The material described by NiO2 crystallizes in the triclinic P1 space group. There are twelve inequivalent Ni sites. In the first Ni site, Ni(1) 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 NiO6 octahedra that share  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ni(7)O4 tetrahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the second Ni site, Ni(2) is bonded to one O(1), one O(12), one O(2), one O(4), one O(6), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ni(7)O4 tetrahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the third Ni site, Ni(3) is bonded to one O(10), one O(11), one O(14), one O(15), one O(17), and one O(7) atom to form NiO6 octahedra that share  a cornercorner with one Ni(7)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, and edges with two equivalent Ni(9)O6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(1), one O(12), one O(2), one O(3), one O(8), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ni(7)O4 tetrahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. In the fifth Ni site, Ni(5) is bonded to one O(11), one O(14), one O(17), one O(20), one O(5), and one O(7) atom to form NiO6 octahedra that share  a cornercorner with one Ni(7)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(9)O6 octahedra. In the sixth Ni site, Ni(6) is bonded to one O(13), one O(14), one O(15), one O(18), one O(19), and one O(20) atom to form edge-sharing NiO6 octahedra. In the seventh Ni site, Ni(7) is bonded to one O(12), one O(17), one O(6), and one O(8) atom to form corner-sharing NiO4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-59°. In the eighth Ni site, Ni(8) is bonded to one O(16), one O(18), one O(19), one O(21), one O(22), and one O(23) atom to form NiO6 octahedra that share corners with two equivalent Ni(12)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(10)O6 octahedra, and edges with two equivalent Ni(11)O6 octahedra. In the ninth Ni site, Ni(9) is bonded to one O(10), one O(15), one O(17), one O(20), one O(5), and one O(7) atom to form NiO6 octahedra that share  a cornercorner with one Ni(7)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(5)O6 octahedra. In the tenth Ni site, Ni(10) is bonded to one O(13), one O(16), one O(19), one O(21), one O(23), and one O(24) atom to form NiO6 octahedra that share corners with two equivalent Ni(12)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(11)O6 octahedra, and edges with two equivalent Ni(8)O6 octahedra. In the eleventh Ni site, Ni(11) is bonded to one O(13), one O(16), one O(18), one O(22), one O(23), and one O(24) atom to form NiO6 octahedra that share corners with two equivalent Ni(12)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(10)O6 octahedra, and edges with two equivalent Ni(8)O6 octahedra. In the twelfth Ni site, Ni(12) is bonded to one O(21), one O(22), one O(24), and one O(9) atom to form corner-sharing NiO4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-59°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Ni(2) and one Ni(4) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ni(1), one Ni(2), and one Ni(4) atom. In the third O site, O(3) is bonded in a water-like geometry to one Ni(1) and one Ni(4) atom. In the fourth O site, O(4) is bonded in a water-like geometry to one Ni(1) and one Ni(2) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one Ni(5) and one Ni(9) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Ni(1), one Ni(2), and one Ni(7) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Ni(3), one Ni(5), and one Ni(9) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ni(1), one Ni(4), and one Ni(7) atom. In the ninth O site, O(9) is bonded in a distorted trigonal pyramidal geometry to one Ni(1), one Ni(12), one Ni(2), and one Ni(4) atom. In the tenth O site, O(10) is bonded in a water-like geometry to one Ni(3) and one Ni(9) atom. In the eleventh O site, O(11) is bonded in a water-like geometry to one Ni(3) and one Ni(5) atom. In the twelfth O site, O(12) is bonded in a trigonal planar geometry to one Ni(2), one Ni(4), and one Ni(7) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Ni(10), one Ni(11), and one Ni(6) atom. In the fourteenth O site, O(14) is bonded in a distorted T-shaped geometry to one Ni(3), one Ni(5), and one Ni(6) atom. In the fifteenth O site, O(15) is bonded in a distorted T-shaped geometry to one Ni(3), one Ni(6), and one Ni(9) atom. In the sixteenth O site, O(16) is bonded in a distorted T-shaped geometry to one Ni(10), one Ni(11), and one Ni(8) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal pyramidal geometry to one Ni(3), one Ni(5), one Ni(7), and one Ni(9) atom. In the eighteenth O site, O(18) is bonded in a distorted T-shaped geometry to one Ni(11), one Ni(6), and one Ni(8) atom. In the nineteenth O site, O(19) is bonded in a distorted T-shaped geometry to one Ni(10), one Ni(6), and one Ni(8) atom. In the twentieth O site, O(20) is bonded in a distorted T-shaped geometry to one Ni(5), one Ni(6), and one Ni(9) atom. In the twenty-first O site, O(21) is bonded in a trigonal planar geometry to one Ni(10), one Ni(12), and one Ni(8) atom. In the twenty-second O site, O(22) is bonded in a trigonal planar geometry to one Ni(11), one Ni(12), and one Ni(8) atom. In the twenty-third O site, O(23) is bonded in a distorted T-shaped geometry to one Ni(10), one Ni(11), and one Ni(8) atom. In the twenty-fourth O site, O(24) is bonded in a trigonal planar geometry to one Ni(10), one Ni(11), and one Ni(12) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_NiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.612
_cell_length_b   5.610
_cell_length_c   17.215
_cell_angle_alpha   60.567
_cell_angle_beta   60.509
_cell_angle_gamma   60.019
_symmetry_Int_Tables_number   1
_cell_volume   386.384
_cell_formula_units_Z   12
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
  Ni  Ni0  1  0.498  0.497  0.167  1.0
  Ni  Ni1  1  0.498  0.002  0.167  1.0
  Ni  Ni2  1  0.494  0.494  0.505  1.0
  Ni  Ni3  1  0.004  0.497  0.167  1.0
  Ni  Ni4  1  0.494  0.998  0.505  1.0
  Ni  Ni5  1  0.499  0.500  0.667  1.0
  Ni  Ni6  1  0.875  0.875  0.291  1.0
  Ni  Ni7  1  0.503  0.504  0.829  1.0
  Ni  Ni8  1  0.998  0.494  0.505  1.0
  Ni  Ni9  1  0.504  0.004  0.829  1.0
  Ni  Ni10  1  0.003  0.504  0.829  1.0
  Ni  Ni11  1  0.880  0.881  0.951  1.0
  O  O12  1  0.257  0.256  0.096  1.0
  O  O13  1  0.264  0.263  0.236  1.0
  O  O14  1  0.258  0.700  0.095  1.0
  O  O15  1  0.701  0.258  0.095  1.0
  O  O16  1  0.255  0.254  0.432  1.0
  O  O17  1  0.286  0.751  0.237  1.0
  O  O18  1  0.260  0.261  0.573  1.0
  O  O19  1  0.752  0.286  0.237  1.0
  O  O20  1  0.738  0.736  0.097  1.0
  O  O21  1  0.255  0.697  0.432  1.0
  O  O22  1  0.697  0.255  0.432  1.0
  O  O23  1  0.753  0.752  0.236  1.0
  O  O24  1  0.265  0.265  0.753  1.0
  O  O25  1  0.288  0.734  0.581  1.0
  O  O26  1  0.734  0.289  0.581  1.0
  O  O27  1  0.268  0.269  0.897  1.0
  O  O28  1  0.732  0.732  0.435  1.0
  O  O29  1  0.265  0.710  0.753  1.0
  O  O30  1  0.710  0.266  0.753  1.0
  O  O31  1  0.735  0.735  0.581  1.0
  O  O32  1  0.292  0.751  0.902  1.0
  O  O33  1  0.750  0.293  0.901  1.0
  O  O34  1  0.738  0.738  0.762  1.0
  O  O35  1  0.751  0.752  0.901  1.0
[/CIF]
.
The material described by NiO2 crystallizes in the triclinic P1 space group. There are twelve inequivalent Ni sites. In the first Ni site, Ni(1) 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 NiO6 octahedra that share  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ni(7)O4 tetrahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the second Ni site, Ni(2) is bonded to one O(1), one O(12), one O(2), one O(4), one O(6), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ni(7)O4 tetrahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the third Ni site, Ni(3) is bonded to one O(10), one O(11), one O(14), one O(15), one O(17), and one O(7) atom to form NiO6 octahedra that share  a cornercorner with one Ni(7)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, and edges with two equivalent Ni(9)O6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(1), one O(12), one O(2), one O(3), one O(8), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ni(7)O4 tetrahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. In the fifth Ni site, Ni(5) is bonded to one O(11), one O(14), one O(17), one O(20), one O(5), and one O(7) atom to form NiO6 octahedra that share  a cornercorner with one Ni(7)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(9)O6 octahedra. In the sixth Ni site, Ni(6) is bonded to one O(13), one O(14), one O(15), one O(18), one O(19), and one O(20) atom to form edge-sharing NiO6 octahedra. In the seventh Ni site, Ni(7) is bonded to one O(12), one O(17), one O(6), and one O(8) atom to form corner-sharing NiO4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-59°. In the eighth Ni site, Ni(8) is bonded to one O(16), one O(18), one O(19), one O(21), one O(22), and one O(23) atom to form NiO6 octahedra that share corners with two equivalent Ni(12)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(10)O6 octahedra, and edges with two equivalent Ni(11)O6 octahedra. In the ninth Ni site, Ni(9) is bonded to one O(10), one O(15), one O(17), one O(20), one O(5), and one O(7) atom to form NiO6 octahedra that share  a cornercorner with one Ni(7)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(5)O6 octahedra. In the tenth Ni site, Ni(10) is bonded to one O(13), one O(16), one O(19), one O(21), one O(23), and one O(24) atom to form NiO6 octahedra that share corners with two equivalent Ni(12)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(11)O6 octahedra, and edges with two equivalent Ni(8)O6 octahedra. In the eleventh Ni site, Ni(11) is bonded to one O(13), one O(16), one O(18), one O(22), one O(23), and one O(24) atom to form NiO6 octahedra that share corners with two equivalent Ni(12)O4 tetrahedra,  an edgeedge with one Ni(6)O6 octahedra, edges with two equivalent Ni(10)O6 octahedra, and edges with two equivalent Ni(8)O6 octahedra. In the twelfth Ni site, Ni(12) is bonded to one O(21), one O(22), one O(24), and one O(9) atom to form corner-sharing NiO4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-59°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Ni(2) and one Ni(4) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ni(1), one Ni(2), and one Ni(4) atom. In the third O site, O(3) is bonded in a water-like geometry to one Ni(1) and one Ni(4) atom. In the fourth O site, O(4) is bonded in a water-like geometry to one Ni(1) and one Ni(2) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one Ni(5) and one Ni(9) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Ni(1), one Ni(2), and one Ni(7) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Ni(3), one Ni(5), and one Ni(9) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ni(1), one Ni(4), and one Ni(7) atom. In the ninth O site, O(9) is bonded in a distorted trigonal pyramidal geometry to one Ni(1), one Ni(12), one Ni(2), and one Ni(4) atom. In the tenth O site, O(10) is bonded in a water-like geometry to one Ni(3) and one Ni(9) atom. In the eleventh O site, O(11) is bonded in a water-like geometry to one Ni(3) and one Ni(5) atom. In the twelfth O site, O(12) is bonded in a trigonal planar geometry to one Ni(2), one Ni(4), and one Ni(7) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Ni(10), one Ni(11), and one Ni(6) atom. In the fourteenth O site, O(14) is bonded in a distorted T-shaped geometry to one Ni(3), one Ni(5), and one Ni(6) atom. In the fifteenth O site, O(15) is bonded in a distorted T-shaped geometry to one Ni(3), one Ni(6), and one Ni(9) atom. In the sixteenth O site, O(16) is bonded in a distorted T-shaped geometry to one Ni(10), one Ni(11), and one Ni(8) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal pyramidal geometry to one Ni(3), one Ni(5), one Ni(7), and one Ni(9) atom. In the eighteenth O site, O(18) is bonded in a distorted T-shaped geometry to one Ni(11), one Ni(6), and one Ni(8) atom. In the nineteenth O site, O(19) is bonded in a distorted T-shaped geometry to one Ni(10), one Ni(6), and one Ni(8) atom. In the twentieth O site, O(20) is bonded in a distorted T-shaped geometry to one Ni(5), one Ni(6), and one Ni(9) atom. In the twenty-first O site, O(21) is bonded in a trigonal planar geometry to one Ni(10), one Ni(12), and one Ni(8) atom. In the twenty-second O site, O(22) is bonded in a trigonal planar geometry to one Ni(11), one Ni(12), and one Ni(8) atom. In the twenty-third O site, O(23) is bonded in a distorted T-shaped geometry to one Ni(10), one Ni(11), and one Ni(8) atom. In the twenty-fourth O site, O(24) is bonded in a trigonal planar geometry to one Ni(10), one Ni(11), and one Ni(12) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_NiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.612
_cell_length_b   5.610
_cell_length_c   17.215
_cell_angle_alpha   60.567
_cell_angle_beta   60.509
_cell_angle_gamma   60.019
_symmetry_Int_Tables_number   1
_cell_volume   386.384
_cell_formula_units_Z   12
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
  Ni  Ni0  1  0.498  0.497  0.167  1.0
  Ni  Ni1  1  0.498  0.002  0.167  1.0
  Ni  Ni2  1  0.494  0.494  0.505  1.0
  Ni  Ni3  1  0.004  0.497  0.167  1.0
  Ni  Ni4  1  0.494  0.998  0.505  1.0
  Ni  Ni5  1  0.499  0.500  0.667  1.0
  Ni  Ni6  1  0.875  0.875  0.291  1.0
  Ni  Ni7  1  0.503  0.504  0.829  1.0
  Ni  Ni8  1  0.998  0.494  0.505  1.0
  Ni  Ni9  1  0.504  0.004  0.829  1.0
  Ni  Ni10  1  0.003  0.504  0.829  1.0
  Ni  Ni11  1  0.880  0.881  0.951  1.0
  O  O12  1  0.257  0.256  0.096  1.0
  O  O13  1  0.264  0.263  0.236  1.0
  O  O14  1  0.258  0.700  0.095  1.0
  O  O15  1  0.701  0.258  0.095  1.0
  O  O16  1  0.255  0.254  0.432  1.0
  O  O17  1  0.286  0.751  0.237  1.0
  O  O18  1  0.260  0.261  0.573  1.0
  O  O19  1  0.752  0.286  0.237  1.0
  O  O20  1  0.738  0.736  0.097  1.0
  O  O21  1  0.255  0.697  0.432  1.0
  O  O22  1  0.697  0.255  0.432  1.0
  O  O23  1  0.753  0.752  0.236  1.0
  O  O24  1  0.265  0.265  0.753  1.0
  O  O25  1  0.288  0.734  0.581  1.0
  O  O26  1  0.734  0.289  0.581  1.0
  O  O27  1  0.268  0.269  0.897  1.0
  O  O28  1  0.732  0.732  0.435  1.0
  O  O29  1  0.265  0.710  0.753  1.0
  O  O30  1  0.710  0.266  0.753  1.0
  O  O31  1  0.735  0.735  0.581  1.0
  O  O32  1  0.292  0.751  0.902  1.0
  O  O33  1  0.750  0.293  0.901  1.0
  O  O34  1  0.738  0.738  0.762  1.0
  O  O35  1  0.751  0.752  0.901  1.0
[/CIF]
.