The crystal structure described by Na4Mg(Ni2O5)2 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(8) atom to form distorted NaO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-19°. In the second Na site, Na(2) is bonded to one O(10), one O(3), one O(4), one O(5), one O(6), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-21°. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(2), one O(5), one O(7), and one O(8) atom. In the fourth Na site, Na(4) is bonded to one O(2), one O(3), one O(4), one O(6), one O(8), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-19°. Mg(1) is bonded to one O(10), one O(2), one O(4), one O(5), one O(7), and one O(9) atom to form MgO6 octahedra that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one Na(4)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-21°. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with two equivalent Na(4)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. In the second Ni site, Ni(2) is bonded to one O(1), one O(10), one O(3), one O(4), one O(6), and one O(8) atom to form NiO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-18°. In the third Ni site, Ni(3) is bonded to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(4)O6 octahedra, corners with two equivalent Na(1)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-17°. In the fourth Ni site, Ni(4) is bonded to one O(10), one O(3), one O(4), one O(7), one O(8), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-19°. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Ni(1), one Ni(2), and one Ni(3) atom to form ONa2Ni3 square pyramids that share corners with two equivalent O(6)Na3Ni3 octahedra,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid, corners with two equivalent O(10)Na2MgNi2 square pyramids, corners with three equivalent O(7)Na2MgNi2 square pyramids,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra, edges with two equivalent O(2)Na3MgNi2 octahedra, edges with two equivalent O(8)Na3Ni3 octahedra,  an edgeedge with one O(5)Na2MgNi2 square pyramid, and  an edgeedge with one O(3)Na2Ni3 square pyramid. The corner-sharing octahedral tilt angles are 4°. In the second O site, O(2) is bonded to one Na(1), one Na(3), one Na(4), one Mg(1), one Ni(1), and one Ni(3) atom to form distorted ONa3MgNi2 octahedra that share  a cornercorner with one O(4)Na3MgNi2 octahedra, corners with two equivalent O(8)Na3Ni3 octahedra,  a cornercorner with one O(9)Na2MgNi2 square pyramid, corners with two equivalent O(5)Na2MgNi2 square pyramids,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra, edges with two equivalent O(6)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid,  an edgeedge with one O(3)Na2Ni3 square pyramid, edges with two equivalent O(7)Na2MgNi2 square pyramids, and edges with two equivalent O(1)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 2-5°. In the third O site, O(3) is bonded to one Na(2), one Na(4), one Ni(1), one Ni(2), and one Ni(4) atom to form ONa2Ni3 square pyramids that share corners with two equivalent O(8)Na3Ni3 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid, corners with two equivalent O(5)Na2MgNi2 square pyramids, corners with three equivalent O(9)Na2MgNi2 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra, edges with two equivalent O(4)Na3MgNi2 octahedra, edges with two equivalent O(6)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid, and  an edgeedge with one O(1)Na2Ni3 square pyramid. The corner-sharing octahedral tilt angles range from 5-11°. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(4), one Mg(1), one Ni(2), and one Ni(4) atom to form ONa3MgNi2 octahedra that share  a cornercorner with one O(2)Na3MgNi2 octahedra, corners with two equivalent O(6)Na3Ni3 octahedra,  a cornercorner with one O(7)Na2MgNi2 square pyramid, corners with two equivalent O(10)Na2MgNi2 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra, edges with two equivalent O(8)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(1)Na2Ni3 square pyramid, edges with two equivalent O(9)Na2MgNi2 square pyramids, and edges with two equivalent O(3)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 3-11°. In the fifth O site, O(5) is bonded to one Na(2), one Na(3), one Mg(1), one Ni(1), and one Ni(3) atom to form ONa2MgNi2 square pyramids that share  a cornercorner with one O(6)Na3Ni3 octahedra, corners with two equivalent O(2)Na3MgNi2 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid,  a cornercorner with one O(1)Na2Ni3 square pyramid, corners with two equivalent O(3)Na2Ni3 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid, and  an edgeedge with one O(1)Na2Ni3 square pyramid. The corner-sharing octahedral tilt angles range from 5-10°. In the sixth O site, O(6) is bonded to one Na(1), one Na(2), one Na(4), one Ni(1), one Ni(2), and one Ni(3) atom to form distorted ONa3Ni3 octahedra that share corners with two equivalent O(4)Na3MgNi2 octahedra,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid, corners with two equivalent O(1)Na2Ni3 square pyramids,  an edgeedge with one O(4)Na3MgNi2 octahedra, edges with two equivalent O(2)Na3MgNi2 octahedra, edges with two equivalent O(8)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid,  an edgeedge with one O(1)Na2Ni3 square pyramid, and edges with two equivalent O(3)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 3-11°. In the seventh O site, O(7) is bonded to one Na(1), one Na(3), one Mg(1), one Ni(3), and one Ni(4) atom to form ONa2MgNi2 square pyramids that share  a cornercorner with one O(4)Na3MgNi2 octahedra,  a cornercorner with one O(8)Na3Ni3 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid,  a cornercorner with one O(3)Na2Ni3 square pyramid, corners with three equivalent O(1)Na2Ni3 square pyramids,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra, edges with two equivalent O(2)Na3MgNi2 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid, and  an edgeedge with one O(9)Na2MgNi2 square pyramid. The corner-sharing octahedral tilt angles range from 5-11°. In the eighth O site, O(8) is bonded to one Na(1), one Na(3), one Na(4), one Ni(1), one Ni(2), and one Ni(4) atom to form distorted ONa3Ni3 octahedra that share corners with two equivalent O(2)Na3MgNi2 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid, corners with two equivalent O(3)Na2Ni3 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra, edges with two equivalent O(4)Na3MgNi2 octahedra, edges with two equivalent O(6)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid,  an edgeedge with one O(3)Na2Ni3 square pyramid, and edges with two equivalent O(1)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 2-5°. In the ninth O site, O(9) is bonded to one Na(2), one Na(4), one Mg(1), one Ni(3), and one Ni(4) atom to form ONa2MgNi2 square pyramids that share  a cornercorner with one O(2)Na3MgNi2 octahedra,  a cornercorner with one O(6)Na3Ni3 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid,  a cornercorner with one O(1)Na2Ni3 square pyramid, corners with three equivalent O(3)Na2Ni3 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra, edges with two equivalent O(4)Na3MgNi2 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid, and  an edgeedge with one O(7)Na2MgNi2 square pyramid. The corner-sharing octahedral tilt angles range from 3-5°. In the tenth O site, O(10) is bonded to one Na(2), one Na(3), one Mg(1), one Ni(2), and one Ni(4) atom to form ONa2MgNi2 square pyramids that share  a cornercorner with one O(8)Na3Ni3 octahedra, corners with two equivalent O(4)Na3MgNi2 octahedra,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid,  a cornercorner with one O(3)Na2Ni3 square pyramid, corners with two equivalent O(1)Na2Ni3 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid, and  an edgeedge with one O(3)Na2Ni3 square pyramid. The corner-sharing octahedral tilt angles range from 4-9°. is represented by the CIF card [CIF]
data_Na4Mg(Ni2O5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.022
_cell_length_b   6.367
_cell_length_c   7.040
_cell_angle_alpha   109.568
_cell_angle_beta   96.467
_cell_angle_gamma   104.424
_symmetry_Int_Tables_number   1
_cell_volume   200.616
_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  0.369  0.283  0.749  1.0
  Na  Na1  1  0.574  0.717  0.177  1.0
  Na  Na2  1  0.781  0.090  0.548  1.0
  Na  Na3  1  0.982  0.521  0.988  1.0
  Mg  Mg4  1  0.181  0.404  0.363  1.0
  Ni  Ni5  1  0.377  0.799  0.764  1.0
  Ni  Ni6  1  0.977  0.002  0.962  1.0
  Ni  Ni7  1  0.776  0.601  0.568  1.0
  Ni  Ni8  1  0.577  0.209  0.162  1.0
  O  O9  1  0.069  0.907  0.694  1.0
  O  O10  1  0.082  0.502  0.658  1.0
  O  O11  1  0.287  0.886  0.029  1.0
  O  O12  1  0.290  0.327  0.080  1.0
  O  O13  1  0.489  0.725  0.506  1.0
  O  O14  1  0.662  0.672  0.829  1.0
  O  O15  1  0.517  0.303  0.458  1.0
  O  O16  1  0.662  0.099  0.869  1.0
  O  O17  1  0.858  0.534  0.303  1.0
  O  O18  1  0.869  0.083  0.222  1.0
[/CIF]
.
The crystal structure described by Na4Mg(Ni2O5)2 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(8) atom to form distorted NaO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-19°. In the second Na site, Na(2) is bonded to one O(10), one O(3), one O(4), one O(5), one O(6), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-21°. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(2), one O(5), one O(7), and one O(8) atom. In the fourth Na site, Na(4) is bonded to one O(2), one O(3), one O(4), one O(6), one O(8), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Ni(3)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-19°. Mg(1) is bonded to one O(10), one O(2), one O(4), one O(5), one O(7), and one O(9) atom to form MgO6 octahedra that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one Na(4)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-21°. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with two equivalent Na(4)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. In the second Ni site, Ni(2) is bonded to one O(1), one O(10), one O(3), one O(4), one O(6), and one O(8) atom to form NiO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-18°. In the third Ni site, Ni(3) is bonded to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra,  a cornercorner with one Na(4)O6 octahedra, corners with two equivalent Na(1)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-17°. In the fourth Ni site, Ni(4) is bonded to one O(10), one O(3), one O(4), one O(7), one O(8), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Na(1)O6 octahedra, corners with two equivalent Na(4)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-19°. There are ten inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(3), one Ni(1), one Ni(2), and one Ni(3) atom to form ONa2Ni3 square pyramids that share corners with two equivalent O(6)Na3Ni3 octahedra,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid, corners with two equivalent O(10)Na2MgNi2 square pyramids, corners with three equivalent O(7)Na2MgNi2 square pyramids,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra, edges with two equivalent O(2)Na3MgNi2 octahedra, edges with two equivalent O(8)Na3Ni3 octahedra,  an edgeedge with one O(5)Na2MgNi2 square pyramid, and  an edgeedge with one O(3)Na2Ni3 square pyramid. The corner-sharing octahedral tilt angles are 4°. In the second O site, O(2) is bonded to one Na(1), one Na(3), one Na(4), one Mg(1), one Ni(1), and one Ni(3) atom to form distorted ONa3MgNi2 octahedra that share  a cornercorner with one O(4)Na3MgNi2 octahedra, corners with two equivalent O(8)Na3Ni3 octahedra,  a cornercorner with one O(9)Na2MgNi2 square pyramid, corners with two equivalent O(5)Na2MgNi2 square pyramids,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra, edges with two equivalent O(6)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid,  an edgeedge with one O(3)Na2Ni3 square pyramid, edges with two equivalent O(7)Na2MgNi2 square pyramids, and edges with two equivalent O(1)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 2-5°. In the third O site, O(3) is bonded to one Na(2), one Na(4), one Ni(1), one Ni(2), and one Ni(4) atom to form ONa2Ni3 square pyramids that share corners with two equivalent O(8)Na3Ni3 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid, corners with two equivalent O(5)Na2MgNi2 square pyramids, corners with three equivalent O(9)Na2MgNi2 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra, edges with two equivalent O(4)Na3MgNi2 octahedra, edges with two equivalent O(6)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid, and  an edgeedge with one O(1)Na2Ni3 square pyramid. The corner-sharing octahedral tilt angles range from 5-11°. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Na(4), one Mg(1), one Ni(2), and one Ni(4) atom to form ONa3MgNi2 octahedra that share  a cornercorner with one O(2)Na3MgNi2 octahedra, corners with two equivalent O(6)Na3Ni3 octahedra,  a cornercorner with one O(7)Na2MgNi2 square pyramid, corners with two equivalent O(10)Na2MgNi2 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra, edges with two equivalent O(8)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(1)Na2Ni3 square pyramid, edges with two equivalent O(9)Na2MgNi2 square pyramids, and edges with two equivalent O(3)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 3-11°. In the fifth O site, O(5) is bonded to one Na(2), one Na(3), one Mg(1), one Ni(1), and one Ni(3) atom to form ONa2MgNi2 square pyramids that share  a cornercorner with one O(6)Na3Ni3 octahedra, corners with two equivalent O(2)Na3MgNi2 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid,  a cornercorner with one O(1)Na2Ni3 square pyramid, corners with two equivalent O(3)Na2Ni3 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid, and  an edgeedge with one O(1)Na2Ni3 square pyramid. The corner-sharing octahedral tilt angles range from 5-10°. In the sixth O site, O(6) is bonded to one Na(1), one Na(2), one Na(4), one Ni(1), one Ni(2), and one Ni(3) atom to form distorted ONa3Ni3 octahedra that share corners with two equivalent O(4)Na3MgNi2 octahedra,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid, corners with two equivalent O(1)Na2Ni3 square pyramids,  an edgeedge with one O(4)Na3MgNi2 octahedra, edges with two equivalent O(2)Na3MgNi2 octahedra, edges with two equivalent O(8)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid,  an edgeedge with one O(1)Na2Ni3 square pyramid, and edges with two equivalent O(3)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 3-11°. In the seventh O site, O(7) is bonded to one Na(1), one Na(3), one Mg(1), one Ni(3), and one Ni(4) atom to form ONa2MgNi2 square pyramids that share  a cornercorner with one O(4)Na3MgNi2 octahedra,  a cornercorner with one O(8)Na3Ni3 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid,  a cornercorner with one O(3)Na2Ni3 square pyramid, corners with three equivalent O(1)Na2Ni3 square pyramids,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra, edges with two equivalent O(2)Na3MgNi2 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid, and  an edgeedge with one O(9)Na2MgNi2 square pyramid. The corner-sharing octahedral tilt angles range from 5-11°. In the eighth O site, O(8) is bonded to one Na(1), one Na(3), one Na(4), one Ni(1), one Ni(2), and one Ni(4) atom to form distorted ONa3Ni3 octahedra that share corners with two equivalent O(2)Na3MgNi2 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid, corners with two equivalent O(3)Na2Ni3 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra, edges with two equivalent O(4)Na3MgNi2 octahedra, edges with two equivalent O(6)Na3Ni3 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid,  an edgeedge with one O(3)Na2Ni3 square pyramid, and edges with two equivalent O(1)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 2-5°. In the ninth O site, O(9) is bonded to one Na(2), one Na(4), one Mg(1), one Ni(3), and one Ni(4) atom to form ONa2MgNi2 square pyramids that share  a cornercorner with one O(2)Na3MgNi2 octahedra,  a cornercorner with one O(6)Na3Ni3 octahedra,  a cornercorner with one O(10)Na2MgNi2 square pyramid,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid,  a cornercorner with one O(1)Na2Ni3 square pyramid, corners with three equivalent O(3)Na2Ni3 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra, edges with two equivalent O(4)Na3MgNi2 octahedra,  an edgeedge with one O(10)Na2MgNi2 square pyramid,  an edgeedge with one O(5)Na2MgNi2 square pyramid, and  an edgeedge with one O(7)Na2MgNi2 square pyramid. The corner-sharing octahedral tilt angles range from 3-5°. In the tenth O site, O(10) is bonded to one Na(2), one Na(3), one Mg(1), one Ni(2), and one Ni(4) atom to form ONa2MgNi2 square pyramids that share  a cornercorner with one O(8)Na3Ni3 octahedra, corners with two equivalent O(4)Na3MgNi2 octahedra,  a cornercorner with one O(5)Na2MgNi2 square pyramid,  a cornercorner with one O(7)Na2MgNi2 square pyramid,  a cornercorner with one O(9)Na2MgNi2 square pyramid,  a cornercorner with one O(3)Na2Ni3 square pyramid, corners with two equivalent O(1)Na2Ni3 square pyramids,  an edgeedge with one O(2)Na3MgNi2 octahedra,  an edgeedge with one O(4)Na3MgNi2 octahedra,  an edgeedge with one O(6)Na3Ni3 octahedra,  an edgeedge with one O(8)Na3Ni3 octahedra,  an edgeedge with one O(5)Na2MgNi2 square pyramid,  an edgeedge with one O(7)Na2MgNi2 square pyramid,  an edgeedge with one O(9)Na2MgNi2 square pyramid, and  an edgeedge with one O(3)Na2Ni3 square pyramid. The corner-sharing octahedral tilt angles range from 4-9°. is represented by the CIF card [CIF]
data_Na4Mg(Ni2O5)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.022
_cell_length_b   6.367
_cell_length_c   7.040
_cell_angle_alpha   109.568
_cell_angle_beta   96.467
_cell_angle_gamma   104.424
_symmetry_Int_Tables_number   1
_cell_volume   200.616
_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  0.369  0.283  0.749  1.0
  Na  Na1  1  0.574  0.717  0.177  1.0
  Na  Na2  1  0.781  0.090  0.548  1.0
  Na  Na3  1  0.982  0.521  0.988  1.0
  Mg  Mg4  1  0.181  0.404  0.363  1.0
  Ni  Ni5  1  0.377  0.799  0.764  1.0
  Ni  Ni6  1  0.977  0.002  0.962  1.0
  Ni  Ni7  1  0.776  0.601  0.568  1.0
  Ni  Ni8  1  0.577  0.209  0.162  1.0
  O  O9  1  0.069  0.907  0.694  1.0
  O  O10  1  0.082  0.502  0.658  1.0
  O  O11  1  0.287  0.886  0.029  1.0
  O  O12  1  0.290  0.327  0.080  1.0
  O  O13  1  0.489  0.725  0.506  1.0
  O  O14  1  0.662  0.672  0.829  1.0
  O  O15  1  0.517  0.303  0.458  1.0
  O  O16  1  0.662  0.099  0.869  1.0
  O  O17  1  0.858  0.534  0.303  1.0
  O  O18  1  0.869  0.083  0.222  1.0
[/CIF]
.