The material structure described by Na8Mg(NiO4)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(1), one O(2), one O(3), one O(4), and one O(7) atom. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), one O(4), and one O(7) atom. In the third Na site, Na(3) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Na(6)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra,  a cornercorner with one Na(5)O4 trigonal pyramid,  an edgeedge with one Na(8)O4 tetrahedra, and  an edgeedge with one Na(5)O4 trigonal pyramid. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. In the fifth Na site, Na(5) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Na(3)O5 square pyramid,  a cornercorner with one Ni(2)O4 tetrahedra, corners with two equivalent Na(6)O4 tetrahedra, and  an edgeedge with one Na(3)O5 square pyramid. In the sixth Na site, Na(6) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(3)O5 square pyramid, corners with two equivalent Na(8)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, and corners with two equivalent Na(5)O4 trigonal pyramids. In the seventh Na site, Na(7) is bonded in a 3-coordinate geometry to one O(6), one O(7), and one O(8) atom. In the eighth Na site, Na(8) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form distorted NaO4 tetrahedra that share corners with two equivalent Na(6)O4 tetrahedra, corners with three equivalent Ni(2)O4 tetrahedra, and  an edgeedge with one Na(3)O5 square pyramid. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(5), one O(6), and one O(8) atom. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(4), one O(5), and one O(6) atom. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form NiO4 tetrahedra that share corners with two equivalent Na(3)O5 square pyramids, corners with two equivalent Na(6)O4 tetrahedra, corners with three equivalent Na(8)O4 tetrahedra, and  a cornercorner with one Na(5)O4 trigonal pyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(8), and one Ni(2) atom. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(8), and one Ni(2) atom to form distorted edge-sharing ONa5Ni octahedra. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(4), one Na(5), one Mg(1), and one Ni(1) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one Ni(1) atom to form distorted edge-sharing ONa5Ni octahedra. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), one Mg(1), and one Ni(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(6), one Na(7), one Na(8), one Mg(1), and one Ni(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(6), one Na(7), one Na(8), and one Ni(2) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(5), one Na(6), one Na(7), one Mg(1), and one Ni(2) atom. is represented by the CIF file [CIF]
data_Na8Mg(NiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.630
_cell_length_b   5.906
_cell_length_c   5.848
_cell_angle_alpha   69.045
_cell_angle_beta   106.858
_cell_angle_gamma   96.089
_symmetry_Int_Tables_number   1
_cell_volume   266.360
_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  0.199  0.990  0.671  1.0
  Na  Na1  1  0.126  0.503  0.115  1.0
  Na  Na2  1  0.313  0.535  0.674  1.0
  Na  Na3  1  0.325  0.015  0.200  1.0
  Na  Na4  1  0.572  0.031  0.670  1.0
  Na  Na5  1  0.718  0.512  0.888  1.0
  Na  Na6  1  0.859  0.137  0.451  1.0
  Na  Na7  1  0.948  0.566  0.576  1.0
  Mg  Mg8  1  0.657  0.833  0.193  1.0
  Ni  Ni9  1  0.481  0.515  0.310  1.0
  Ni  Ni10  1  0.984  0.983  0.018  1.0
  O  O11  1  0.108  0.243  0.855  1.0
  O  O12  1  0.110  0.800  0.338  1.0
  O  O13  1  0.427  0.759  0.979  1.0
  O  O14  1  0.350  0.284  0.441  1.0
  O  O15  1  0.549  0.758  0.474  1.0
  O  O16  1  0.698  0.467  0.315  1.0
  O  O17  1  0.934  0.793  0.810  1.0
  O  O18  1  0.787  0.093  0.039  1.0
[/CIF]
.
The material structure described by Na8Mg(NiO4)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(1), one O(2), one O(3), one O(4), and one O(7) atom. In the second Na site, Na(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(2), one O(4), and one O(7) atom. In the third Na site, Na(3) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form distorted NaO5 square pyramids that share  a cornercorner with one Na(6)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra,  a cornercorner with one Na(5)O4 trigonal pyramid,  an edgeedge with one Na(8)O4 tetrahedra, and  an edgeedge with one Na(5)O4 trigonal pyramid. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. In the fifth Na site, Na(5) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form distorted NaO4 trigonal pyramids that share  a cornercorner with one Na(3)O5 square pyramid,  a cornercorner with one Ni(2)O4 tetrahedra, corners with two equivalent Na(6)O4 tetrahedra, and  an edgeedge with one Na(3)O5 square pyramid. In the sixth Na site, Na(6) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form distorted NaO4 tetrahedra that share  a cornercorner with one Na(3)O5 square pyramid, corners with two equivalent Na(8)O4 tetrahedra, corners with two equivalent Ni(2)O4 tetrahedra, and corners with two equivalent Na(5)O4 trigonal pyramids. In the seventh Na site, Na(7) is bonded in a 3-coordinate geometry to one O(6), one O(7), and one O(8) atom. In the eighth Na site, Na(8) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form distorted NaO4 tetrahedra that share corners with two equivalent Na(6)O4 tetrahedra, corners with three equivalent Ni(2)O4 tetrahedra, and  an edgeedge with one Na(3)O5 square pyramid. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(5), one O(6), and one O(8) atom. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted rectangular see-saw-like geometry to one O(3), one O(4), one O(5), and one O(6) atom. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form NiO4 tetrahedra that share corners with two equivalent Na(3)O5 square pyramids, corners with two equivalent Na(6)O4 tetrahedra, corners with three equivalent Na(8)O4 tetrahedra, and  a cornercorner with one Na(5)O4 trigonal pyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(8), and one Ni(2) atom. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(8), and one Ni(2) atom to form distorted edge-sharing ONa5Ni octahedra. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(4), one Na(5), one Mg(1), and one Ni(1) atom. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one Ni(1) atom to form distorted edge-sharing ONa5Ni octahedra. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(3), one Na(4), one Na(5), one Na(6), one Mg(1), and one Ni(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(6), one Na(7), one Na(8), one Mg(1), and one Ni(1) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(6), one Na(7), one Na(8), and one Ni(2) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(5), one Na(6), one Na(7), one Mg(1), and one Ni(2) atom. is represented by the CIF file [CIF]
data_Na8Mg(NiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.630
_cell_length_b   5.906
_cell_length_c   5.848
_cell_angle_alpha   69.045
_cell_angle_beta   106.858
_cell_angle_gamma   96.089
_symmetry_Int_Tables_number   1
_cell_volume   266.360
_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  0.199  0.990  0.671  1.0
  Na  Na1  1  0.126  0.503  0.115  1.0
  Na  Na2  1  0.313  0.535  0.674  1.0
  Na  Na3  1  0.325  0.015  0.200  1.0
  Na  Na4  1  0.572  0.031  0.670  1.0
  Na  Na5  1  0.718  0.512  0.888  1.0
  Na  Na6  1  0.859  0.137  0.451  1.0
  Na  Na7  1  0.948  0.566  0.576  1.0
  Mg  Mg8  1  0.657  0.833  0.193  1.0
  Ni  Ni9  1  0.481  0.515  0.310  1.0
  Ni  Ni10  1  0.984  0.983  0.018  1.0
  O  O11  1  0.108  0.243  0.855  1.0
  O  O12  1  0.110  0.800  0.338  1.0
  O  O13  1  0.427  0.759  0.979  1.0
  O  O14  1  0.350  0.284  0.441  1.0
  O  O15  1  0.549  0.758  0.474  1.0
  O  O16  1  0.698  0.467  0.315  1.0
  O  O17  1  0.934  0.793  0.810  1.0
  O  O18  1  0.787  0.093  0.039  1.0
[/CIF]
.