, and edges with four equivalent Ti(1)O6 octahedra. In the third Ti site, Ti(3) is bonded to two equivalent O(2) and four equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with four equivalent Na(1)O4 tetrahedra, edges with two equivalent Ti(4)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. In the fourth Ti site, Ti(4) is bonded to two equivalent O(1) and four equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with four equivalent Na(1)O4 tetrahedra, edges with two equivalent Ti(3)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Ti(4), and two equivalent Ti(1) atoms to form a mixture of corner and edge-sharing ONaTi3 tetrahedra. In the second O site, O(2) is bonded to one Na(2), one Ti(3), and two equivalent Ti(1) atoms to form a mixture of corner and edge-sharing ONaTi3 tetrahedra. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Na(1), one Ti(2), and two equivalent Ti(1) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Na(1) and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Na(2), one Ti(1), and one Ti(2) atom. In the sixth O site, O(6) is bonded to one Na(1), one Ti(1), one Ti(3), and one Ti(4) atom to form a mixture of distorted corner and edge-sharing ONaTi3 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na4Ti7O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.085
_cell_length_b   6.174
_cell_length_c   9.026
_cell_angle_alpha   86.465
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   338.472
_cell_formula_units_Z   1
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  0.000  0.245  0.627  1.0
  Na  Na1  1  0.500  0.228  0.879  1.0
  Na  Na2  1  0.500  0.772  0.121  1.0
  Na  Na3  1  0.000  0.755  0.373  1.0
  Ti  Ti4  1  0.244  0.737  0.756  1.0
  Ti  Ti5  1  0.756  0.737  0.756  1.0
  Ti  Ti6  1  0.000  0.500  0.000  1.0
  Ti  Ti7  1  0.244  0.263  0.244  1.0
  Ti  Ti8  1  0.756  0.263  0.244  1.0
  Ti  Ti9  1  0.500  0.000  0.500  1.0
  Ti  Ti10  1  0.500  0.500  0.500  1.0
  O  O11  1  0.500  0.519  0.720  1.0
  O  O12  1  0.500  0.948  0.725  1.0
  O  O13  1  0.000  0.509  0.776  1.0
  O  O14  1  0.000  0.917  0.722  1.0
  O  O15  1  0.768  0.718  0.957  1.0
  O  O16  1  0.232  0.718  0.957  1.0
  O  O17  1  0.768  0.282  0.043  1.0
  O  O18  1  0.232  0.282  0.043  1.0
  O  O19  1  0.000  0.083  0.278  1.0
  O  O20  1  0.500  0.052  0.275  1.0
  O  O21  1  0.500  0.481  0.280  1.0
  O  O22  1  0.000  0.491  0.224  1.0
  O  O23  1  0.293  0.250  0.489  1.0
  O  O24  1  0.707  0.250  0.489  1.0
  O  O25  1  0.707  0.750  0.511  1.0
  O  O26  1  0.293  0.750  0.511  1.0
[/CIF]
.
The crystal structure described by Na4Ti7O16 crystallizes in the monoclinic P2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), one O(4), and two equivalent O(6) atoms to form NaO4 tetrahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, and corners with six equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-63°. In the second Na site, Na(2) is bonded to one O(1), one O(2), and two equivalent O(5) atoms to form NaO4 tetrahedra that share  a cornercorner with one Ti(3)O6 octahedra,  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Ti(2)O6 octahedra, and corners with six equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-67°. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted TiO6 octahedra that share corners with three equivalent Na(1)O4 tetrahedra, corners with three equivalent Na(2)O4 tetrahedra,  an edgeedge with one Ti(2)O6 octahedra,  an edgeedge with one Ti(3)O6 octahedra,  an edgeedge with one Ti(4)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. In the second Ti site, Ti(2) is bonded to two equivalent O(3) and four equivalent O(5) atoms to form TiO6 octahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, and edges with four equivalent Ti(1)O6 octahedra. In the third Ti site, Ti(3) is bonded to two equivalent O(2) and four equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with four equivalent Na(1)O4 tetrahedra, edges with two equivalent Ti(4)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. In the fourth Ti site, Ti(4) is bonded to two equivalent O(1) and four equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with four equivalent Na(1)O4 tetrahedra, edges with two equivalent Ti(3)O6 octahedra, and edges with four equivalent Ti(1)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Ti(4), and two equivalent Ti(1) atoms to form a mixture of corner and edge-sharing ONaTi3 tetrahedra. In the second O site, O(2) is bonded to one Na(2), one Ti(3), and two equivalent Ti(1) atoms to form a mixture of corner and edge-sharing ONaTi3 tetrahedra. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Na(1), one Ti(2), and two equivalent Ti(1) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Na(1) and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Na(2), one Ti(1), and one Ti(2) atom. In the sixth O site, O(6) is bonded to one Na(1), one Ti(1), one Ti(3), and one Ti(4) atom to form a mixture of distorted corner and edge-sharing ONaTi3 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na4Ti7O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.085
_cell_length_b   6.174
_cell_length_c   9.026
_cell_angle_alpha   86.465
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   338.472
_cell_formula_units_Z   1
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  0.000  0.245  0.627  1.0
  Na  Na1  1  0.500  0.228  0.879  1.0
  Na  Na2  1  0.500  0.772  0.121  1.0
  Na  Na3  1  0.000  0.755  0.373  1.0
  Ti  Ti4  1  0.244  0.737  0.756  1.0
  Ti  Ti5  1  0.756  0.737  0.756  1.0
  Ti  Ti6  1  0.000  0.500  0.000  1.0
  Ti  Ti7  1  0.244  0.263  0.244  1.0
  Ti  Ti8  1  0.756  0.263  0.244  1.0
  Ti  Ti9  1  0.500  0.000  0.500  1.0
  Ti  Ti10  1  0.500  0.500  0.500  1.0
  O  O11  1  0.500  0.519  0.720  1.0
  O  O12  1  0.500  0.948  0.725  1.0
  O  O13  1  0.000  0.509  0.776  1.0
  O  O14  1  0.000  0.917  0.722  1.0
  O  O15  1  0.768  0.718  0.957  1.0
  O  O16  1  0.232  0.718  0.957  1.0
  O  O17  1  0.768  0.282  0.043  1.0
  O  O18  1  0.232  0.282  0.043  1.0
  O  O19  1  0.000  0.083  0.278  1.0
  O  O20  1  0.500  0.052  0.275  1.0
  O  O21  1  0.500  0.481  0.280  1.0
  O  O22  1  0.000  0.491  0.224  1.0
  O  O23  1  0.293  0.250  0.489  1.0
  O  O24  1  0.707  0.250  0.489  1.0
  O  O25  1  0.707  0.750  0.511  1.0
  O  O26  1  0.293  0.750  0.511  1.0
[/CIF]
.