The structure described by Na4CrO4 crystallizes in the triclinic P-1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), two equivalent O(2), and two equivalent O(4) atoms to form NaO5 square pyramids that share corners with three equivalent Na(2)O5 square pyramids,  a cornercorner with one Cr(1)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, edges with two equivalent Na(1)O5 square pyramids, edges with three equivalent Na(2)O5 square pyramids, and edges with two equivalent Cr(1)O4 tetrahedra. In the second Na site, Na(2) is bonded to one O(3), two equivalent O(2), and two equivalent O(4) atoms to form NaO5 square pyramids that share corners with three equivalent Na(1)O5 square pyramids, corners with two equivalent Na(4)O4 tetrahedra, corners with three equivalent Cr(1)O4 tetrahedra, edges with two equivalent Na(2)O5 square pyramids, edges with three equivalent Na(1)O5 square pyramids, and  an edgeedge with one Cr(1)O4 tetrahedra. In the third Na site, Na(3) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. In the fourth Na site, Na(4) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Na(1)O5 square pyramids, corners with two equivalent Na(2)O5 square pyramids, corners with four equivalent Cr(1)O4 tetrahedra, and edges with two equivalent Na(4)O4 tetrahedra. Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CrO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid, corners with three equivalent Na(2)O5 square pyramids, corners with four equivalent Na(4)O4 tetrahedra,  an edgeedge with one Na(2)O5 square pyramid, and edges with two equivalent Na(1)O5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(3), two equivalent Na(4), and one Cr(1) atom. In the second O site, O(2) is bonded to one Na(3), two equivalent Na(1), two equivalent Na(2), and one Cr(1) atom to form a mixture of corner and edge-sharing ONa5Cr octahedra. The corner-sharing octahedral tilt angles range from 11-26°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), two equivalent Na(4), and one Cr(1) atom to form a mixture of distorted corner and edge-sharing ONa5Cr octahedra. The corner-sharing octahedral tilt angles range from 12-15°. In the fourth O site, O(4) is bonded to one Na(3), two equivalent Na(1), two equivalent Na(2), and one Cr(1) atom to form a mixture of distorted corner and edge-sharing ONa5Cr octahedra. The corner-sharing octahedral tilt angles range from 11-26°. is represented by the CIF card [CIF]
data_Na4CrO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.659
_cell_length_b   5.661
_cell_length_c   8.569
_cell_angle_alpha   81.260
_cell_angle_beta   71.292
_cell_angle_gamma   68.303
_symmetry_Int_Tables_number   1
_cell_volume   241.410
_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  0.946  0.243  0.601  1.0
  Na  Na1  1  0.521  0.265  0.433  1.0
  Na  Na2  1  0.607  0.731  0.182  1.0
  Na  Na3  1  0.241  0.754  0.988  1.0
  Na  Na4  1  0.759  0.246  0.012  1.0
  Na  Na5  1  0.479  0.735  0.567  1.0
  Na  Na6  1  0.054  0.757  0.399  1.0
  Na  Na7  1  0.393  0.269  0.818  1.0
  Cr  Cr8  1  0.843  0.721  0.757  1.0
  Cr  Cr9  1  0.157  0.279  0.243  1.0
  O  O10  1  0.851  0.846  0.931  1.0
  O  O11  1  0.704  0.974  0.623  1.0
  O  O12  1  0.296  0.026  0.377  1.0
  O  O13  1  0.363  0.471  0.197  1.0
  O  O14  1  0.637  0.529  0.803  1.0
  O  O15  1  0.163  0.527  0.638  1.0
  O  O16  1  0.149  0.154  0.069  1.0
  O  O17  1  0.837  0.473  0.362  1.0
[/CIF]
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The structure described by Na4CrO4 crystallizes in the triclinic P-1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), two equivalent O(2), and two equivalent O(4) atoms to form NaO5 square pyramids that share corners with three equivalent Na(2)O5 square pyramids,  a cornercorner with one Cr(1)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, edges with two equivalent Na(1)O5 square pyramids, edges with three equivalent Na(2)O5 square pyramids, and edges with two equivalent Cr(1)O4 tetrahedra. In the second Na site, Na(2) is bonded to one O(3), two equivalent O(2), and two equivalent O(4) atoms to form NaO5 square pyramids that share corners with three equivalent Na(1)O5 square pyramids, corners with two equivalent Na(4)O4 tetrahedra, corners with three equivalent Cr(1)O4 tetrahedra, edges with two equivalent Na(2)O5 square pyramids, edges with three equivalent Na(1)O5 square pyramids, and  an edgeedge with one Cr(1)O4 tetrahedra. In the third Na site, Na(3) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. In the fourth Na site, Na(4) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Na(1)O5 square pyramids, corners with two equivalent Na(2)O5 square pyramids, corners with four equivalent Cr(1)O4 tetrahedra, and edges with two equivalent Na(4)O4 tetrahedra. Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CrO4 tetrahedra that share  a cornercorner with one Na(1)O5 square pyramid, corners with three equivalent Na(2)O5 square pyramids, corners with four equivalent Na(4)O4 tetrahedra,  an edgeedge with one Na(2)O5 square pyramid, and edges with two equivalent Na(1)O5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(3), two equivalent Na(4), and one Cr(1) atom. In the second O site, O(2) is bonded to one Na(3), two equivalent Na(1), two equivalent Na(2), and one Cr(1) atom to form a mixture of corner and edge-sharing ONa5Cr octahedra. The corner-sharing octahedral tilt angles range from 11-26°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), two equivalent Na(4), and one Cr(1) atom to form a mixture of distorted corner and edge-sharing ONa5Cr octahedra. The corner-sharing octahedral tilt angles range from 12-15°. In the fourth O site, O(4) is bonded to one Na(3), two equivalent Na(1), two equivalent Na(2), and one Cr(1) atom to form a mixture of distorted corner and edge-sharing ONa5Cr octahedra. The corner-sharing octahedral tilt angles range from 11-26°. is represented by the CIF card [CIF]
data_Na4CrO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.659
_cell_length_b   5.661
_cell_length_c   8.569
_cell_angle_alpha   81.260
_cell_angle_beta   71.292
_cell_angle_gamma   68.303
_symmetry_Int_Tables_number   1
_cell_volume   241.410
_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  0.946  0.243  0.601  1.0
  Na  Na1  1  0.521  0.265  0.433  1.0
  Na  Na2  1  0.607  0.731  0.182  1.0
  Na  Na3  1  0.241  0.754  0.988  1.0
  Na  Na4  1  0.759  0.246  0.012  1.0
  Na  Na5  1  0.479  0.735  0.567  1.0
  Na  Na6  1  0.054  0.757  0.399  1.0
  Na  Na7  1  0.393  0.269  0.818  1.0
  Cr  Cr8  1  0.843  0.721  0.757  1.0
  Cr  Cr9  1  0.157  0.279  0.243  1.0
  O  O10  1  0.851  0.846  0.931  1.0
  O  O11  1  0.704  0.974  0.623  1.0
  O  O12  1  0.296  0.026  0.377  1.0
  O  O13  1  0.363  0.471  0.197  1.0
  O  O14  1  0.637  0.529  0.803  1.0
  O  O15  1  0.163  0.527  0.638  1.0
  O  O16  1  0.149  0.154  0.069  1.0
  O  O17  1  0.837  0.473  0.362  1.0
[/CIF]
.