The material structure described by Na7Fe3O8 crystallizes in the triclinic P-1 space group. There are seven inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(5), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid,  a cornercorner with one Na(6)O4 trigonal pyramid,  an edgeedge with one Fe(2)O4 tetrahedra,  an edgeedge with one Na(4)O5 trigonal bipyramid,  an edgeedge with one Na(6)O4 trigonal pyramid, and edges with two equivalent Na(3)O4 trigonal pyramids. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(8) atom. In the third Na site, Na(3) is bonded to one O(2), one O(6), and two equivalent O(5) atoms to form NaO4 trigonal pyramids that share  a cornercorner with one Fe(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, corners with two equivalent Na(4)O5 trigonal bipyramids,  an edgeedge with one Na(4)O5 trigonal bipyramid, edges with two equivalent Na(1)O5 trigonal bipyramids, and  an edgeedge with one Na(3)O4 trigonal pyramid. In the fourth Na site, Na(4) is bonded to one O(5), two equivalent O(2), and two equivalent O(8) atoms to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid, corners with two equivalent Na(3)O4 trigonal pyramids, edges with two equivalent Fe(2)O4 tetrahedra,  an edgeedge with one Na(1)O5 trigonal bipyramid, edges with two equivalent Na(4)O5 trigonal bipyramids, and  an edgeedge with one Na(3)O4 trigonal pyramid. In the fifth Na site, Na(5) is bonded in a 6-coordinate geometry to one O(6), one O(7), two equivalent O(3), and two equivalent O(4) atoms. In the sixth Na site, Na(6) is bonded to one O(1), one O(3), and two equivalent O(7) atoms to form NaO4 trigonal pyramids that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with three equivalent Fe(3)O4 tetrahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid,  an edgeedge with one Na(1)O5 trigonal bipyramid, and  an edgeedge with one Na(6)O4 trigonal pyramid. In the seventh Na site, Na(7) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(6), one O(7), and one O(8) atom. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids,  a cornercorner with one Na(3)O4 trigonal pyramid, and corners with two equivalent Na(6)O4 trigonal pyramids. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), one O(5), and one O(8) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid,  a cornercorner with one Na(4)O5 trigonal bipyramid,  a cornercorner with one Na(6)O4 trigonal pyramid, corners with three equivalent Na(3)O4 trigonal pyramids,  an edgeedge with one Na(1)O5 trigonal bipyramid, and edges with two equivalent Na(4)O5 trigonal bipyramids. In the third Fe site, Fe(3) is bonded to one O(3), one O(4), one O(7), and one O(8) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid, corners with two equivalent Na(4)O5 trigonal bipyramids, and corners with three equivalent Na(6)O4 trigonal pyramids. There are eight inequivalent O sites. In the first O site, O(8) is bonded to one Na(2), one Na(7), two equivalent Na(4), one Fe(2), and one Fe(3) atom to form distorted ONa4Fe2 octahedra that share  a cornercorner with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(8)Na4Fe2 octahedra,  an edgeedge with one O(6)Na5Fe octahedra, and edges with two equivalent O(5)Na5Fe octahedra. The corner-sharing octahedral tilt angles are 16°. In the second O site, O(1) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(6), one Fe(1), and one Fe(2) atom. In the third O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), two equivalent Na(4), and one Fe(2) atom. In the fourth O site, O(3) is bonded in a 6-coordinate geometry to one Na(6), one Na(7), two equivalent Na(5), one Fe(1), and one Fe(3) atom. In the fifth O site, O(4) is bonded to one Na(2), one Na(7), two equivalent Na(5), one Fe(1), and one Fe(3) atom to form distorted ONa4Fe2 octahedra that share  a cornercorner with one O(8)Na4Fe2 octahedra,  a cornercorner with one O(5)Na5Fe octahedra,  a cornercorner with one O(6)Na5Fe octahedra,  an edgeedge with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(8)Na4Fe2 octahedra, and edges with two equivalent O(6)Na5Fe octahedra. The corner-sharing octahedral tilt angles range from 14-16°. In the sixth O site, O(5) is bonded to one Na(1), one Na(2), one Na(4), two equivalent Na(3), and one Fe(2) atom to form distorted ONa5Fe octahedra that share  a cornercorner with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(5)Na5Fe octahedra, edges with two equivalent O(8)Na4Fe2 octahedra, and edges with two equivalent O(6)Na5Fe octahedra. The corner-sharing octahedral tilt angles are 15°. In the seventh O site, O(6) is bonded to one Na(1), one Na(2), one Na(3), one Na(5), one Na(7), and one Fe(1) atom to form ONa5Fe octahedra that share  a cornercorner with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(8)Na4Fe2 octahedra, edges with two equivalent O(4)Na4Fe2 octahedra, and edges with two equivalent O(5)Na5Fe octahedra. The corner-sharing octahedral tilt angles are 14°. In the eighth O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(5), one Na(7), two equivalent Na(6), and one Fe(3) atom. is represented by the CIF card [CIF]
data_Na7Fe3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.871
_cell_length_b   8.314
_cell_length_c   11.262
_cell_angle_alpha   68.455
_cell_angle_beta   78.573
_cell_angle_gamma   70.336
_symmetry_Int_Tables_number   1
_cell_volume   479.773
_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  0.496  0.441  0.282  1.0
  Na  Na1  1  0.504  0.559  0.718  1.0
  Na  Na2  1  0.877  0.218  0.664  1.0
  Na  Na3  1  0.123  0.782  0.336  1.0
  Na  Na4  1  0.376  0.360  0.567  1.0
  Na  Na5  1  0.624  0.640  0.433  1.0
  Na  Na6  1  0.724  0.067  0.475  1.0
  Na  Na7  1  0.276  0.933  0.525  1.0
  Na  Na8  1  0.305  0.866  0.045  1.0
  Na  Na9  1  0.695  0.134  0.955  1.0
  Na  Na10  1  0.269  0.453  0.049  1.0
  Na  Na11  1  0.731  0.547  0.951  1.0
  Na  Na12  1  0.539  0.937  0.780  1.0
  Na  Na13  1  0.461  0.063  0.220  1.0
  Fe  Fe14  1  0.814  0.739  0.148  1.0
  Fe  Fe15  1  0.043  0.311  0.362  1.0
  Fe  Fe16  1  0.957  0.689  0.638  1.0
  Fe  Fe17  1  0.056  0.846  0.845  1.0
  Fe  Fe18  1  0.944  0.154  0.155  1.0
  Fe  Fe19  1  0.186  0.261  0.852  1.0
  O  O20  1  0.066  0.531  0.223  1.0
  O  O21  1  0.679  0.782  0.554  1.0
  O  O22  1  0.784  0.799  0.968  1.0
  O  O23  1  0.216  0.201  0.032  1.0
  O  O24  1  0.098  0.065  0.844  1.0
  O  O25  1  0.902  0.935  0.156  1.0
  O  O26  1  0.757  0.346  0.463  1.0
  O  O27  1  0.243  0.654  0.537  1.0
  O  O28  1  0.509  0.749  0.228  1.0
  O  O29  1  0.491  0.251  0.772  1.0
  O  O30  1  0.646  0.314  0.117  1.0
  O  O31  1  0.321  0.218  0.446  1.0
  O  O32  1  0.354  0.686  0.883  1.0
  O  O33  1  0.056  0.100  0.315  1.0
  O  O34  1  0.944  0.900  0.685  1.0
  O  O35  1  0.934  0.469  0.777  1.0
[/CIF]
.
The material structure described by Na7Fe3O8 crystallizes in the triclinic P-1 space group. There are seven inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(5), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra,  a cornercorner with one Na(4)O5 trigonal bipyramid,  a cornercorner with one Na(6)O4 trigonal pyramid,  an edgeedge with one Fe(2)O4 tetrahedra,  an edgeedge with one Na(4)O5 trigonal bipyramid,  an edgeedge with one Na(6)O4 trigonal pyramid, and edges with two equivalent Na(3)O4 trigonal pyramids. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(4), one O(5), one O(6), and one O(8) atom. In the third Na site, Na(3) is bonded to one O(2), one O(6), and two equivalent O(5) atoms to form NaO4 trigonal pyramids that share  a cornercorner with one Fe(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, corners with two equivalent Na(4)O5 trigonal bipyramids,  an edgeedge with one Na(4)O5 trigonal bipyramid, edges with two equivalent Na(1)O5 trigonal bipyramids, and  an edgeedge with one Na(3)O4 trigonal pyramid. In the fourth Na site, Na(4) is bonded to one O(5), two equivalent O(2), and two equivalent O(8) atoms to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid, corners with two equivalent Na(3)O4 trigonal pyramids, edges with two equivalent Fe(2)O4 tetrahedra,  an edgeedge with one Na(1)O5 trigonal bipyramid, edges with two equivalent Na(4)O5 trigonal bipyramids, and  an edgeedge with one Na(3)O4 trigonal pyramid. In the fifth Na site, Na(5) is bonded in a 6-coordinate geometry to one O(6), one O(7), two equivalent O(3), and two equivalent O(4) atoms. In the sixth Na site, Na(6) is bonded to one O(1), one O(3), and two equivalent O(7) atoms to form NaO4 trigonal pyramids that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with three equivalent Fe(3)O4 tetrahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid,  an edgeedge with one Na(1)O5 trigonal bipyramid, and  an edgeedge with one Na(6)O4 trigonal pyramid. In the seventh Na site, Na(7) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(6), one O(7), and one O(8) atom. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, corners with two equivalent Na(1)O5 trigonal bipyramids,  a cornercorner with one Na(3)O4 trigonal pyramid, and corners with two equivalent Na(6)O4 trigonal pyramids. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), one O(5), and one O(8) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid,  a cornercorner with one Na(4)O5 trigonal bipyramid,  a cornercorner with one Na(6)O4 trigonal pyramid, corners with three equivalent Na(3)O4 trigonal pyramids,  an edgeedge with one Na(1)O5 trigonal bipyramid, and edges with two equivalent Na(4)O5 trigonal bipyramids. In the third Fe site, Fe(3) is bonded to one O(3), one O(4), one O(7), and one O(8) atom to form FeO4 tetrahedra that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra,  a cornercorner with one Na(1)O5 trigonal bipyramid, corners with two equivalent Na(4)O5 trigonal bipyramids, and corners with three equivalent Na(6)O4 trigonal pyramids. There are eight inequivalent O sites. In the first O site, O(8) is bonded to one Na(2), one Na(7), two equivalent Na(4), one Fe(2), and one Fe(3) atom to form distorted ONa4Fe2 octahedra that share  a cornercorner with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(8)Na4Fe2 octahedra,  an edgeedge with one O(6)Na5Fe octahedra, and edges with two equivalent O(5)Na5Fe octahedra. The corner-sharing octahedral tilt angles are 16°. In the second O site, O(1) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(6), one Fe(1), and one Fe(2) atom. In the third O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), two equivalent Na(4), and one Fe(2) atom. In the fourth O site, O(3) is bonded in a 6-coordinate geometry to one Na(6), one Na(7), two equivalent Na(5), one Fe(1), and one Fe(3) atom. In the fifth O site, O(4) is bonded to one Na(2), one Na(7), two equivalent Na(5), one Fe(1), and one Fe(3) atom to form distorted ONa4Fe2 octahedra that share  a cornercorner with one O(8)Na4Fe2 octahedra,  a cornercorner with one O(5)Na5Fe octahedra,  a cornercorner with one O(6)Na5Fe octahedra,  an edgeedge with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(8)Na4Fe2 octahedra, and edges with two equivalent O(6)Na5Fe octahedra. The corner-sharing octahedral tilt angles range from 14-16°. In the sixth O site, O(5) is bonded to one Na(1), one Na(2), one Na(4), two equivalent Na(3), and one Fe(2) atom to form distorted ONa5Fe octahedra that share  a cornercorner with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(5)Na5Fe octahedra, edges with two equivalent O(8)Na4Fe2 octahedra, and edges with two equivalent O(6)Na5Fe octahedra. The corner-sharing octahedral tilt angles are 15°. In the seventh O site, O(6) is bonded to one Na(1), one Na(2), one Na(3), one Na(5), one Na(7), and one Fe(1) atom to form ONa5Fe octahedra that share  a cornercorner with one O(4)Na4Fe2 octahedra,  an edgeedge with one O(8)Na4Fe2 octahedra, edges with two equivalent O(4)Na4Fe2 octahedra, and edges with two equivalent O(5)Na5Fe octahedra. The corner-sharing octahedral tilt angles are 14°. In the eighth O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(5), one Na(7), two equivalent Na(6), and one Fe(3) atom. is represented by the CIF card [CIF]
data_Na7Fe3O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.871
_cell_length_b   8.314
_cell_length_c   11.262
_cell_angle_alpha   68.455
_cell_angle_beta   78.573
_cell_angle_gamma   70.336
_symmetry_Int_Tables_number   1
_cell_volume   479.773
_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  0.496  0.441  0.282  1.0
  Na  Na1  1  0.504  0.559  0.718  1.0
  Na  Na2  1  0.877  0.218  0.664  1.0
  Na  Na3  1  0.123  0.782  0.336  1.0
  Na  Na4  1  0.376  0.360  0.567  1.0
  Na  Na5  1  0.624  0.640  0.433  1.0
  Na  Na6  1  0.724  0.067  0.475  1.0
  Na  Na7  1  0.276  0.933  0.525  1.0
  Na  Na8  1  0.305  0.866  0.045  1.0
  Na  Na9  1  0.695  0.134  0.955  1.0
  Na  Na10  1  0.269  0.453  0.049  1.0
  Na  Na11  1  0.731  0.547  0.951  1.0
  Na  Na12  1  0.539  0.937  0.780  1.0
  Na  Na13  1  0.461  0.063  0.220  1.0
  Fe  Fe14  1  0.814  0.739  0.148  1.0
  Fe  Fe15  1  0.043  0.311  0.362  1.0
  Fe  Fe16  1  0.957  0.689  0.638  1.0
  Fe  Fe17  1  0.056  0.846  0.845  1.0
  Fe  Fe18  1  0.944  0.154  0.155  1.0
  Fe  Fe19  1  0.186  0.261  0.852  1.0
  O  O20  1  0.066  0.531  0.223  1.0
  O  O21  1  0.679  0.782  0.554  1.0
  O  O22  1  0.784  0.799  0.968  1.0
  O  O23  1  0.216  0.201  0.032  1.0
  O  O24  1  0.098  0.065  0.844  1.0
  O  O25  1  0.902  0.935  0.156  1.0
  O  O26  1  0.757  0.346  0.463  1.0
  O  O27  1  0.243  0.654  0.537  1.0
  O  O28  1  0.509  0.749  0.228  1.0
  O  O29  1  0.491  0.251  0.772  1.0
  O  O30  1  0.646  0.314  0.117  1.0
  O  O31  1  0.321  0.218  0.446  1.0
  O  O32  1  0.354  0.686  0.883  1.0
  O  O33  1  0.056  0.100  0.315  1.0
  O  O34  1  0.944  0.900  0.685  1.0
  O  O35  1  0.934  0.469  0.777  1.0
[/CIF]
.