The material described by K3(FeO2)2 crystallizes in the orthorhombic Fddd space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(2) atoms. In the second K site, K(2) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. Fe(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form corner-sharing FeO4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent K(1), two equivalent K(2), and two equivalent Fe(1) atoms to form a mixture of corner and edge-sharing OK4Fe2 octahedra. The corner-sharing octahedral tilt angles range from 12-65°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent K(1) and two equivalent Fe(1) atoms. is represented by the CIF file [CIF]
data_K3(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.351
_cell_length_b   9.104
_cell_length_c   6.536
_cell_angle_alpha   81.077
_cell_angle_beta   60.331
_cell_angle_gamma   38.592
_symmetry_Int_Tables_number   1
_cell_volume   301.731
_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
  K  K0  1  0.609  0.609  0.391  1.0
  K  K1  1  0.250  0.250  0.250  1.0
  K  K2  1  0.641  0.641  0.859  1.0
  K  K3  1  0.859  0.859  0.641  1.0
  K  K4  1  0.000  0.000  0.000  1.0
  K  K5  1  0.391  0.391  0.609  1.0
  Fe  Fe6  1  0.058  0.058  0.442  1.0
  Fe  Fe7  1  0.808  0.808  0.192  1.0
  Fe  Fe8  1  0.192  0.192  0.808  1.0
  Fe  Fe9  1  0.442  0.442  0.058  1.0
  O  O10  1  0.125  0.625  0.125  1.0
  O  O11  1  0.682  0.318  0.682  1.0
  O  O12  1  0.932  0.568  0.932  1.0
  O  O13  1  0.568  0.932  0.568  1.0
  O  O14  1  0.318  0.682  0.318  1.0
  O  O15  1  0.625  0.125  0.125  1.0
  O  O16  1  0.125  0.125  0.625  1.0
  O  O17  1  0.125  0.125  0.125  1.0
[/CIF]
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The material described by K3(FeO2)2 crystallizes in the orthorhombic Fddd space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(2) atoms. In the second K site, K(2) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. Fe(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form corner-sharing FeO4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent K(1), two equivalent K(2), and two equivalent Fe(1) atoms to form a mixture of corner and edge-sharing OK4Fe2 octahedra. The corner-sharing octahedral tilt angles range from 12-65°. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent K(1) and two equivalent Fe(1) atoms. is represented by the CIF file [CIF]
data_K3(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.351
_cell_length_b   9.104
_cell_length_c   6.536
_cell_angle_alpha   81.077
_cell_angle_beta   60.331
_cell_angle_gamma   38.592
_symmetry_Int_Tables_number   1
_cell_volume   301.731
_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
  K  K0  1  0.609  0.609  0.391  1.0
  K  K1  1  0.250  0.250  0.250  1.0
  K  K2  1  0.641  0.641  0.859  1.0
  K  K3  1  0.859  0.859  0.641  1.0
  K  K4  1  0.000  0.000  0.000  1.0
  K  K5  1  0.391  0.391  0.609  1.0
  Fe  Fe6  1  0.058  0.058  0.442  1.0
  Fe  Fe7  1  0.808  0.808  0.192  1.0
  Fe  Fe8  1  0.192  0.192  0.808  1.0
  Fe  Fe9  1  0.442  0.442  0.058  1.0
  O  O10  1  0.125  0.625  0.125  1.0
  O  O11  1  0.682  0.318  0.682  1.0
  O  O12  1  0.932  0.568  0.932  1.0
  O  O13  1  0.568  0.932  0.568  1.0
  O  O14  1  0.318  0.682  0.318  1.0
  O  O15  1  0.625  0.125  0.125  1.0
  O  O16  1  0.125  0.125  0.625  1.0
  O  O17  1  0.125  0.125  0.125  1.0
[/CIF]
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