The structure described by Na(NiO2)2 crystallizes in the monoclinic Pc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), 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 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. 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(4), one O(5), and one O(8) atom to form edge-sharing NiO6 octahedra. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form edge-sharing NiO6 octahedra. In the third Ni site, Ni(3) is bonded to one O(1), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form edge-sharing NiO6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form edge-sharing NiO6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(2), and one Ni(3) atom to form distorted ONa2Ni3 trigonal bipyramids that share corners with two equivalent O(2)Na2Ni3 trigonal bipyramids, corners with three equivalent O(4)Na2Ni3 trigonal bipyramids,  a cornercorner with one O(5)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid, edges with two equivalent O(3)Na2Ni3 trigonal bipyramids,  an edgeedge with one O(5)NaNi3 trigonal pyramid,  an edgeedge with one O(6)NaNi3 trigonal pyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(2), and one Ni(4) atom to form distorted ONa2Ni3 trigonal bipyramids that share corners with two equivalent O(1)Na2Ni3 trigonal bipyramids, corners with three equivalent O(3)Na2Ni3 trigonal bipyramids,  a cornercorner with one O(5)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid, edges with two equivalent O(4)Na2Ni3 trigonal bipyramids,  an edgeedge with one O(5)NaNi3 trigonal pyramid,  an edgeedge with one O(6)NaNi3 trigonal pyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(2), and one Ni(4) atom to form ONa2Ni3 trigonal bipyramids that share corners with two equivalent O(4)Na2Ni3 trigonal bipyramids, corners with three equivalent O(2)Na2Ni3 trigonal bipyramids,  a cornercorner with one O(5)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid, edges with two equivalent O(1)Na2Ni3 trigonal bipyramids,  an edgeedge with one O(5)NaNi3 trigonal pyramid,  an edgeedge with one O(6)NaNi3 trigonal pyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(2), and one Ni(3) atom to form distorted ONa2Ni3 trigonal bipyramids that share corners with two equivalent O(3)Na2Ni3 trigonal bipyramids, corners with three equivalent O(1)Na2Ni3 trigonal bipyramids,  a cornercorner with one O(5)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid, edges with two equivalent O(2)Na2Ni3 trigonal bipyramids,  an edgeedge with one O(5)NaNi3 trigonal pyramid,  an edgeedge with one O(6)NaNi3 trigonal pyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the fifth O site, O(5) is bonded to one Na(2), one Ni(1), one Ni(3), and one Ni(4) atom to form distorted ONaNi3 trigonal pyramids that share  a cornercorner with one O(1)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(2)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(3)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(4)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid, corners with three equivalent O(6)NaNi3 trigonal pyramids,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the sixth O site, O(6) is bonded to one Na(2), one Ni(2), one Ni(3), and one Ni(4) atom to form distorted ONaNi3 trigonal pyramids that share  a cornercorner with one O(1)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(2)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(3)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(4)Na2Ni3 trigonal bipyramid, corners with two equivalent O(8)NaNi3 trigonal pyramids, corners with three equivalent O(5)NaNi3 trigonal pyramids,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid, and  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Na(1), one Ni(2), one Ni(3), and one Ni(4) atom. In the eighth O site, O(8) is bonded to one Na(1), one Ni(1), one Ni(3), and one Ni(4) atom to form ONaNi3 trigonal pyramids that share  a cornercorner with one O(1)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(2)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(3)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(4)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(5)NaNi3 trigonal pyramid, corners with two equivalent O(6)NaNi3 trigonal pyramids,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid, and  an edgeedge with one O(5)NaNi3 trigonal pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.847
_cell_length_b   5.688
_cell_length_c   12.577
_cell_angle_alpha   61.741
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   305.416
_cell_formula_units_Z   4
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  0.513  0.995  0.252  1.0
  Na  Na1  1  0.859  0.502  0.748  1.0
  Na  Na2  1  0.141  0.502  0.248  1.0
  Na  Na3  1  0.487  0.995  0.752  1.0
  Ni  Ni4  1  0.503  0.751  0.002  1.0
  Ni  Ni5  1  0.498  0.252  0.998  1.0
  Ni  Ni6  1  0.502  0.252  0.498  1.0
  Ni  Ni7  1  0.497  0.751  0.502  1.0
  Ni  Ni8  1  0.000  0.501  0.998  1.0
  Ni  Ni9  1  1.000  0.002  0.001  1.0
  Ni  Ni10  1  1.000  0.501  0.498  1.0
  Ni  Ni11  1  0.000  0.002  0.501  1.0
  O  O12  1  0.657  0.411  0.586  1.0
  O  O13  1  0.666  0.092  0.912  1.0
  O  O14  1  0.682  0.924  0.594  1.0
  O  O15  1  0.672  0.576  0.905  1.0
  O  O16  1  0.843  0.658  0.084  1.0
  O  O17  1  0.839  0.341  0.413  1.0
  O  O18  1  0.814  0.139  0.090  1.0
  O  O19  1  0.818  0.865  0.412  1.0
  O  O20  1  0.186  0.139  0.590  1.0
  O  O21  1  0.182  0.865  0.912  1.0
  O  O22  1  0.157  0.658  0.584  1.0
  O  O23  1  0.161  0.341  0.913  1.0
  O  O24  1  0.328  0.576  0.405  1.0
  O  O25  1  0.334  0.092  0.412  1.0
  O  O26  1  0.318  0.924  0.094  1.0
  O  O27  1  0.343  0.411  0.086  1.0
[/CIF]
.
The structure described by Na(NiO2)2 crystallizes in the monoclinic Pc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), 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 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. 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(4), one O(5), and one O(8) atom to form edge-sharing NiO6 octahedra. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form edge-sharing NiO6 octahedra. In the third Ni site, Ni(3) is bonded to one O(1), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form edge-sharing NiO6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form edge-sharing NiO6 octahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(2), and one Ni(3) atom to form distorted ONa2Ni3 trigonal bipyramids that share corners with two equivalent O(2)Na2Ni3 trigonal bipyramids, corners with three equivalent O(4)Na2Ni3 trigonal bipyramids,  a cornercorner with one O(5)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid, edges with two equivalent O(3)Na2Ni3 trigonal bipyramids,  an edgeedge with one O(5)NaNi3 trigonal pyramid,  an edgeedge with one O(6)NaNi3 trigonal pyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the second O site, O(2) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(2), and one Ni(4) atom to form distorted ONa2Ni3 trigonal bipyramids that share corners with two equivalent O(1)Na2Ni3 trigonal bipyramids, corners with three equivalent O(3)Na2Ni3 trigonal bipyramids,  a cornercorner with one O(5)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid, edges with two equivalent O(4)Na2Ni3 trigonal bipyramids,  an edgeedge with one O(5)NaNi3 trigonal pyramid,  an edgeedge with one O(6)NaNi3 trigonal pyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(2), and one Ni(4) atom to form ONa2Ni3 trigonal bipyramids that share corners with two equivalent O(4)Na2Ni3 trigonal bipyramids, corners with three equivalent O(2)Na2Ni3 trigonal bipyramids,  a cornercorner with one O(5)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid, edges with two equivalent O(1)Na2Ni3 trigonal bipyramids,  an edgeedge with one O(5)NaNi3 trigonal pyramid,  an edgeedge with one O(6)NaNi3 trigonal pyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(2), and one Ni(3) atom to form distorted ONa2Ni3 trigonal bipyramids that share corners with two equivalent O(3)Na2Ni3 trigonal bipyramids, corners with three equivalent O(1)Na2Ni3 trigonal bipyramids,  a cornercorner with one O(5)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid, edges with two equivalent O(2)Na2Ni3 trigonal bipyramids,  an edgeedge with one O(5)NaNi3 trigonal pyramid,  an edgeedge with one O(6)NaNi3 trigonal pyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the fifth O site, O(5) is bonded to one Na(2), one Ni(1), one Ni(3), and one Ni(4) atom to form distorted ONaNi3 trigonal pyramids that share  a cornercorner with one O(1)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(2)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(3)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(4)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(8)NaNi3 trigonal pyramid, corners with three equivalent O(6)NaNi3 trigonal pyramids,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid, and  an edgeedge with one O(8)NaNi3 trigonal pyramid. In the sixth O site, O(6) is bonded to one Na(2), one Ni(2), one Ni(3), and one Ni(4) atom to form distorted ONaNi3 trigonal pyramids that share  a cornercorner with one O(1)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(2)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(3)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(4)Na2Ni3 trigonal bipyramid, corners with two equivalent O(8)NaNi3 trigonal pyramids, corners with three equivalent O(5)NaNi3 trigonal pyramids,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid, and  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Na(1), one Ni(2), one Ni(3), and one Ni(4) atom. In the eighth O site, O(8) is bonded to one Na(1), one Ni(1), one Ni(3), and one Ni(4) atom to form ONaNi3 trigonal pyramids that share  a cornercorner with one O(1)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(2)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(3)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(4)Na2Ni3 trigonal bipyramid,  a cornercorner with one O(5)NaNi3 trigonal pyramid, corners with two equivalent O(6)NaNi3 trigonal pyramids,  an edgeedge with one O(1)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(2)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(3)Na2Ni3 trigonal bipyramid,  an edgeedge with one O(4)Na2Ni3 trigonal bipyramid, and  an edgeedge with one O(5)NaNi3 trigonal pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.847
_cell_length_b   5.688
_cell_length_c   12.577
_cell_angle_alpha   61.741
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   305.416
_cell_formula_units_Z   4
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  0.513  0.995  0.252  1.0
  Na  Na1  1  0.859  0.502  0.748  1.0
  Na  Na2  1  0.141  0.502  0.248  1.0
  Na  Na3  1  0.487  0.995  0.752  1.0
  Ni  Ni4  1  0.503  0.751  0.002  1.0
  Ni  Ni5  1  0.498  0.252  0.998  1.0
  Ni  Ni6  1  0.502  0.252  0.498  1.0
  Ni  Ni7  1  0.497  0.751  0.502  1.0
  Ni  Ni8  1  0.000  0.501  0.998  1.0
  Ni  Ni9  1  1.000  0.002  0.001  1.0
  Ni  Ni10  1  1.000  0.501  0.498  1.0
  Ni  Ni11  1  0.000  0.002  0.501  1.0
  O  O12  1  0.657  0.411  0.586  1.0
  O  O13  1  0.666  0.092  0.912  1.0
  O  O14  1  0.682  0.924  0.594  1.0
  O  O15  1  0.672  0.576  0.905  1.0
  O  O16  1  0.843  0.658  0.084  1.0
  O  O17  1  0.839  0.341  0.413  1.0
  O  O18  1  0.814  0.139  0.090  1.0
  O  O19  1  0.818  0.865  0.412  1.0
  O  O20  1  0.186  0.139  0.590  1.0
  O  O21  1  0.182  0.865  0.912  1.0
  O  O22  1  0.157  0.658  0.584  1.0
  O  O23  1  0.161  0.341  0.913  1.0
  O  O24  1  0.328  0.576  0.405  1.0
  O  O25  1  0.334  0.092  0.412  1.0
  O  O26  1  0.318  0.924  0.094  1.0
  O  O27  1  0.343  0.411  0.086  1.0
[/CIF]
.