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 distorted rectangular see-saw-like geometry to one O(3), one O(4), one O(7), and one O(8) atom. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(7), and one O(8) atom. In the third Na site, Na(3) is bonded in a 4-coordinate 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 to one O(1), one O(2), one O(5), and one O(6) atom to form distorted NaO4 tetrahedra that share corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Na(8)O4 trigonal pyramids, and corners with three equivalent Mg(1)O4 trigonal pyramids. In the fifth Na site, Na(5) 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 sixth Na site, Na(6) is bonded in a rectangular see-saw-like geometry to one O(3), one O(4), one O(5), and one O(8) atom. In the seventh Na site, Na(7) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(6), and one O(7) atom. In the eighth Na site, Na(8) is bonded to one O(1), one O(4), one O(5), and one O(8) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, and  a cornercorner with one Mg(1)O4 trigonal pyramid. Mg(1) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form distorted MgO4 trigonal pyramids that share  a cornercorner with one Fe(1)O4 tetrahedra,  a cornercorner with one Fe(2)O4 tetrahedra, corners with three equivalent Na(4)O4 tetrahedra,  a cornercorner with one Na(8)O4 trigonal pyramid, and  an edgeedge with one 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 corners with two equivalent Na(4)O4 tetrahedra,  a cornercorner with one Mg(1)O4 trigonal pyramid, and corners with three equivalent Na(8)O4 trigonal pyramids. 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 two equivalent Na(4)O4 tetrahedra,  a cornercorner with one Na(8)O4 trigonal pyramid,  a cornercorner with one Mg(1)O4 trigonal pyramid, and  an edgeedge with one Mg(1)O4 trigonal 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(8), one Mg(1), and one Fe(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(7), one Mg(1), and one Fe(1) atom. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(5), one Na(6), one Na(7), and one Fe(2) atom to form a mixture of corner and edge-sharing ONa5Fe octahedra. The corner-sharing octahedral tilt angles range from 8-9°. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Na(8), and one Fe(1) atom. In the fifth O site, O(5) is bonded to one Na(2), one Na(3), one Na(4), one Na(6), one Na(8), and one Fe(1) atom to form a mixture of corner and edge-sharing ONa5Fe octahedra. The corner-sharing octahedral tilt angles range from 8-9°. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(7), one Mg(1), and one Fe(2) atom. In the seventh O site, O(7) 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 eighth O site, O(8) 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 edge-sharing ONa5Fe octahedra. is represented by the CIF file [CIF]
data_Na8Mg(FeO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.839
_cell_length_b   5.799
_cell_length_c   8.970
_cell_angle_alpha   72.396
_cell_angle_beta   88.440
_cell_angle_gamma   71.121
_symmetry_Int_Tables_number   1
_cell_volume   273.090
_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  0.201  0.567  0.420  1.0
  Na  Na1  1  0.719  0.493  0.584  1.0
  Na  Na2  1  0.846  0.395  0.945  1.0
  Na  Na3  1  0.255  0.733  0.995  1.0
  Na  Na4  1  0.713  0.036  0.448  1.0
  Na  Na5  1  0.217  0.981  0.605  1.0
  Na  Na6  1  0.197  0.206  0.227  1.0
  Na  Na7  1  0.697  0.877  0.790  1.0
  Mg  Mg8  1  0.568  0.038  0.096  1.0
  Fe  Fe9  1  0.295  0.414  0.757  1.0
  Fe  Fe10  1  0.713  0.533  0.242  1.0
  O  O11  1  0.836  0.741  0.063  1.0
  O  O12  1  0.263  0.170  0.957  1.0
  O  O13  1  0.954  0.317  0.403  1.0
  O  O14  1  1.000  0.674  0.648  1.0
  O  O15  1  0.487  0.602  0.792  1.0
  O  O16  1  0.584  0.317  0.172  1.0
  O  O17  1  0.485  0.804  0.302  1.0
  O  O18  1  0.460  0.237  0.616  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 distorted rectangular see-saw-like geometry to one O(3), one O(4), one O(7), and one O(8) atom. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(7), and one O(8) atom. In the third Na site, Na(3) is bonded in a 4-coordinate 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 to one O(1), one O(2), one O(5), and one O(6) atom to form distorted NaO4 tetrahedra that share corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Na(8)O4 trigonal pyramids, and corners with three equivalent Mg(1)O4 trigonal pyramids. In the fifth Na site, Na(5) 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 sixth Na site, Na(6) is bonded in a rectangular see-saw-like geometry to one O(3), one O(4), one O(5), and one O(8) atom. In the seventh Na site, Na(7) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(6), and one O(7) atom. In the eighth Na site, Na(8) is bonded to one O(1), one O(4), one O(5), and one O(8) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, and  a cornercorner with one Mg(1)O4 trigonal pyramid. Mg(1) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form distorted MgO4 trigonal pyramids that share  a cornercorner with one Fe(1)O4 tetrahedra,  a cornercorner with one Fe(2)O4 tetrahedra, corners with three equivalent Na(4)O4 tetrahedra,  a cornercorner with one Na(8)O4 trigonal pyramid, and  an edgeedge with one 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 corners with two equivalent Na(4)O4 tetrahedra,  a cornercorner with one Mg(1)O4 trigonal pyramid, and corners with three equivalent Na(8)O4 trigonal pyramids. 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 two equivalent Na(4)O4 tetrahedra,  a cornercorner with one Na(8)O4 trigonal pyramid,  a cornercorner with one Mg(1)O4 trigonal pyramid, and  an edgeedge with one Mg(1)O4 trigonal 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(8), one Mg(1), and one Fe(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(3), one Na(4), one Na(7), one Mg(1), and one Fe(1) atom. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(5), one Na(6), one Na(7), and one Fe(2) atom to form a mixture of corner and edge-sharing ONa5Fe octahedra. The corner-sharing octahedral tilt angles range from 8-9°. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(6), one Na(8), and one Fe(1) atom. In the fifth O site, O(5) is bonded to one Na(2), one Na(3), one Na(4), one Na(6), one Na(8), and one Fe(1) atom to form a mixture of corner and edge-sharing ONa5Fe octahedra. The corner-sharing octahedral tilt angles range from 8-9°. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(7), one Mg(1), and one Fe(2) atom. In the seventh O site, O(7) 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 eighth O site, O(8) 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 edge-sharing ONa5Fe octahedra. is represented by the CIF file [CIF]
data_Na8Mg(FeO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.839
_cell_length_b   5.799
_cell_length_c   8.970
_cell_angle_alpha   72.396
_cell_angle_beta   88.440
_cell_angle_gamma   71.121
_symmetry_Int_Tables_number   1
_cell_volume   273.090
_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  0.201  0.567  0.420  1.0
  Na  Na1  1  0.719  0.493  0.584  1.0
  Na  Na2  1  0.846  0.395  0.945  1.0
  Na  Na3  1  0.255  0.733  0.995  1.0
  Na  Na4  1  0.713  0.036  0.448  1.0
  Na  Na5  1  0.217  0.981  0.605  1.0
  Na  Na6  1  0.197  0.206  0.227  1.0
  Na  Na7  1  0.697  0.877  0.790  1.0
  Mg  Mg8  1  0.568  0.038  0.096  1.0
  Fe  Fe9  1  0.295  0.414  0.757  1.0
  Fe  Fe10  1  0.713  0.533  0.242  1.0
  O  O11  1  0.836  0.741  0.063  1.0
  O  O12  1  0.263  0.170  0.957  1.0
  O  O13  1  0.954  0.317  0.403  1.0
  O  O14  1  1.000  0.674  0.648  1.0
  O  O15  1  0.487  0.602  0.792  1.0
  O  O16  1  0.584  0.317  0.172  1.0
  O  O17  1  0.485  0.804  0.302  1.0
  O  O18  1  0.460  0.237  0.616  1.0
[/CIF]
.