The crystal structure described by K3NiO2 is Pb(Zr_(1-x)Ti_x)O3-like structured and crystallizes in the monoclinic P2_1 space group. There are six inequivalent K sites. In the first K site, K(1) is bonded in a distorted linear geometry to one O(1) and one O(3) atom. In the second K site, K(2) is bonded in a distorted linear geometry to one O(2) and one O(4) atom. In the third K site, K(3) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing KO4 tetrahedra. In the fourth K site, K(4) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing KO4 tetrahedra. In the fifth K site, K(5) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form a mixture of distorted corner and edge-sharing KO4 tetrahedra. In the sixth K site, K(6) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form a mixture of distorted corner and edge-sharing KO4 tetrahedra. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a linear geometry to one O(2) and one O(4) atom. In the second Ni site, Ni(2) is bonded in a linear geometry to one O(1) and one O(3) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one K(1), one K(5), one K(6), two equivalent K(3), and one Ni(2) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one K(2), one K(5), one K(6), two equivalent K(4), and one Ni(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one K(1), one K(5), one K(6), two equivalent K(3), and one Ni(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one K(2), one K(5), one K(6), two equivalent K(4), and one Ni(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K3NiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.094
_cell_length_b   6.095
_cell_length_c   14.077
_cell_angle_alpha   89.979
_cell_angle_beta   90.084
_cell_angle_gamma   90.007
_symmetry_Int_Tables_number   1
_cell_volume   522.867
_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
  K  K0  1  0.949  0.051  0.750  1.0
  K  K1  1  0.051  0.949  0.250  1.0
  K  K2  1  0.551  0.551  0.500  1.0
  K  K3  1  0.449  0.449  1.000  1.0
  K  K4  1  0.480  0.022  0.625  1.0
  K  K5  1  0.521  0.978  0.125  1.0
  K  K6  1  0.522  0.020  0.375  1.0
  K  K7  1  0.477  0.980  0.875  1.0
  K  K8  1  0.979  0.520  0.875  1.0
  K  K9  1  0.022  0.480  0.375  1.0
  K  K10  1  0.020  0.522  0.625  1.0
  K  K11  1  0.979  0.479  0.126  1.0
  Ni  Ni12  1  0.504  0.495  0.250  1.0
  Ni  Ni13  1  0.995  0.995  0.000  1.0
  Ni  Ni14  1  0.496  0.505  0.750  1.0
  Ni  Ni15  1  0.004  0.005  0.500  1.0
  O  O16  1  0.701  0.714  0.740  1.0
  O  O17  1  0.298  0.286  0.239  1.0
  O  O18  1  0.214  0.799  0.490  1.0
  O  O19  1  0.786  0.201  0.990  1.0
  O  O20  1  0.286  0.299  0.760  1.0
  O  O21  1  0.714  0.701  0.260  1.0
  O  O22  1  0.799  0.214  0.510  1.0
  O  O23  1  0.202  0.786  0.011  1.0
[/CIF]
.
The crystal structure described by K3NiO2 is Pb(Zr_(1-x)Ti_x)O3-like structured and crystallizes in the monoclinic P2_1 space group. There are six inequivalent K sites. In the first K site, K(1) is bonded in a distorted linear geometry to one O(1) and one O(3) atom. In the second K site, K(2) is bonded in a distorted linear geometry to one O(2) and one O(4) atom. In the third K site, K(3) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing KO4 tetrahedra. In the fourth K site, K(4) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing KO4 tetrahedra. In the fifth K site, K(5) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form a mixture of distorted corner and edge-sharing KO4 tetrahedra. In the sixth K site, K(6) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form a mixture of distorted corner and edge-sharing KO4 tetrahedra. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a linear geometry to one O(2) and one O(4) atom. In the second Ni site, Ni(2) is bonded in a linear geometry to one O(1) and one O(3) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one K(1), one K(5), one K(6), two equivalent K(3), and one Ni(2) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one K(2), one K(5), one K(6), two equivalent K(4), and one Ni(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one K(1), one K(5), one K(6), two equivalent K(3), and one Ni(2) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one K(2), one K(5), one K(6), two equivalent K(4), and one Ni(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K3NiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.094
_cell_length_b   6.095
_cell_length_c   14.077
_cell_angle_alpha   89.979
_cell_angle_beta   90.084
_cell_angle_gamma   90.007
_symmetry_Int_Tables_number   1
_cell_volume   522.867
_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
  K  K0  1  0.949  0.051  0.750  1.0
  K  K1  1  0.051  0.949  0.250  1.0
  K  K2  1  0.551  0.551  0.500  1.0
  K  K3  1  0.449  0.449  1.000  1.0
  K  K4  1  0.480  0.022  0.625  1.0
  K  K5  1  0.521  0.978  0.125  1.0
  K  K6  1  0.522  0.020  0.375  1.0
  K  K7  1  0.477  0.980  0.875  1.0
  K  K8  1  0.979  0.520  0.875  1.0
  K  K9  1  0.022  0.480  0.375  1.0
  K  K10  1  0.020  0.522  0.625  1.0
  K  K11  1  0.979  0.479  0.126  1.0
  Ni  Ni12  1  0.504  0.495  0.250  1.0
  Ni  Ni13  1  0.995  0.995  0.000  1.0
  Ni  Ni14  1  0.496  0.505  0.750  1.0
  Ni  Ni15  1  0.004  0.005  0.500  1.0
  O  O16  1  0.701  0.714  0.740  1.0
  O  O17  1  0.298  0.286  0.239  1.0
  O  O18  1  0.214  0.799  0.490  1.0
  O  O19  1  0.786  0.201  0.990  1.0
  O  O20  1  0.286  0.299  0.760  1.0
  O  O21  1  0.714  0.701  0.260  1.0
  O  O22  1  0.799  0.214  0.510  1.0
  O  O23  1  0.202  0.786  0.011  1.0
[/CIF]
.