The material described by Na4Mg(NiO3)2 crystallizes in the monoclinic Cm space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO5 square pyramids that share  a cornercorner with one Na(1)O5 square pyramid, corners with four equivalent Ni(1)O5 trigonal bipyramids, corners with three equivalent Mg(1)O4 trigonal pyramids, edges with two equivalent Na(1)O5 square pyramids, and edges with two equivalent Ni(1)O5 trigonal bipyramids. In the second Na site, Na(2) is bonded in a distorted see-saw-like geometry to one O(1), one O(4), and two equivalent O(3) atoms. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. Mg(1) is bonded to one O(1), one O(4), and two equivalent O(2) atoms to form distorted MgO4 trigonal pyramids that share corners with six equivalent Na(1)O5 square pyramids, corners with two equivalent Ni(1)O5 trigonal bipyramids, and edges with two equivalent Ni(1)O5 trigonal bipyramids. Ni(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NiO5 trigonal bipyramids that share corners with four equivalent Na(1)O5 square pyramids,  a cornercorner with one Ni(1)O5 trigonal bipyramid,  a cornercorner with one Mg(1)O4 trigonal pyramid, edges with two equivalent Na(1)O5 square pyramids, edges with two equivalent Ni(1)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O4 trigonal pyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Mg(1), and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(3), two equivalent Na(1), one Mg(1), and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), and two equivalent Ni(1) atoms. In the fourth O site, O(4) is bonded in a trigonal bipyramidal geometry to one Na(2), one Na(3), two equivalent Na(1), and one Mg(1) atom. is represented by the CIF file [CIF]
data_Na4Mg(NiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.731
_cell_length_b   5.731
_cell_length_c   6.174
_cell_angle_alpha   84.660
_cell_angle_beta   95.340
_cell_angle_gamma   55.840
_symmetry_Int_Tables_number   1
_cell_volume   164.451
_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  0.153  0.206  0.461  1.0
  Na  Na1  1  0.794  0.847  0.461  1.0
  Na  Na2  1  0.596  0.404  0.626  1.0
  Na  Na3  1  0.909  0.091  0.998  1.0
  Mg  Mg4  1  0.388  0.612  0.189  1.0
  Ni  Ni5  1  0.680  0.714  0.965  1.0
  Ni  Ni6  1  0.286  0.320  0.965  1.0
  O  O7  1  0.358  0.642  0.868  1.0
  O  O8  1  0.057  0.580  0.166  1.0
  O  O9  1  0.420  0.943  0.166  1.0
  O  O10  1  0.918  0.475  0.778  1.0
  O  O11  1  0.525  0.082  0.778  1.0
  O  O12  1  0.742  0.258  0.317  1.0
[/CIF]
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The material described by Na4Mg(NiO3)2 crystallizes in the monoclinic Cm space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted NaO5 square pyramids that share  a cornercorner with one Na(1)O5 square pyramid, corners with four equivalent Ni(1)O5 trigonal bipyramids, corners with three equivalent Mg(1)O4 trigonal pyramids, edges with two equivalent Na(1)O5 square pyramids, and edges with two equivalent Ni(1)O5 trigonal bipyramids. In the second Na site, Na(2) is bonded in a distorted see-saw-like geometry to one O(1), one O(4), and two equivalent O(3) atoms. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. Mg(1) is bonded to one O(1), one O(4), and two equivalent O(2) atoms to form distorted MgO4 trigonal pyramids that share corners with six equivalent Na(1)O5 square pyramids, corners with two equivalent Ni(1)O5 trigonal bipyramids, and edges with two equivalent Ni(1)O5 trigonal bipyramids. Ni(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted NiO5 trigonal bipyramids that share corners with four equivalent Na(1)O5 square pyramids,  a cornercorner with one Ni(1)O5 trigonal bipyramid,  a cornercorner with one Mg(1)O4 trigonal pyramid, edges with two equivalent Na(1)O5 square pyramids, edges with two equivalent Ni(1)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O4 trigonal pyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Mg(1), and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(3), two equivalent Na(1), one Mg(1), and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), and two equivalent Ni(1) atoms. In the fourth O site, O(4) is bonded in a trigonal bipyramidal geometry to one Na(2), one Na(3), two equivalent Na(1), and one Mg(1) atom. is represented by the CIF file [CIF]
data_Na4Mg(NiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.731
_cell_length_b   5.731
_cell_length_c   6.174
_cell_angle_alpha   84.660
_cell_angle_beta   95.340
_cell_angle_gamma   55.840
_symmetry_Int_Tables_number   1
_cell_volume   164.451
_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  0.153  0.206  0.461  1.0
  Na  Na1  1  0.794  0.847  0.461  1.0
  Na  Na2  1  0.596  0.404  0.626  1.0
  Na  Na3  1  0.909  0.091  0.998  1.0
  Mg  Mg4  1  0.388  0.612  0.189  1.0
  Ni  Ni5  1  0.680  0.714  0.965  1.0
  Ni  Ni6  1  0.286  0.320  0.965  1.0
  O  O7  1  0.358  0.642  0.868  1.0
  O  O8  1  0.057  0.580  0.166  1.0
  O  O9  1  0.420  0.943  0.166  1.0
  O  O10  1  0.918  0.475  0.778  1.0
  O  O11  1  0.525  0.082  0.778  1.0
  O  O12  1  0.742  0.258  0.317  1.0
[/CIF]
.