The material structure described by Na2Te2O5 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Na(2)O6 octahedra, corners with six equivalent Na(1)O7 pentagonal bipyramids, and edges with two equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles are 25°. In the second Na site, Na(2) is bonded to one O(5), two equivalent O(3), and three equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with four equivalent Na(2)O6 octahedra,  a cornercorner with one Na(1)O7 pentagonal bipyramid, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Na(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 22-27°. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a 4-coordinate geometry to one O(2), one O(4), and two equivalent O(3) atoms. In the second Te site, Te(2) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(5), and two equivalent O(1) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1) and two equivalent Te(2) atoms to form a mixture of distorted corner and edge-sharing ONa2Te2 trigonal pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Te(1), and one Te(2) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to two equivalent Na(2) and two equivalent Te(1) atoms. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), three equivalent Na(2), and one Te(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one Te(2) atom. is represented by the CIF card [CIF]
data_Na2Te2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.961
_cell_length_b   11.961
_cell_length_c   9.690
_cell_angle_alpha   77.802
_cell_angle_beta   77.802
_cell_angle_gamma   23.509
_symmetry_Int_Tables_number   1
_cell_volume   539.956
_cell_formula_units_Z   4
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  0.836  0.823  0.207  1.0
  Na  Na1  1  0.177  0.164  0.293  1.0
  Na  Na2  1  0.164  0.177  0.793  1.0
  Na  Na3  1  0.823  0.836  0.707  1.0
  Na  Na4  1  0.932  0.966  0.411  1.0
  Na  Na5  1  0.034  0.068  0.089  1.0
  Na  Na6  1  0.068  0.034  0.589  1.0
  Na  Na7  1  0.966  0.932  0.911  1.0
  Te  Te8  1  0.444  0.437  0.177  1.0
  Te  Te9  1  0.563  0.556  0.323  1.0
  Te  Te10  1  0.556  0.563  0.823  1.0
  Te  Te11  1  0.437  0.444  0.677  1.0
  Te  Te12  1  0.397  0.223  0.454  1.0
  Te  Te13  1  0.777  0.603  0.046  1.0
  Te  Te14  1  0.603  0.777  0.546  1.0
  Te  Te15  1  0.223  0.397  0.954  1.0
  O  O16  1  0.501  0.005  0.365  1.0
  O  O17  1  0.995  0.499  0.135  1.0
  O  O18  1  0.499  0.995  0.635  1.0
  O  O19  1  0.005  0.501  0.865  1.0
  O  O20  1  0.357  0.351  0.248  1.0
  O  O21  1  0.649  0.643  0.252  1.0
  O  O22  1  0.643  0.649  0.752  1.0
  O  O23  1  0.351  0.357  0.748  1.0
  O  O24  1  0.424  0.485  0.361  1.0
  O  O25  1  0.515  0.576  0.139  1.0
  O  O26  1  0.576  0.515  0.639  1.0
  O  O27  1  0.485  0.424  0.861  1.0
  O  O28  1  0.829  0.066  0.155  1.0
  O  O29  1  0.934  0.171  0.345  1.0
  O  O30  1  0.171  0.934  0.845  1.0
  O  O31  1  0.066  0.829  0.655  1.0
  O  O32  1  0.951  0.754  0.962  1.0
  O  O33  1  0.246  0.049  0.538  1.0
  O  O34  1  0.049  0.246  0.038  1.0
  O  O35  1  0.754  0.951  0.462  1.0
[/CIF]
.
The material structure described by Na2Te2O5 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Na(2)O6 octahedra, corners with six equivalent Na(1)O7 pentagonal bipyramids, and edges with two equivalent Na(2)O6 octahedra. The corner-sharing octahedral tilt angles are 25°. In the second Na site, Na(2) is bonded to one O(5), two equivalent O(3), and three equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with four equivalent Na(2)O6 octahedra,  a cornercorner with one Na(1)O7 pentagonal bipyramid, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Na(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 22-27°. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a 4-coordinate geometry to one O(2), one O(4), and two equivalent O(3) atoms. In the second Te site, Te(2) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(5), and two equivalent O(1) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1) and two equivalent Te(2) atoms to form a mixture of distorted corner and edge-sharing ONa2Te2 trigonal pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Te(1), and one Te(2) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to two equivalent Na(2) and two equivalent Te(1) atoms. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), three equivalent Na(2), and one Te(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one Te(2) atom. is represented by the CIF card [CIF]
data_Na2Te2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.961
_cell_length_b   11.961
_cell_length_c   9.690
_cell_angle_alpha   77.802
_cell_angle_beta   77.802
_cell_angle_gamma   23.509
_symmetry_Int_Tables_number   1
_cell_volume   539.956
_cell_formula_units_Z   4
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  0.836  0.823  0.207  1.0
  Na  Na1  1  0.177  0.164  0.293  1.0
  Na  Na2  1  0.164  0.177  0.793  1.0
  Na  Na3  1  0.823  0.836  0.707  1.0
  Na  Na4  1  0.932  0.966  0.411  1.0
  Na  Na5  1  0.034  0.068  0.089  1.0
  Na  Na6  1  0.068  0.034  0.589  1.0
  Na  Na7  1  0.966  0.932  0.911  1.0
  Te  Te8  1  0.444  0.437  0.177  1.0
  Te  Te9  1  0.563  0.556  0.323  1.0
  Te  Te10  1  0.556  0.563  0.823  1.0
  Te  Te11  1  0.437  0.444  0.677  1.0
  Te  Te12  1  0.397  0.223  0.454  1.0
  Te  Te13  1  0.777  0.603  0.046  1.0
  Te  Te14  1  0.603  0.777  0.546  1.0
  Te  Te15  1  0.223  0.397  0.954  1.0
  O  O16  1  0.501  0.005  0.365  1.0
  O  O17  1  0.995  0.499  0.135  1.0
  O  O18  1  0.499  0.995  0.635  1.0
  O  O19  1  0.005  0.501  0.865  1.0
  O  O20  1  0.357  0.351  0.248  1.0
  O  O21  1  0.649  0.643  0.252  1.0
  O  O22  1  0.643  0.649  0.752  1.0
  O  O23  1  0.351  0.357  0.748  1.0
  O  O24  1  0.424  0.485  0.361  1.0
  O  O25  1  0.515  0.576  0.139  1.0
  O  O26  1  0.576  0.515  0.639  1.0
  O  O27  1  0.485  0.424  0.861  1.0
  O  O28  1  0.829  0.066  0.155  1.0
  O  O29  1  0.934  0.171  0.345  1.0
  O  O30  1  0.171  0.934  0.845  1.0
  O  O31  1  0.066  0.829  0.655  1.0
  O  O32  1  0.951  0.754  0.962  1.0
  O  O33  1  0.246  0.049  0.538  1.0
  O  O34  1  0.049  0.246  0.038  1.0
  O  O35  1  0.754  0.951  0.462  1.0
[/CIF]
.