The crystal structure described by Ca(NiO2)2 is Spinel-like structured and crystallizes in the orthorhombic Imma space group. Ca(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CaO6 octahedra that share corners with six equivalent Ni(1)O4 tetrahedra, edges with two equivalent Ca(1)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NiO4 tetrahedra that share corners with six equivalent Ca(1)O6 octahedra and corners with six equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-59°. In the second Ni site, Ni(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with six equivalent Ni(1)O4 tetrahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with four equivalent Ca(1)O6 octahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Ca(1), one Ni(1), and one Ni(2) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Ni(1), and two equivalent Ni(2) atoms. is represented by the CIF file [CIF]
data_Ca(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.108
_cell_length_b   6.108
_cell_length_c   6.108
_cell_angle_alpha   118.901
_cell_angle_beta   118.735
_cell_angle_gamma   92.060
_symmetry_Int_Tables_number   1
_cell_volume   163.923
_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
  Ca  Ca0  1  0.500  0.000  0.000  1.0
  Ca  Ca1  1  0.500  0.500  0.500  1.0
  Ni  Ni2  1  0.889  0.139  0.750  1.0
  Ni  Ni3  1  0.111  0.861  0.250  1.0
  Ni  Ni4  1  0.500  0.500  0.000  1.0
  Ni  Ni5  1  0.000  0.500  0.500  1.0
  O  O6  1  0.738  0.728  0.010  1.0
  O  O7  1  0.233  0.724  0.991  1.0
  O  O8  1  0.218  0.728  0.490  1.0
  O  O9  1  0.233  0.242  0.509  1.0
  O  O10  1  0.767  0.758  0.491  1.0
  O  O11  1  0.767  0.276  0.009  1.0
  O  O12  1  0.782  0.272  0.510  1.0
  O  O13  1  0.262  0.272  0.990  1.0
[/CIF]
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The crystal structure described by Ca(NiO2)2 is Spinel-like structured and crystallizes in the orthorhombic Imma space group. Ca(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form CaO6 octahedra that share corners with six equivalent Ni(1)O4 tetrahedra, edges with two equivalent Ca(1)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form NiO4 tetrahedra that share corners with six equivalent Ca(1)O6 octahedra and corners with six equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-59°. In the second Ni site, Ni(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with six equivalent Ni(1)O4 tetrahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with four equivalent Ca(1)O6 octahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Ca(1), one Ni(1), and one Ni(2) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Ca(1), one Ni(1), and two equivalent Ni(2) atoms. is represented by the CIF file [CIF]
data_Ca(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.108
_cell_length_b   6.108
_cell_length_c   6.108
_cell_angle_alpha   118.901
_cell_angle_beta   118.735
_cell_angle_gamma   92.060
_symmetry_Int_Tables_number   1
_cell_volume   163.923
_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
  Ca  Ca0  1  0.500  0.000  0.000  1.0
  Ca  Ca1  1  0.500  0.500  0.500  1.0
  Ni  Ni2  1  0.889  0.139  0.750  1.0
  Ni  Ni3  1  0.111  0.861  0.250  1.0
  Ni  Ni4  1  0.500  0.500  0.000  1.0
  Ni  Ni5  1  0.000  0.500  0.500  1.0
  O  O6  1  0.738  0.728  0.010  1.0
  O  O7  1  0.233  0.724  0.991  1.0
  O  O8  1  0.218  0.728  0.490  1.0
  O  O9  1  0.233  0.242  0.509  1.0
  O  O10  1  0.767  0.758  0.491  1.0
  O  O11  1  0.767  0.276  0.009  1.0
  O  O12  1  0.782  0.272  0.510  1.0
  O  O13  1  0.262  0.272  0.990  1.0
[/CIF]
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