The crystal structure described by Na2Te2O7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms to form distorted NaO8 hexagonal bipyramids that share corners with two equivalent Na(1)O8 hexagonal bipyramids, corners with two equivalent Te(1)O6 octahedra, edges with four equivalent Na(2)O8 hexagonal bipyramids, edges with two equivalent Te(1)O6 octahedra, and edges with four equivalent Te(2)O6 octahedra. The corner-sharing octahedral tilt angles are 48°. In the second Na site, Na(2) is bonded to four equivalent O(1) and four equivalent O(3) atoms to form distorted NaO8 hexagonal bipyramids that share edges with two equivalent Na(2)O8 hexagonal bipyramids, edges with four equivalent Na(1)O8 hexagonal bipyramids, edges with two equivalent Te(2)O6 octahedra, and edges with four equivalent Te(1)O6 octahedra. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form TeO6 octahedra that share corners with two equivalent Na(1)O8 hexagonal bipyramids, corners with four equivalent Te(2)O6 octahedra, edges with two equivalent Na(1)O8 hexagonal bipyramids, and edges with four equivalent Na(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 44°. In the second Te site, Te(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form TeO6 octahedra that share corners with two equivalent Te(2)O6 octahedra, corners with four equivalent Te(1)O6 octahedra, edges with two equivalent Na(2)O8 hexagonal bipyramids, and edges with four equivalent Na(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 41-44°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Te(1), and one Te(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Na(1) and two equivalent Te(2) atoms. In the third O site, O(3) is bonded to one Na(1), two equivalent Na(2), and one Te(1) atom to form a mixture of distorted edge and corner-sharing ONa3Te tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Te2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.241
_cell_length_b   7.241
_cell_length_c   7.241
_cell_angle_alpha   120.082
_cell_angle_beta   118.126
_cell_angle_gamma   91.568
_symmetry_Int_Tables_number   1
_cell_volume   271.905
_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  0.500  1.000  0.500  1.0
  Na  Na1  1  1.000  0.500  0.500  1.0
  Na  Na2  1  0.500  1.000  1.000  1.0
  Na  Na3  1  0.500  0.500  0.500  1.0
  Te  Te4  1  1.000  1.000  1.000  1.0
  Te  Te5  1  0.500  0.500  0.000  1.0
  Te  Te6  1  1.000  0.000  0.500  1.0
  Te  Te7  1  1.000  0.500  1.000  1.0
  O  O8  1  0.052  0.914  0.724  1.0
  O  O9  1  0.948  0.672  0.862  1.0
  O  O10  1  0.311  0.586  0.138  1.0
  O  O11  1  0.689  0.828  0.276  1.0
  O  O12  1  0.948  0.086  0.276  1.0
  O  O13  1  0.052  0.328  0.138  1.0
  O  O14  1  0.689  0.414  0.862  1.0
  O  O15  1  0.311  0.172  0.724  1.0
  O  O16  1  0.091  0.750  0.341  1.0
  O  O17  1  0.909  0.250  0.659  1.0
  O  O18  1  0.699  0.918  0.781  1.0
  O  O19  1  0.301  0.082  0.219  1.0
  O  O20  1  0.363  0.582  0.781  1.0
  O  O21  1  0.637  0.418  0.219  1.0
[/CIF]
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The crystal structure described by Na2Te2O7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms to form distorted NaO8 hexagonal bipyramids that share corners with two equivalent Na(1)O8 hexagonal bipyramids, corners with two equivalent Te(1)O6 octahedra, edges with four equivalent Na(2)O8 hexagonal bipyramids, edges with two equivalent Te(1)O6 octahedra, and edges with four equivalent Te(2)O6 octahedra. The corner-sharing octahedral tilt angles are 48°. In the second Na site, Na(2) is bonded to four equivalent O(1) and four equivalent O(3) atoms to form distorted NaO8 hexagonal bipyramids that share edges with two equivalent Na(2)O8 hexagonal bipyramids, edges with four equivalent Na(1)O8 hexagonal bipyramids, edges with two equivalent Te(2)O6 octahedra, and edges with four equivalent Te(1)O6 octahedra. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form TeO6 octahedra that share corners with two equivalent Na(1)O8 hexagonal bipyramids, corners with four equivalent Te(2)O6 octahedra, edges with two equivalent Na(1)O8 hexagonal bipyramids, and edges with four equivalent Na(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 44°. In the second Te site, Te(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form TeO6 octahedra that share corners with two equivalent Te(2)O6 octahedra, corners with four equivalent Te(1)O6 octahedra, edges with two equivalent Na(2)O8 hexagonal bipyramids, and edges with four equivalent Na(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 41-44°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Te(1), and one Te(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Na(1) and two equivalent Te(2) atoms. In the third O site, O(3) is bonded to one Na(1), two equivalent Na(2), and one Te(1) atom to form a mixture of distorted edge and corner-sharing ONa3Te tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Te2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.241
_cell_length_b   7.241
_cell_length_c   7.241
_cell_angle_alpha   120.082
_cell_angle_beta   118.126
_cell_angle_gamma   91.568
_symmetry_Int_Tables_number   1
_cell_volume   271.905
_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  0.500  1.000  0.500  1.0
  Na  Na1  1  1.000  0.500  0.500  1.0
  Na  Na2  1  0.500  1.000  1.000  1.0
  Na  Na3  1  0.500  0.500  0.500  1.0
  Te  Te4  1  1.000  1.000  1.000  1.0
  Te  Te5  1  0.500  0.500  0.000  1.0
  Te  Te6  1  1.000  0.000  0.500  1.0
  Te  Te7  1  1.000  0.500  1.000  1.0
  O  O8  1  0.052  0.914  0.724  1.0
  O  O9  1  0.948  0.672  0.862  1.0
  O  O10  1  0.311  0.586  0.138  1.0
  O  O11  1  0.689  0.828  0.276  1.0
  O  O12  1  0.948  0.086  0.276  1.0
  O  O13  1  0.052  0.328  0.138  1.0
  O  O14  1  0.689  0.414  0.862  1.0
  O  O15  1  0.311  0.172  0.724  1.0
  O  O16  1  0.091  0.750  0.341  1.0
  O  O17  1  0.909  0.250  0.659  1.0
  O  O18  1  0.699  0.918  0.781  1.0
  O  O19  1  0.301  0.082  0.219  1.0
  O  O20  1  0.363  0.582  0.781  1.0
  O  O21  1  0.637  0.418  0.219  1.0
[/CIF]
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