The crystal structure described by K2NiF4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. K(1) is bonded in a 9-coordinate geometry to four equivalent F(1) and five equivalent F(2) atoms. Ni(1) is bonded to two equivalent F(2) and four equivalent F(1) atoms to form corner-sharing NiF6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent F sites. In the first F site, F(2) is bonded to five equivalent K(1) and one Ni(1) atom to form distorted FK5Ni octahedra that share corners with five equivalent F(2)K5Ni octahedra, corners with twelve equivalent F(1)K4Ni2 octahedra, edges with eight equivalent F(2)K5Ni octahedra, and faces with four equivalent F(1)K4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-57°. In the second F site, F(1) is bonded to four equivalent K(1) and two equivalent Ni(1) atoms to form distorted FK4Ni2 octahedra that share corners with two equivalent F(1)K4Ni2 octahedra, corners with twelve equivalent F(2)K5Ni octahedra, edges with two equivalent F(1)K4Ni2 octahedra, faces with four equivalent F(1)K4Ni2 octahedra, and faces with four equivalent F(2)K5Ni octahedra. The corner-sharing octahedral tilt angles range from 0-57°. is represented by the CIF card [CIF]
data_K2NiF4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.089
_cell_length_b   7.089
_cell_length_c   7.089
_cell_angle_alpha   147.208
_cell_angle_beta   147.208
_cell_angle_gamma   47.055
_symmetry_Int_Tables_number   1
_cell_volume   104.108
_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
  K  K0  1  0.355  0.355  0.000  1.0
  K  K1  1  0.645  0.645  0.000  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  F  F3  1  0.000  0.500  0.500  1.0
  F  F4  1  0.500  0.000  0.500  1.0
  F  F5  1  0.154  0.154  0.000  1.0
  F  F6  1  0.846  0.846  0.000  1.0
[/CIF]
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The crystal structure described by K2NiF4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. K(1) is bonded in a 9-coordinate geometry to four equivalent F(1) and five equivalent F(2) atoms. Ni(1) is bonded to two equivalent F(2) and four equivalent F(1) atoms to form corner-sharing NiF6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent F sites. In the first F site, F(2) is bonded to five equivalent K(1) and one Ni(1) atom to form distorted FK5Ni octahedra that share corners with five equivalent F(2)K5Ni octahedra, corners with twelve equivalent F(1)K4Ni2 octahedra, edges with eight equivalent F(2)K5Ni octahedra, and faces with four equivalent F(1)K4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-57°. In the second F site, F(1) is bonded to four equivalent K(1) and two equivalent Ni(1) atoms to form distorted FK4Ni2 octahedra that share corners with two equivalent F(1)K4Ni2 octahedra, corners with twelve equivalent F(2)K5Ni octahedra, edges with two equivalent F(1)K4Ni2 octahedra, faces with four equivalent F(1)K4Ni2 octahedra, and faces with four equivalent F(2)K5Ni octahedra. The corner-sharing octahedral tilt angles range from 0-57°. is represented by the CIF card [CIF]
data_K2NiF4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.089
_cell_length_b   7.089
_cell_length_c   7.089
_cell_angle_alpha   147.208
_cell_angle_beta   147.208
_cell_angle_gamma   47.055
_symmetry_Int_Tables_number   1
_cell_volume   104.108
_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
  K  K0  1  0.355  0.355  0.000  1.0
  K  K1  1  0.645  0.645  0.000  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  F  F3  1  0.000  0.500  0.500  1.0
  F  F4  1  0.500  0.000  0.500  1.0
  F  F5  1  0.154  0.154  0.000  1.0
  F  F6  1  0.846  0.846  0.000  1.0
[/CIF]
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