The material structure described by Ba(NiO2)4 crystallizes in the trigonal R-3m space group. Ba(1) is bonded in a hexagonal planar geometry to three equivalent O(3) and three equivalent O(4) atoms. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form edge-sharing NiO6 octahedra. In the second Ni site, Ni(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form edge-sharing NiO6 octahedra. In the third Ni site, Ni(3) is bonded to six equivalent O(4) atoms to form edge-sharing NiO6 octahedra. In the fourth Ni site, Ni(4) is bonded to six equivalent O(3) atoms to form edge-sharing NiO6 octahedra. There are four inequivalent O sites. In the first O site, O(3) is bonded in a 4-coordinate geometry to one Ba(1), one Ni(4), and two equivalent Ni(2) atoms. In the second O site, O(4) is bonded in a 4-coordinate geometry to one Ba(1), one Ni(3), and two equivalent Ni(1) atoms. In the third O site, O(1) is bonded in a distorted T-shaped geometry to three equivalent Ni(1) atoms. In the fourth O site, O(2) is bonded in a distorted T-shaped geometry to three equivalent Ni(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba(NiO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.735
_cell_length_b   5.735
_cell_length_c   7.207
_cell_angle_alpha   113.447
_cell_angle_beta   113.443
_cell_angle_gamma   60.005
_symmetry_Int_Tables_number   1
_cell_volume   182.341
_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
  Ba  Ba0  1  0.500  0.500  0.500  1.0
  Ni  Ni1  1  0.500  0.500  1.000  1.0
  Ni  Ni2  1  1.000  0.500  1.000  1.0
  Ni  Ni3  1  0.500  1.000  1.000  1.0
  Ni  Ni4  1  0.000  1.000  1.000  1.0
  O  O5  1  0.283  0.283  0.849  1.0
  O  O6  1  0.717  0.717  0.151  1.0
  O  O7  1  0.771  0.771  0.844  1.0
  O  O8  1  0.698  0.229  0.156  1.0
  O  O9  1  0.229  0.229  0.156  1.0
  O  O10  1  0.229  0.698  0.156  1.0
  O  O11  1  0.302  0.771  0.844  1.0
  O  O12  1  0.771  0.302  0.844  1.0
[/CIF]
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The material structure described by Ba(NiO2)4 crystallizes in the trigonal R-3m space group. Ba(1) is bonded in a hexagonal planar geometry to three equivalent O(3) and three equivalent O(4) atoms. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form edge-sharing NiO6 octahedra. In the second Ni site, Ni(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form edge-sharing NiO6 octahedra. In the third Ni site, Ni(3) is bonded to six equivalent O(4) atoms to form edge-sharing NiO6 octahedra. In the fourth Ni site, Ni(4) is bonded to six equivalent O(3) atoms to form edge-sharing NiO6 octahedra. There are four inequivalent O sites. In the first O site, O(3) is bonded in a 4-coordinate geometry to one Ba(1), one Ni(4), and two equivalent Ni(2) atoms. In the second O site, O(4) is bonded in a 4-coordinate geometry to one Ba(1), one Ni(3), and two equivalent Ni(1) atoms. In the third O site, O(1) is bonded in a distorted T-shaped geometry to three equivalent Ni(1) atoms. In the fourth O site, O(2) is bonded in a distorted T-shaped geometry to three equivalent Ni(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba(NiO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.735
_cell_length_b   5.735
_cell_length_c   7.207
_cell_angle_alpha   113.447
_cell_angle_beta   113.443
_cell_angle_gamma   60.005
_symmetry_Int_Tables_number   1
_cell_volume   182.341
_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
  Ba  Ba0  1  0.500  0.500  0.500  1.0
  Ni  Ni1  1  0.500  0.500  1.000  1.0
  Ni  Ni2  1  1.000  0.500  1.000  1.0
  Ni  Ni3  1  0.500  1.000  1.000  1.0
  Ni  Ni4  1  0.000  1.000  1.000  1.0
  O  O5  1  0.283  0.283  0.849  1.0
  O  O6  1  0.717  0.717  0.151  1.0
  O  O7  1  0.771  0.771  0.844  1.0
  O  O8  1  0.698  0.229  0.156  1.0
  O  O9  1  0.229  0.229  0.156  1.0
  O  O10  1  0.229  0.698  0.156  1.0
  O  O11  1  0.302  0.771  0.844  1.0
  O  O12  1  0.771  0.302  0.844  1.0
[/CIF]
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