The crystal structure described by Na2W2O7 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 10-coordinate geometry to one O(4), two equivalent O(5), two equivalent O(6), two equivalent O(7), and three equivalent O(2) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(3), one O(5), one O(7), and two equivalent O(4) atoms to form distorted corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 10-27°. In the second W site, W(2) is bonded to one O(5), one O(7), two equivalent O(2), and two equivalent O(6) atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 10-27°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Na(1) and one W(1) atom to form a mixture of distorted corner and edge-sharing ONa3W trigonal pyramids. In the second O site, O(2) is bonded to three equivalent Na(2) and two equivalent W(2) atoms to form a mixture of distorted corner and edge-sharing ONa3W2 square pyramids. In the third O site, O(3) is bonded to three equivalent Na(1) and one W(1) atom to form a mixture of corner and edge-sharing ONa3W tetrahedra. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Na(2) and two equivalent W(1) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(2), one W(1), and one W(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2) and two equivalent W(2) atoms. In the seventh O site, O(7) is bonded in a distorted see-saw-like geometry to two equivalent Na(2), one W(1), and one W(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2W2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.879
_cell_length_b   5.524
_cell_length_c   13.806
_cell_angle_alpha   90.000
_cell_angle_beta   98.075
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   292.854
_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  0.784  0.571  0.567  1.0
  Na  Na1  1  0.216  0.071  0.433  1.0
  Na  Na2  1  0.054  0.615  0.107  1.0
  Na  Na3  1  0.946  0.115  0.893  1.0
  W  W4  1  0.342  0.095  0.684  1.0
  W  W5  1  0.658  0.595  0.316  1.0
  W  W6  1  0.447  0.607  0.894  1.0
  W  W7  1  0.553  0.107  0.106  1.0
  O  O8  1  0.308  0.819  0.615  1.0
  O  O9  1  0.692  0.319  0.385  1.0
  O  O10  1  0.953  0.609  0.906  1.0
  O  O11  1  0.047  0.109  0.094  1.0
  O  O12  1  0.291  0.304  0.583  1.0
  O  O13  1  0.709  0.804  0.417  1.0
  O  O14  1  0.854  0.110  0.708  1.0
  O  O15  1  0.146  0.610  0.292  1.0
  O  O16  1  0.605  0.895  0.211  1.0
  O  O17  1  0.395  0.395  0.789  1.0
  O  O18  1  0.492  0.320  0.984  1.0
  O  O19  1  0.410  0.895  0.820  1.0
  O  O20  1  0.590  0.395  0.180  1.0
  O  O21  1  0.508  0.820  0.016  1.0
[/CIF]
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The crystal structure described by Na2W2O7 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 10-coordinate geometry to one O(4), two equivalent O(5), two equivalent O(6), two equivalent O(7), and three equivalent O(2) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(3), one O(5), one O(7), and two equivalent O(4) atoms to form distorted corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 10-27°. In the second W site, W(2) is bonded to one O(5), one O(7), two equivalent O(2), and two equivalent O(6) atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 10-27°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Na(1) and one W(1) atom to form a mixture of distorted corner and edge-sharing ONa3W trigonal pyramids. In the second O site, O(2) is bonded to three equivalent Na(2) and two equivalent W(2) atoms to form a mixture of distorted corner and edge-sharing ONa3W2 square pyramids. In the third O site, O(3) is bonded to three equivalent Na(1) and one W(1) atom to form a mixture of corner and edge-sharing ONa3W tetrahedra. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Na(2) and two equivalent W(1) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(2), one W(1), and one W(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2) and two equivalent W(2) atoms. In the seventh O site, O(7) is bonded in a distorted see-saw-like geometry to two equivalent Na(2), one W(1), and one W(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2W2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.879
_cell_length_b   5.524
_cell_length_c   13.806
_cell_angle_alpha   90.000
_cell_angle_beta   98.075
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   292.854
_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  0.784  0.571  0.567  1.0
  Na  Na1  1  0.216  0.071  0.433  1.0
  Na  Na2  1  0.054  0.615  0.107  1.0
  Na  Na3  1  0.946  0.115  0.893  1.0
  W  W4  1  0.342  0.095  0.684  1.0
  W  W5  1  0.658  0.595  0.316  1.0
  W  W6  1  0.447  0.607  0.894  1.0
  W  W7  1  0.553  0.107  0.106  1.0
  O  O8  1  0.308  0.819  0.615  1.0
  O  O9  1  0.692  0.319  0.385  1.0
  O  O10  1  0.953  0.609  0.906  1.0
  O  O11  1  0.047  0.109  0.094  1.0
  O  O12  1  0.291  0.304  0.583  1.0
  O  O13  1  0.709  0.804  0.417  1.0
  O  O14  1  0.854  0.110  0.708  1.0
  O  O15  1  0.146  0.610  0.292  1.0
  O  O16  1  0.605  0.895  0.211  1.0
  O  O17  1  0.395  0.395  0.789  1.0
  O  O18  1  0.492  0.320  0.984  1.0
  O  O19  1  0.410  0.895  0.820  1.0
  O  O20  1  0.590  0.395  0.180  1.0
  O  O21  1  0.508  0.820  0.016  1.0
[/CIF]
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