The compound described by K3(FeSe)8 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a distorted body-centered cubic geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. In the second K site, K(2) is bonded in a body-centered cubic geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. In the second Fe site, Fe(2) is bonded in a 4-coordinate geometry to one Se(1), one Se(4), and two equivalent Se(2) atoms. In the third Fe site, Fe(3) is bonded to one Se(2), one Se(4), and two equivalent Se(3) atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. In the fourth Fe site, Fe(4) is bonded to one Se(1), one Se(3), and two equivalent Se(4) atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 7-coordinate geometry to one K(2), two equivalent K(1), one Fe(2), one Fe(4), and two equivalent Fe(1) atoms. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to one K(2), two equivalent K(1), one Fe(1), one Fe(3), and two equivalent Fe(2) atoms. In the third Se site, Se(3) is bonded in a 7-coordinate geometry to one K(2), two equivalent K(1), one Fe(1), one Fe(4), and two equivalent Fe(3) atoms. In the fourth Se site, Se(4) is bonded in a 7-coordinate geometry to one K(2), two equivalent K(1), one Fe(2), one Fe(3), and two equivalent Fe(4) atoms. is represented by the CIF file [CIF]
data_K3(FeSe)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.451
_cell_length_b   8.090
_cell_length_c   8.212
_cell_angle_alpha   71.976
_cell_angle_beta   63.065
_cell_angle_gamma   76.653
_symmetry_Int_Tables_number   1
_cell_volume   417.216
_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  0.763  0.000  0.474  1.0
  K  K1  1  0.500  0.000  0.000  1.0
  K  K2  1  0.237  1.000  0.526  1.0
  Fe  Fe3  1  0.063  0.499  0.625  1.0
  Fe  Fe4  1  0.563  0.500  0.624  1.0
  Fe  Fe5  1  0.812  0.499  0.125  1.0
  Fe  Fe6  1  0.313  0.500  0.125  1.0
  Fe  Fe7  1  0.937  0.501  0.375  1.0
  Fe  Fe8  1  0.437  0.500  0.376  1.0
  Fe  Fe9  1  0.687  0.500  0.875  1.0
  Fe  Fe10  1  0.188  0.501  0.875  1.0
  Se  Se11  1  0.162  0.715  0.320  1.0
  Se  Se12  1  0.661  0.714  0.320  1.0
  Se  Se13  1  0.910  0.713  0.820  1.0
  Se  Se14  1  0.412  0.714  0.820  1.0
  Se  Se15  1  0.838  0.285  0.680  1.0
  Se  Se16  1  0.339  0.286  0.680  1.0
  Se  Se17  1  0.588  0.286  0.180  1.0
  Se  Se18  1  0.090  0.287  0.180  1.0
[/CIF]
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The compound described by K3(FeSe)8 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a distorted body-centered cubic geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. In the second K site, K(2) is bonded in a body-centered cubic geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. In the second Fe site, Fe(2) is bonded in a 4-coordinate geometry to one Se(1), one Se(4), and two equivalent Se(2) atoms. In the third Fe site, Fe(3) is bonded to one Se(2), one Se(4), and two equivalent Se(3) atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. In the fourth Fe site, Fe(4) is bonded to one Se(1), one Se(3), and two equivalent Se(4) atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 7-coordinate geometry to one K(2), two equivalent K(1), one Fe(2), one Fe(4), and two equivalent Fe(1) atoms. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to one K(2), two equivalent K(1), one Fe(1), one Fe(3), and two equivalent Fe(2) atoms. In the third Se site, Se(3) is bonded in a 7-coordinate geometry to one K(2), two equivalent K(1), one Fe(1), one Fe(4), and two equivalent Fe(3) atoms. In the fourth Se site, Se(4) is bonded in a 7-coordinate geometry to one K(2), two equivalent K(1), one Fe(2), one Fe(3), and two equivalent Fe(4) atoms. is represented by the CIF file [CIF]
data_K3(FeSe)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.451
_cell_length_b   8.090
_cell_length_c   8.212
_cell_angle_alpha   71.976
_cell_angle_beta   63.065
_cell_angle_gamma   76.653
_symmetry_Int_Tables_number   1
_cell_volume   417.216
_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  0.763  0.000  0.474  1.0
  K  K1  1  0.500  0.000  0.000  1.0
  K  K2  1  0.237  1.000  0.526  1.0
  Fe  Fe3  1  0.063  0.499  0.625  1.0
  Fe  Fe4  1  0.563  0.500  0.624  1.0
  Fe  Fe5  1  0.812  0.499  0.125  1.0
  Fe  Fe6  1  0.313  0.500  0.125  1.0
  Fe  Fe7  1  0.937  0.501  0.375  1.0
  Fe  Fe8  1  0.437  0.500  0.376  1.0
  Fe  Fe9  1  0.687  0.500  0.875  1.0
  Fe  Fe10  1  0.188  0.501  0.875  1.0
  Se  Se11  1  0.162  0.715  0.320  1.0
  Se  Se12  1  0.661  0.714  0.320  1.0
  Se  Se13  1  0.910  0.713  0.820  1.0
  Se  Se14  1  0.412  0.714  0.820  1.0
  Se  Se15  1  0.838  0.285  0.680  1.0
  Se  Se16  1  0.339  0.286  0.680  1.0
  Se  Se17  1  0.588  0.286  0.180  1.0
  Se  Se18  1  0.090  0.287  0.180  1.0
[/CIF]
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