The structure described by NiO2 crystallizes in the trigonal R3m space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing NiO4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-58°. In the second Ni site, Ni(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with three equivalent Ni(1)O4 tetrahedra and edges with four equivalent Ni(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ni(1) and two equivalent Ni(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Ni(1) and three equivalent Ni(2) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to three equivalent Ni(2) atoms. In the fourth O site, O(4) is bonded in a water-like geometry to two equivalent Ni(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_NiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.685
_cell_length_b   5.685
_cell_length_c   5.685
_cell_angle_alpha   60.498
_cell_angle_beta   60.498
_cell_angle_gamma   60.498
_symmetry_Int_Tables_number   1
_cell_volume   131.407
_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
  Ni  Ni0  1  0.245  0.245  0.245  1.0
  Ni  Ni1  1  0.628  0.120  0.628  1.0
  Ni  Ni2  1  0.628  0.628  0.120  1.0
  Ni  Ni3  1  0.120  0.628  0.628  1.0
  O  O4  1  0.849  0.372  0.372  1.0
  O  O5  1  0.372  0.372  0.849  1.0
  O  O6  1  0.372  0.849  0.372  1.0
  O  O7  1  0.382  0.382  0.382  1.0
  O  O8  1  0.864  0.864  0.864  1.0
  O  O9  1  0.870  0.420  0.870  1.0
  O  O10  1  0.870  0.870  0.420  1.0
  O  O11  1  0.420  0.870  0.870  1.0
[/CIF]
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The structure described by NiO2 crystallizes in the trigonal R3m space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing NiO4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-58°. In the second Ni site, Ni(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with three equivalent Ni(1)O4 tetrahedra and edges with four equivalent Ni(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ni(1) and two equivalent Ni(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Ni(1) and three equivalent Ni(2) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to three equivalent Ni(2) atoms. In the fourth O site, O(4) is bonded in a water-like geometry to two equivalent Ni(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_NiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.685
_cell_length_b   5.685
_cell_length_c   5.685
_cell_angle_alpha   60.498
_cell_angle_beta   60.498
_cell_angle_gamma   60.498
_symmetry_Int_Tables_number   1
_cell_volume   131.407
_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
  Ni  Ni0  1  0.245  0.245  0.245  1.0
  Ni  Ni1  1  0.628  0.120  0.628  1.0
  Ni  Ni2  1  0.628  0.628  0.120  1.0
  Ni  Ni3  1  0.120  0.628  0.628  1.0
  O  O4  1  0.849  0.372  0.372  1.0
  O  O5  1  0.372  0.372  0.849  1.0
  O  O6  1  0.372  0.849  0.372  1.0
  O  O7  1  0.382  0.382  0.382  1.0
  O  O8  1  0.864  0.864  0.864  1.0
  O  O9  1  0.870  0.420  0.870  1.0
  O  O10  1  0.870  0.870  0.420  1.0
  O  O11  1  0.420  0.870  0.870  1.0
[/CIF]
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