The structure described by Na8Mg(FeO4)2 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) 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. In the second Na site, Na(2) is bonded to one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Fe(1)O4 tetrahedra, corners with three equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Fe(1)O4 tetrahedra, and  an edgeedge with one Fe(2)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(5), and one O(6) atom. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(6) atom. In the fifth Na site, Na(5) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(7), and one O(8) atom. In the sixth Na site, Na(6) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and one O(8) atom. In the seventh Na site, Na(7) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and one O(6) atom. In the eighth Na site, Na(8) is bonded in a trigonal non-coplanar geometry to one O(1), one O(4), and one O(5) atom. Mg(1) is bonded to one O(3), one O(6), one O(7), and one O(8) atom to form MgO4 tetrahedra that share corners with three equivalent Na(2)O5 square pyramids,  a cornercorner with one Fe(1)O4 tetrahedra, and corners with three equivalent Fe(2)O4 tetrahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form FeO4 tetrahedra that share  a cornercorner with one Na(2)O5 square pyramid,  a cornercorner with one Mg(1)O4 tetrahedra, and  an edgeedge with one Na(2)O5 square pyramid. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Mg(1)O4 tetrahedra and  an edgeedge with one Na(2)O5 square pyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(7), one Na(8), and one Fe(2) atom. In the second O site, O(2) is bonded to one Na(3), one Na(4), one Na(6), one Na(7), and one Fe(1) atom to form distorted corner-sharing ONa4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 48-67°. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(7), one Mg(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(5), one Na(6), one Na(8), and one Fe(1) atom to form corner-sharing ONa5Fe octahedra. In the fifth O site, O(5) is bonded in a 7-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(6), one Na(7), one Na(8), and one Fe(1) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(4), one Na(7), one Mg(1), and one Fe(2) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(5), one Mg(1), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Mg(1), and one Fe(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na8Mg(FeO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.781
_cell_length_b   5.752
_cell_length_c   9.002
_cell_angle_alpha   75.693
_cell_angle_beta   82.749
_cell_angle_gamma   70.477
_symmetry_Int_Tables_number   1
_cell_volume   273.050
_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  0.242  0.637  0.407  1.0
  Na  Na1  1  0.747  0.486  0.592  1.0
  Na  Na2  1  0.746  0.193  0.008  1.0
  Na  Na3  1  0.278  0.776  0.027  1.0
  Na  Na4  1  0.816  0.020  0.464  1.0
  Na  Na5  1  0.233  0.925  0.702  1.0
  Na  Na6  1  0.187  0.358  0.073  1.0
  Na  Na7  1  0.748  0.745  0.833  1.0
  Mg  Mg8  1  0.367  0.170  0.377  1.0
  Fe  Fe9  1  0.276  0.395  0.738  1.0
  Fe  Fe10  1  0.732  0.580  0.247  1.0
  O  O11  1  0.862  0.740  0.065  1.0
  O  O12  1  0.141  0.174  0.888  1.0
  O  O13  1  0.009  0.315  0.353  1.0
  O  O14  1  0.028  0.687  0.635  1.0
  O  O15  1  0.474  0.524  0.830  1.0
  O  O16  1  0.500  0.416  0.217  1.0
  O  O17  1  0.554  0.817  0.373  1.0
  O  O18  1  0.447  0.220  0.577  1.0
[/CIF]
.
The structure described by Na8Mg(FeO4)2 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) 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. In the second Na site, Na(2) is bonded to one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Fe(1)O4 tetrahedra, corners with three equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Fe(1)O4 tetrahedra, and  an edgeedge with one Fe(2)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(5), and one O(6) atom. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(6) atom. In the fifth Na site, Na(5) is bonded in a 4-coordinate geometry to one O(3), one O(4), one O(7), and one O(8) atom. In the sixth Na site, Na(6) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and one O(8) atom. In the seventh Na site, Na(7) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(5), and one O(6) atom. In the eighth Na site, Na(8) is bonded in a trigonal non-coplanar geometry to one O(1), one O(4), and one O(5) atom. Mg(1) is bonded to one O(3), one O(6), one O(7), and one O(8) atom to form MgO4 tetrahedra that share corners with three equivalent Na(2)O5 square pyramids,  a cornercorner with one Fe(1)O4 tetrahedra, and corners with three equivalent Fe(2)O4 tetrahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form FeO4 tetrahedra that share  a cornercorner with one Na(2)O5 square pyramid,  a cornercorner with one Mg(1)O4 tetrahedra, and  an edgeedge with one Na(2)O5 square pyramid. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form FeO4 tetrahedra that share corners with three equivalent Mg(1)O4 tetrahedra and  an edgeedge with one Na(2)O5 square pyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(7), one Na(8), and one Fe(2) atom. In the second O site, O(2) is bonded to one Na(3), one Na(4), one Na(6), one Na(7), and one Fe(1) atom to form distorted corner-sharing ONa4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 48-67°. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(7), one Mg(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(5), one Na(6), one Na(8), and one Fe(1) atom to form corner-sharing ONa5Fe octahedra. In the fifth O site, O(5) is bonded in a 7-coordinate geometry to one Na(2), one Na(3), one Na(4), one Na(6), one Na(7), one Na(8), and one Fe(1) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(4), one Na(7), one Mg(1), and one Fe(2) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(5), one Mg(1), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Mg(1), and one Fe(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na8Mg(FeO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.781
_cell_length_b   5.752
_cell_length_c   9.002
_cell_angle_alpha   75.693
_cell_angle_beta   82.749
_cell_angle_gamma   70.477
_symmetry_Int_Tables_number   1
_cell_volume   273.050
_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  0.242  0.637  0.407  1.0
  Na  Na1  1  0.747  0.486  0.592  1.0
  Na  Na2  1  0.746  0.193  0.008  1.0
  Na  Na3  1  0.278  0.776  0.027  1.0
  Na  Na4  1  0.816  0.020  0.464  1.0
  Na  Na5  1  0.233  0.925  0.702  1.0
  Na  Na6  1  0.187  0.358  0.073  1.0
  Na  Na7  1  0.748  0.745  0.833  1.0
  Mg  Mg8  1  0.367  0.170  0.377  1.0
  Fe  Fe9  1  0.276  0.395  0.738  1.0
  Fe  Fe10  1  0.732  0.580  0.247  1.0
  O  O11  1  0.862  0.740  0.065  1.0
  O  O12  1  0.141  0.174  0.888  1.0
  O  O13  1  0.009  0.315  0.353  1.0
  O  O14  1  0.028  0.687  0.635  1.0
  O  O15  1  0.474  0.524  0.830  1.0
  O  O16  1  0.500  0.416  0.217  1.0
  O  O17  1  0.554  0.817  0.373  1.0
  O  O18  1  0.447  0.220  0.577  1.0
[/CIF]
.