The crystal structure described by NaNi2O3 is Caswellsilverite-like structured and crystallizes in the monoclinic P2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with two equivalent Ni(2)O6 octahedra, corners with four equivalent Ni(6)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, and edges with two equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with two equivalent Ni(3)O6 octahedra, corners with four equivalent Ni(5)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, and edges with two equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. There are six inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(3)O6 octahedra, corners with four equivalent Ni(5)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-14°. In the second Ni site, Ni(2) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(4)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, edges with two equivalent Ni(6)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-7°. In the third Ni site, Ni(3) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-8°. In the fourth Ni site, Ni(4) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(2)O6 octahedra, corners with four equivalent Ni(6)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-13°. In the fifth Ni site, Ni(5) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, and edges with two equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-14°. In the sixth Ni site, Ni(6) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(4)O6 octahedra, corners with four equivalent Na(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-13°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(2), one Ni(2), one Ni(4), and two equivalent Ni(5) atoms to form a mixture of edge and corner-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the second O site, O(2) is bonded to two equivalent Na(1), one Ni(1), one Ni(3), and two equivalent Ni(6) atoms to form a mixture of edge and corner-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Ni(2), one Ni(4), one Ni(5), and one Ni(6) atom to form a mixture of edge and corner-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(3), one Ni(5), and one Ni(6) atom to form a mixture of edge and corner-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. is represented by the CIF file [CIF]
data_NaNi2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.216
_cell_length_b   5.216
_cell_length_c   5.338
_cell_angle_alpha   99.977
_cell_angle_beta   99.979
_cell_angle_gamma   119.366
_symmetry_Int_Tables_number   1
_cell_volume   118.897
_cell_formula_units_Z   2
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  0.830  0.170  0.500  1.0
  Na  Na1  1  0.170  0.830  0.500  1.0
  Ni  Ni2  1  0.500  0.500  0.500  1.0
  Ni  Ni3  1  0.000  0.000  0.000  1.0
  Ni  Ni4  1  0.336  0.664  0.000  1.0
  Ni  Ni5  1  0.664  0.336  1.000  1.0
  O  O6  1  0.285  0.285  0.761  1.0
  O  O7  1  0.715  0.715  0.239  1.0
  O  O8  1  0.914  0.612  0.791  1.0
  O  O9  1  0.612  0.914  0.791  1.0
  O  O10  1  0.086  0.388  0.209  1.0
  O  O11  1  0.388  0.086  0.209  1.0
[/CIF]
.
The crystal structure described by NaNi2O3 is Caswellsilverite-like structured and crystallizes in the monoclinic P2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with two equivalent Ni(2)O6 octahedra, corners with four equivalent Ni(6)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, and edges with two equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. In the second Na site, Na(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with two equivalent Ni(3)O6 octahedra, corners with four equivalent Ni(5)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, and edges with two equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. There are six inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(3)O6 octahedra, corners with four equivalent Ni(5)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-14°. In the second Ni site, Ni(2) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(4)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, edges with two equivalent Ni(6)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-7°. In the third Ni site, Ni(3) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-8°. In the fourth Ni site, Ni(4) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(2)O6 octahedra, corners with four equivalent Ni(6)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-13°. In the fifth Ni site, Ni(5) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with four equivalent Na(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, and edges with two equivalent Ni(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-14°. In the sixth Ni site, Ni(6) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ni(4)O6 octahedra, corners with four equivalent Na(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-13°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(2), one Ni(2), one Ni(4), and two equivalent Ni(5) atoms to form a mixture of edge and corner-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the second O site, O(2) is bonded to two equivalent Na(1), one Ni(1), one Ni(3), and two equivalent Ni(6) atoms to form a mixture of edge and corner-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Ni(2), one Ni(4), one Ni(5), and one Ni(6) atom to form a mixture of edge and corner-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. In the fourth O site, O(4) is bonded to one Na(1), one Na(2), one Ni(1), one Ni(3), one Ni(5), and one Ni(6) atom to form a mixture of edge and corner-sharing ONa2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-8°. is represented by the CIF file [CIF]
data_NaNi2O3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.216
_cell_length_b   5.216
_cell_length_c   5.338
_cell_angle_alpha   99.977
_cell_angle_beta   99.979
_cell_angle_gamma   119.366
_symmetry_Int_Tables_number   1
_cell_volume   118.897
_cell_formula_units_Z   2
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  0.830  0.170  0.500  1.0
  Na  Na1  1  0.170  0.830  0.500  1.0
  Ni  Ni2  1  0.500  0.500  0.500  1.0
  Ni  Ni3  1  0.000  0.000  0.000  1.0
  Ni  Ni4  1  0.336  0.664  0.000  1.0
  Ni  Ni5  1  0.664  0.336  1.000  1.0
  O  O6  1  0.285  0.285  0.761  1.0
  O  O7  1  0.715  0.715  0.239  1.0
  O  O8  1  0.914  0.612  0.791  1.0
  O  O9  1  0.612  0.914  0.791  1.0
  O  O10  1  0.086  0.388  0.209  1.0
  O  O11  1  0.388  0.086  0.209  1.0
[/CIF]
.