The structure described by K2CuF4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mcm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to one F(1), four equivalent F(3), and four equivalent F(4) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to one F(3), four equivalent F(1), and four equivalent F(2) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent F(3) and four equivalent F(4) atoms to form corner-sharing CuF6 octahedra. The corner-sharing octahedra are not tilted. In the second Cu site, Cu(2) is bonded to two equivalent F(1) and four equivalent F(2) atoms to form corner-sharing CuF6 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent F sites. In the first F site, F(1) is bonded to one K(1), four equivalent K(2), and one Cu(2) atom to form distorted FK5Cu octahedra that share corners with four equivalent F(4)K4Cu2 octahedra, corners with five equivalent F(1)K5Cu octahedra, corners with eight equivalent F(2)K4Cu2 octahedra, edges with four equivalent F(1)K5Cu octahedra, edges with four equivalent F(3)K5Cu octahedra, and faces with four equivalent F(2)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the second F site, F(2) is bonded to four equivalent K(2) and two equivalent Cu(2) atoms to form FK4Cu2 octahedra that share corners with two equivalent F(2)K4Cu2 octahedra, corners with four equivalent F(3)K5Cu octahedra, corners with eight equivalent F(1)K5Cu octahedra, edges with two equivalent F(2)K4Cu2 octahedra, faces with four equivalent F(2)K4Cu2 octahedra, and faces with four equivalent F(1)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the third F site, F(3) is bonded to one K(2), four equivalent K(1), and one Cu(1) atom to form distorted FK5Cu octahedra that share corners with four equivalent F(2)K4Cu2 octahedra, corners with five equivalent F(3)K5Cu octahedra, corners with eight equivalent F(4)K4Cu2 octahedra, edges with four equivalent F(1)K5Cu octahedra, edges with four equivalent F(3)K5Cu octahedra, and faces with four equivalent F(4)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-58°. In the fourth F site, F(4) is bonded to four equivalent K(1) and two equivalent Cu(1) atoms to form distorted FK4Cu2 octahedra that share corners with two equivalent F(4)K4Cu2 octahedra, corners with four equivalent F(1)K5Cu octahedra, corners with eight equivalent F(3)K5Cu octahedra, edges with two equivalent F(4)K4Cu2 octahedra, faces with four equivalent F(4)K4Cu2 octahedra, and faces with four equivalent F(3)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 0-58°. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2CuF4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.801
_cell_length_b   5.801
_cell_length_c   13.292
_cell_angle_alpha   102.598
_cell_angle_beta   102.598
_cell_angle_gamma   90.006
_symmetry_Int_Tables_number   1
_cell_volume   425.544
_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  0.429  0.429  0.858  1.0
  K  K1  1  0.571  0.571  0.142  1.0
  K  K2  1  0.929  0.929  0.858  1.0
  K  K3  1  0.071  0.071  0.142  1.0
  K  K4  1  0.820  0.320  0.641  1.0
  K  K5  1  0.180  0.680  0.359  1.0
  K  K6  1  0.680  0.180  0.359  1.0
  K  K7  1  0.320  0.820  0.641  1.0
  Cu  Cu8  1  0.000  0.500  0.000  1.0
  Cu  Cu9  1  0.500  0.000  0.000  1.0
  Cu  Cu10  1  0.750  0.750  0.500  1.0
  Cu  Cu11  1  0.250  0.250  0.500  1.0
  F  F12  1  0.174  0.174  0.349  1.0
  F  F13  1  0.500  0.000  0.500  1.0
  F  F14  1  0.577  0.077  0.154  1.0
  F  F15  1  0.500  0.500  0.500  1.0
  F  F16  1  0.732  0.768  0.000  1.0
  F  F17  1  0.826  0.826  0.651  1.0
  F  F18  1  0.077  0.577  0.154  1.0
  F  F19  1  0.423  0.923  0.846  1.0
  F  F20  1  0.326  0.326  0.651  1.0
  F  F21  1  0.000  0.000  0.500  1.0
  F  F22  1  0.268  0.232  1.000  1.0
  F  F23  1  0.923  0.423  0.846  1.0
  F  F24  1  0.232  0.732  0.000  1.0
  F  F25  1  0.674  0.674  0.349  1.0
  F  F26  1  0.768  0.268  1.000  1.0
  F  F27  1  0.000  0.500  0.500  1.0
[/CIF]
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The structure described by K2CuF4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mcm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to one F(1), four equivalent F(3), and four equivalent F(4) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to one F(3), four equivalent F(1), and four equivalent F(2) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent F(3) and four equivalent F(4) atoms to form corner-sharing CuF6 octahedra. The corner-sharing octahedra are not tilted. In the second Cu site, Cu(2) is bonded to two equivalent F(1) and four equivalent F(2) atoms to form corner-sharing CuF6 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent F sites. In the first F site, F(1) is bonded to one K(1), four equivalent K(2), and one Cu(2) atom to form distorted FK5Cu octahedra that share corners with four equivalent F(4)K4Cu2 octahedra, corners with five equivalent F(1)K5Cu octahedra, corners with eight equivalent F(2)K4Cu2 octahedra, edges with four equivalent F(1)K5Cu octahedra, edges with four equivalent F(3)K5Cu octahedra, and faces with four equivalent F(2)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the second F site, F(2) is bonded to four equivalent K(2) and two equivalent Cu(2) atoms to form FK4Cu2 octahedra that share corners with two equivalent F(2)K4Cu2 octahedra, corners with four equivalent F(3)K5Cu octahedra, corners with eight equivalent F(1)K5Cu octahedra, edges with two equivalent F(2)K4Cu2 octahedra, faces with four equivalent F(2)K4Cu2 octahedra, and faces with four equivalent F(1)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the third F site, F(3) is bonded to one K(2), four equivalent K(1), and one Cu(1) atom to form distorted FK5Cu octahedra that share corners with four equivalent F(2)K4Cu2 octahedra, corners with five equivalent F(3)K5Cu octahedra, corners with eight equivalent F(4)K4Cu2 octahedra, edges with four equivalent F(1)K5Cu octahedra, edges with four equivalent F(3)K5Cu octahedra, and faces with four equivalent F(4)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-58°. In the fourth F site, F(4) is bonded to four equivalent K(1) and two equivalent Cu(1) atoms to form distorted FK4Cu2 octahedra that share corners with two equivalent F(4)K4Cu2 octahedra, corners with four equivalent F(1)K5Cu octahedra, corners with eight equivalent F(3)K5Cu octahedra, edges with two equivalent F(4)K4Cu2 octahedra, faces with four equivalent F(4)K4Cu2 octahedra, and faces with four equivalent F(3)K5Cu octahedra. The corner-sharing octahedral tilt angles range from 0-58°. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2CuF4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.801
_cell_length_b   5.801
_cell_length_c   13.292
_cell_angle_alpha   102.598
_cell_angle_beta   102.598
_cell_angle_gamma   90.006
_symmetry_Int_Tables_number   1
_cell_volume   425.544
_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  0.429  0.429  0.858  1.0
  K  K1  1  0.571  0.571  0.142  1.0
  K  K2  1  0.929  0.929  0.858  1.0
  K  K3  1  0.071  0.071  0.142  1.0
  K  K4  1  0.820  0.320  0.641  1.0
  K  K5  1  0.180  0.680  0.359  1.0
  K  K6  1  0.680  0.180  0.359  1.0
  K  K7  1  0.320  0.820  0.641  1.0
  Cu  Cu8  1  0.000  0.500  0.000  1.0
  Cu  Cu9  1  0.500  0.000  0.000  1.0
  Cu  Cu10  1  0.750  0.750  0.500  1.0
  Cu  Cu11  1  0.250  0.250  0.500  1.0
  F  F12  1  0.174  0.174  0.349  1.0
  F  F13  1  0.500  0.000  0.500  1.0
  F  F14  1  0.577  0.077  0.154  1.0
  F  F15  1  0.500  0.500  0.500  1.0
  F  F16  1  0.732  0.768  0.000  1.0
  F  F17  1  0.826  0.826  0.651  1.0
  F  F18  1  0.077  0.577  0.154  1.0
  F  F19  1  0.423  0.923  0.846  1.0
  F  F20  1  0.326  0.326  0.651  1.0
  F  F21  1  0.000  0.000  0.500  1.0
  F  F22  1  0.268  0.232  1.000  1.0
  F  F23  1  0.923  0.423  0.846  1.0
  F  F24  1  0.232  0.732  0.000  1.0
  F  F25  1  0.674  0.674  0.349  1.0
  F  F26  1  0.768  0.268  1.000  1.0
  F  F27  1  0.000  0.500  0.500  1.0
[/CIF]
.