The material structure described by Na2W2O7 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form distorted NaO6 pentagonal pyramids that share corners with two equivalent W(1)O6 octahedra, corners with three equivalent W(2)O4 tetrahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with four equivalent W(2)O4 tetrahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Na(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 46°. There are two inequivalent W sites. In the first W site, W(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted WO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with two equivalent W(1)O6 octahedra, corners with two equivalent Na(1)O6 pentagonal pyramids, corners with two equivalent W(2)O4 tetrahedra, and edges with two equivalent Na(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 38-46°. In the second W site, W(2) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form WO4 tetrahedra that share corners with two equivalent W(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, and corners with three equivalent Na(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 50-61°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Na(2) and one W(2) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Na(1), two equivalent Na(2), and one W(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one W(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one W(1), and one W(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1) and two equivalent W(1) atoms. is represented by the CIF card [CIF]
data_Na2W2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.091
_cell_length_b   7.091
_cell_length_c   15.044
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   117.246
_symmetry_Int_Tables_number   1
_cell_volume   672.569
_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  0.669  0.331  0.346  1.0
  Na  Na1  1  0.250  0.250  0.000  1.0
  Na  Na2  1  0.331  0.669  0.654  1.0
  Na  Na3  1  0.750  0.750  0.000  1.0
  Na  Na4  1  0.250  0.250  0.500  1.0
  Na  Na5  1  0.750  0.750  0.500  1.0
  Na  Na6  1  0.169  0.831  0.154  1.0
  Na  Na7  1  0.831  0.169  0.846  1.0
  W  W8  1  0.162  0.338  0.250  1.0
  W  W9  1  0.746  0.254  0.586  1.0
  W  W10  1  0.338  0.162  0.750  1.0
  W  W11  1  0.838  0.662  0.750  1.0
  W  W12  1  0.754  0.246  0.086  1.0
  W  W13  1  0.254  0.746  0.414  1.0
  W  W14  1  0.246  0.754  0.914  1.0
  W  W15  1  0.662  0.838  0.250  1.0
  O  O16  1  0.124  0.876  0.469  1.0
  O  O17  1  0.860  0.140  0.002  1.0
  O  O18  1  0.197  0.208  0.839  1.0
  O  O19  1  0.376  0.624  0.969  1.0
  O  O20  1  0.697  0.708  0.661  1.0
  O  O21  1  0.792  0.803  0.839  1.0
  O  O22  1  0.935  0.472  0.657  1.0
  O  O23  1  0.803  0.792  0.161  1.0
  O  O24  1  0.435  0.972  0.843  1.0
  O  O25  1  0.292  0.303  0.661  1.0
  O  O26  1  0.877  0.123  0.282  1.0
  O  O27  1  0.640  0.360  0.502  1.0
  O  O28  1  0.123  0.877  0.718  1.0
  O  O29  1  0.624  0.376  0.031  1.0
  O  O30  1  0.377  0.623  0.218  1.0
  O  O31  1  0.140  0.860  0.998  1.0
  O  O32  1  0.528  0.065  0.657  1.0
  O  O33  1  0.028  0.565  0.843  1.0
  O  O34  1  0.472  0.935  0.343  1.0
  O  O35  1  0.360  0.640  0.498  1.0
  O  O36  1  0.623  0.377  0.782  1.0
  O  O37  1  0.065  0.528  0.343  1.0
  O  O38  1  0.208  0.197  0.161  1.0
  O  O39  1  0.972  0.435  0.157  1.0
  O  O40  1  0.565  0.028  0.157  1.0
  O  O41  1  0.303  0.292  0.339  1.0
  O  O42  1  0.876  0.124  0.531  1.0
  O  O43  1  0.708  0.697  0.339  1.0
[/CIF]
.
The material structure described by Na2W2O7 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form distorted NaO6 pentagonal pyramids that share corners with two equivalent W(1)O6 octahedra, corners with three equivalent W(2)O4 tetrahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles are 49°. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with four equivalent W(2)O4 tetrahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Na(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 46°. There are two inequivalent W sites. In the first W site, W(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted WO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with two equivalent W(1)O6 octahedra, corners with two equivalent Na(1)O6 pentagonal pyramids, corners with two equivalent W(2)O4 tetrahedra, and edges with two equivalent Na(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 38-46°. In the second W site, W(2) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form WO4 tetrahedra that share corners with two equivalent W(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, and corners with three equivalent Na(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 50-61°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Na(2) and one W(2) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Na(1), two equivalent Na(2), and one W(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one W(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one W(1), and one W(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1) and two equivalent W(1) atoms. is represented by the CIF card [CIF]
data_Na2W2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.091
_cell_length_b   7.091
_cell_length_c   15.044
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   117.246
_symmetry_Int_Tables_number   1
_cell_volume   672.569
_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  0.669  0.331  0.346  1.0
  Na  Na1  1  0.250  0.250  0.000  1.0
  Na  Na2  1  0.331  0.669  0.654  1.0
  Na  Na3  1  0.750  0.750  0.000  1.0
  Na  Na4  1  0.250  0.250  0.500  1.0
  Na  Na5  1  0.750  0.750  0.500  1.0
  Na  Na6  1  0.169  0.831  0.154  1.0
  Na  Na7  1  0.831  0.169  0.846  1.0
  W  W8  1  0.162  0.338  0.250  1.0
  W  W9  1  0.746  0.254  0.586  1.0
  W  W10  1  0.338  0.162  0.750  1.0
  W  W11  1  0.838  0.662  0.750  1.0
  W  W12  1  0.754  0.246  0.086  1.0
  W  W13  1  0.254  0.746  0.414  1.0
  W  W14  1  0.246  0.754  0.914  1.0
  W  W15  1  0.662  0.838  0.250  1.0
  O  O16  1  0.124  0.876  0.469  1.0
  O  O17  1  0.860  0.140  0.002  1.0
  O  O18  1  0.197  0.208  0.839  1.0
  O  O19  1  0.376  0.624  0.969  1.0
  O  O20  1  0.697  0.708  0.661  1.0
  O  O21  1  0.792  0.803  0.839  1.0
  O  O22  1  0.935  0.472  0.657  1.0
  O  O23  1  0.803  0.792  0.161  1.0
  O  O24  1  0.435  0.972  0.843  1.0
  O  O25  1  0.292  0.303  0.661  1.0
  O  O26  1  0.877  0.123  0.282  1.0
  O  O27  1  0.640  0.360  0.502  1.0
  O  O28  1  0.123  0.877  0.718  1.0
  O  O29  1  0.624  0.376  0.031  1.0
  O  O30  1  0.377  0.623  0.218  1.0
  O  O31  1  0.140  0.860  0.998  1.0
  O  O32  1  0.528  0.065  0.657  1.0
  O  O33  1  0.028  0.565  0.843  1.0
  O  O34  1  0.472  0.935  0.343  1.0
  O  O35  1  0.360  0.640  0.498  1.0
  O  O36  1  0.623  0.377  0.782  1.0
  O  O37  1  0.065  0.528  0.343  1.0
  O  O38  1  0.208  0.197  0.161  1.0
  O  O39  1  0.972  0.435  0.157  1.0
  O  O40  1  0.565  0.028  0.157  1.0
  O  O41  1  0.303  0.292  0.339  1.0
  O  O42  1  0.876  0.124  0.531  1.0
  O  O43  1  0.708  0.697  0.339  1.0
[/CIF]
.