The crystal structure described by Na4MgMn4O8 crystallizes in the monoclinic Pm space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(6), two equivalent O(1), and two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(2), one O(8), two equivalent O(4), and two equivalent O(7) atoms. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(2), and two equivalent O(6) atoms. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(7), two equivalent O(3), and two equivalent O(8) atoms. Mg(1) is bonded to one O(1), one O(5), and two equivalent O(3) atoms to form MgO4 tetrahedra that share corners with two equivalent Mn(3)O5 square pyramids, corners with four equivalent Mn(1)O5 square pyramids, corners with two equivalent Mg(1)O4 tetrahedra, and  an edgeedge with one Mn(3)O5 square pyramid. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(6), two equivalent O(1), and two equivalent O(5) atoms to form MnO5 square pyramids that share corners with two equivalent Mn(2)O5 square pyramids, corners with four equivalent Mg(1)O4 tetrahedra, and edges with two equivalent Mn(1)O5 square pyramids. In the second Mn site, Mn(2) is bonded to one O(4), two equivalent O(2), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing MnO5 square pyramids. In the third Mn site, Mn(3) is bonded to one O(7), two equivalent O(3), and two equivalent O(8) atoms to form distorted MnO5 square pyramids that share corners with two equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mn(3)O5 square pyramids, edges with two equivalent Mn(4)O5 square pyramids, and  an edgeedge with one Mg(1)O4 tetrahedra. In the fourth Mn site, Mn(4) is bonded to one O(8), two equivalent O(4), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing MnO5 square pyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Mg(1), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded to one Na(1), one Na(2), two equivalent Na(3), and two equivalent Mn(2) atoms to form edge-sharing ONa4Mn2 octahedra. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Na(4), two equivalent Mg(1), and two equivalent Mn(3) atoms. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(3), two equivalent Na(2), one Mn(2), and two equivalent Mn(4) atoms. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Mg(1), and two equivalent Mn(1) atoms. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(1), two equivalent Na(3), one Mn(1), and two equivalent Mn(2) atoms. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(4), two equivalent Na(2), one Mn(3), and two equivalent Mn(4) atoms. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(2), two equivalent Na(4), one Mn(4), and two equivalent Mn(3) atoms. is represented by the CIF file [CIF]
data_Na4MgMn4O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.009
_cell_length_b   5.773
_cell_length_c   12.578
_cell_angle_alpha   92.644
_cell_angle_beta   90.001
_cell_angle_gamma   89.999
_symmetry_Int_Tables_number   1
_cell_volume   218.238
_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  0.250  0.370  0.016  1.0
  Na  Na1  1  0.250  0.116  0.645  1.0
  Na  Na2  1  0.750  0.495  0.821  1.0
  Na  Na3  1  0.750  0.076  0.421  1.0
  Mg  Mg4  1  0.750  0.348  0.217  1.0
  Mn  Mn5  1  0.250  0.849  0.098  1.0
  Mn  Mn6  1  0.750  0.969  0.865  1.0
  Mn  Mn7  1  0.750  0.568  0.419  1.0
  Mn  Mn8  1  0.250  0.634  0.621  1.0
  O  O9  1  0.750  0.617  0.123  1.0
  O  O10  1  0.250  0.194  0.842  1.0
  O  O11  1  0.250  0.352  0.323  1.0
  O  O12  1  0.750  0.807  0.700  1.0
  O  O13  1  0.750  0.095  0.103  1.0
  O  O14  1  0.250  0.772  0.916  1.0
  O  O15  1  0.750  0.404  0.578  1.0
  O  O16  1  0.250  0.800  0.471  1.0
[/CIF]
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The crystal structure described by Na4MgMn4O8 crystallizes in the monoclinic Pm space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(6), two equivalent O(1), and two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(2), one O(8), two equivalent O(4), and two equivalent O(7) atoms. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(2), and two equivalent O(6) atoms. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(7), two equivalent O(3), and two equivalent O(8) atoms. Mg(1) is bonded to one O(1), one O(5), and two equivalent O(3) atoms to form MgO4 tetrahedra that share corners with two equivalent Mn(3)O5 square pyramids, corners with four equivalent Mn(1)O5 square pyramids, corners with two equivalent Mg(1)O4 tetrahedra, and  an edgeedge with one Mn(3)O5 square pyramid. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(6), two equivalent O(1), and two equivalent O(5) atoms to form MnO5 square pyramids that share corners with two equivalent Mn(2)O5 square pyramids, corners with four equivalent Mg(1)O4 tetrahedra, and edges with two equivalent Mn(1)O5 square pyramids. In the second Mn site, Mn(2) is bonded to one O(4), two equivalent O(2), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing MnO5 square pyramids. In the third Mn site, Mn(3) is bonded to one O(7), two equivalent O(3), and two equivalent O(8) atoms to form distorted MnO5 square pyramids that share corners with two equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mn(3)O5 square pyramids, edges with two equivalent Mn(4)O5 square pyramids, and  an edgeedge with one Mg(1)O4 tetrahedra. In the fourth Mn site, Mn(4) is bonded to one O(8), two equivalent O(4), and two equivalent O(7) atoms to form a mixture of corner and edge-sharing MnO5 square pyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Mg(1), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded to one Na(1), one Na(2), two equivalent Na(3), and two equivalent Mn(2) atoms to form edge-sharing ONa4Mn2 octahedra. In the third O site, O(3) is bonded in a 6-coordinate geometry to two equivalent Na(4), two equivalent Mg(1), and two equivalent Mn(3) atoms. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Na(3), two equivalent Na(2), one Mn(2), and two equivalent Mn(4) atoms. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Mg(1), and two equivalent Mn(1) atoms. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Na(1), two equivalent Na(3), one Mn(1), and two equivalent Mn(2) atoms. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(4), two equivalent Na(2), one Mn(3), and two equivalent Mn(4) atoms. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Na(2), two equivalent Na(4), one Mn(4), and two equivalent Mn(3) atoms. is represented by the CIF file [CIF]
data_Na4MgMn4O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.009
_cell_length_b   5.773
_cell_length_c   12.578
_cell_angle_alpha   92.644
_cell_angle_beta   90.001
_cell_angle_gamma   89.999
_symmetry_Int_Tables_number   1
_cell_volume   218.238
_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  0.250  0.370  0.016  1.0
  Na  Na1  1  0.250  0.116  0.645  1.0
  Na  Na2  1  0.750  0.495  0.821  1.0
  Na  Na3  1  0.750  0.076  0.421  1.0
  Mg  Mg4  1  0.750  0.348  0.217  1.0
  Mn  Mn5  1  0.250  0.849  0.098  1.0
  Mn  Mn6  1  0.750  0.969  0.865  1.0
  Mn  Mn7  1  0.750  0.568  0.419  1.0
  Mn  Mn8  1  0.250  0.634  0.621  1.0
  O  O9  1  0.750  0.617  0.123  1.0
  O  O10  1  0.250  0.194  0.842  1.0
  O  O11  1  0.250  0.352  0.323  1.0
  O  O12  1  0.750  0.807  0.700  1.0
  O  O13  1  0.750  0.095  0.103  1.0
  O  O14  1  0.250  0.772  0.916  1.0
  O  O15  1  0.750  0.404  0.578  1.0
  O  O16  1  0.250  0.800  0.471  1.0
[/CIF]
.