The crystal structure described by Na4W4O15 crystallizes in the triclinic P-1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(7) atoms. In the second Na site, Na(2) is bonded to one O(4), one O(6), one O(8), and two equivalent O(5) atoms to form NaO5 square pyramids that share corners with three equivalent W(1)O6 octahedra and  an edgeedge with one Na(2)O5 square pyramid. The corner-sharing octahedral tilt angles range from 47-66°. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(5), one O(7), one O(8), and two equivalent O(1) atoms to form distorted WO6 octahedra that share corners with three equivalent Na(2)O5 square pyramids and  an edgeedge with one W(1)O6 octahedra. In the second W site, W(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(8) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one W(2) and two equivalent W(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one W(1), and one W(2) atom. In the third O site, O(3) is bonded in a linear geometry to two equivalent Na(1) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one W(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(2), and one W(1) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Na(1), one Na(2), and one W(2) atom. In the seventh O site, O(7) is bonded to two equivalent Na(1), one W(1), and one W(2) atom to form distorted edge-sharing ONa2W2 trigonal pyramids. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Na(2), one W(1), and one W(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na4W4O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.297
_cell_length_b   7.740
_cell_length_c   8.922
_cell_angle_alpha   112.864
_cell_angle_beta   96.307
_cell_angle_gamma   92.844
_symmetry_Int_Tables_number   1
_cell_volume   333.303
_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  0.731  0.226  0.125  1.0
  Na  Na1  1  0.269  0.774  0.875  1.0
  Na  Na2  1  0.326  0.515  0.311  1.0
  Na  Na3  1  0.674  0.485  0.689  1.0
  W  W4  1  0.350  0.035  0.344  1.0
  W  W5  1  0.650  0.965  0.656  1.0
  W  W6  1  0.185  0.233  0.815  1.0
  W  W7  1  0.815  0.767  0.185  1.0
  O  O8  1  0.336  0.085  0.576  1.0
  O  O9  1  0.664  0.915  0.424  1.0
  O  O10  1  0.012  0.061  0.275  1.0
  O  O11  1  0.988  0.939  0.725  1.0
  O  O12  1  0.000  0.000  0.000  1.0
  O  O13  1  0.132  0.310  0.026  1.0
  O  O14  1  0.868  0.690  0.974  1.0
  O  O15  1  0.488  0.266  0.375  1.0
  O  O16  1  0.512  0.734  0.625  1.0
  O  O17  1  0.676  0.554  0.190  1.0
  O  O18  1  0.324  0.446  0.810  1.0
  O  O19  1  0.494  0.098  0.850  1.0
  O  O20  1  0.506  0.902  0.150  1.0
  O  O21  1  0.144  0.767  0.294  1.0
  O  O22  1  0.856  0.233  0.706  1.0
[/CIF]
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The crystal structure described by Na4W4O15 crystallizes in the triclinic P-1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(7) atoms. In the second Na site, Na(2) is bonded to one O(4), one O(6), one O(8), and two equivalent O(5) atoms to form NaO5 square pyramids that share corners with three equivalent W(1)O6 octahedra and  an edgeedge with one Na(2)O5 square pyramid. The corner-sharing octahedral tilt angles range from 47-66°. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(5), one O(7), one O(8), and two equivalent O(1) atoms to form distorted WO6 octahedra that share corners with three equivalent Na(2)O5 square pyramids and  an edgeedge with one W(1)O6 octahedra. In the second W site, W(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(8) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one W(2) and two equivalent W(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one W(1), and one W(2) atom. In the third O site, O(3) is bonded in a linear geometry to two equivalent Na(1) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one W(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(2), and one W(1) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Na(1), one Na(2), and one W(2) atom. In the seventh O site, O(7) is bonded to two equivalent Na(1), one W(1), and one W(2) atom to form distorted edge-sharing ONa2W2 trigonal pyramids. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Na(2), one W(1), and one W(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na4W4O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.297
_cell_length_b   7.740
_cell_length_c   8.922
_cell_angle_alpha   112.864
_cell_angle_beta   96.307
_cell_angle_gamma   92.844
_symmetry_Int_Tables_number   1
_cell_volume   333.303
_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  0.731  0.226  0.125  1.0
  Na  Na1  1  0.269  0.774  0.875  1.0
  Na  Na2  1  0.326  0.515  0.311  1.0
  Na  Na3  1  0.674  0.485  0.689  1.0
  W  W4  1  0.350  0.035  0.344  1.0
  W  W5  1  0.650  0.965  0.656  1.0
  W  W6  1  0.185  0.233  0.815  1.0
  W  W7  1  0.815  0.767  0.185  1.0
  O  O8  1  0.336  0.085  0.576  1.0
  O  O9  1  0.664  0.915  0.424  1.0
  O  O10  1  0.012  0.061  0.275  1.0
  O  O11  1  0.988  0.939  0.725  1.0
  O  O12  1  0.000  0.000  0.000  1.0
  O  O13  1  0.132  0.310  0.026  1.0
  O  O14  1  0.868  0.690  0.974  1.0
  O  O15  1  0.488  0.266  0.375  1.0
  O  O16  1  0.512  0.734  0.625  1.0
  O  O17  1  0.676  0.554  0.190  1.0
  O  O18  1  0.324  0.446  0.810  1.0
  O  O19  1  0.494  0.098  0.850  1.0
  O  O20  1  0.506  0.902  0.150  1.0
  O  O21  1  0.144  0.767  0.294  1.0
  O  O22  1  0.856  0.233  0.706  1.0
[/CIF]
.