The crystal structure described by K2GeSe4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one Se(4), two equivalent Se(1), two equivalent Se(3), and three equivalent Se(2) atoms. In the second K site, K(2) is bonded in a 6-coordinate geometry to three equivalent Se(3) and three equivalent Se(4) atoms. Ge(1) is bonded in a distorted tetrahedral geometry to one Se(1), one Se(2), one Se(3), and one Se(4) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 1-coordinate geometry to two equivalent K(1), one Ge(1), and one Se(2) atom. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to three equivalent K(1), one Ge(1), and one Se(1) atom. In the third Se site, Se(3) is bonded to two equivalent K(1), three equivalent K(2), and one Ge(1) atom to form distorted SeK5Ge octahedra that share corners with two equivalent Se(3)K5Ge octahedra, corners with two equivalent Se(4)K4Ge trigonal bipyramids, edges with three equivalent Se(3)K5Ge octahedra, and edges with five equivalent Se(4)K4Ge trigonal bipyramids. The corner-sharing octahedral tilt angles are 26°. In the fourth Se site, Se(4) is bonded to one K(1), three equivalent K(2), and one Ge(1) atom to form distorted SeK4Ge trigonal bipyramids that share corners with two equivalent Se(3)K5Ge octahedra, corners with four equivalent Se(4)K4Ge trigonal bipyramids, edges with five equivalent Se(3)K5Ge octahedra, and  an edgeedge with one Se(4)K4Ge trigonal bipyramid. The corner-sharing octahedral tilt angles range from 21-56°. is represented by the CIF file [CIF]
data_K2GeSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.336
_cell_length_b   9.013
_cell_length_c   12.024
_cell_angle_alpha   73.806
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   867.606
_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  0.089  0.693  0.156  1.0
  K  K1  1  0.075  0.229  0.453  1.0
  K  K2  1  0.575  0.271  0.547  1.0
  K  K3  1  0.925  0.771  0.547  1.0
  K  K4  1  0.589  0.807  0.844  1.0
  K  K5  1  0.425  0.729  0.453  1.0
  K  K6  1  0.911  0.307  0.844  1.0
  K  K7  1  0.411  0.193  0.156  1.0
  Ge  Ge8  1  0.633  0.548  0.242  1.0
  Ge  Ge9  1  0.133  0.952  0.758  1.0
  Ge  Ge10  1  0.367  0.452  0.758  1.0
  Ge  Ge11  1  0.867  0.048  0.242  1.0
  Se  Se12  1  0.551  0.810  0.138  1.0
  Se  Se13  1  0.286  0.546  0.922  1.0
  Se  Se14  1  0.786  0.954  0.078  1.0
  Se  Se15  1  0.714  0.454  0.078  1.0
  Se  Se16  1  0.123  0.964  0.301  1.0
  Se  Se17  1  0.623  0.536  0.699  1.0
  Se  Se18  1  0.877  0.036  0.699  1.0
  Se  Se19  1  0.377  0.464  0.301  1.0
  Se  Se20  1  0.051  0.690  0.862  1.0
  Se  Se21  1  0.449  0.190  0.862  1.0
  Se  Se22  1  0.949  0.310  0.138  1.0
  Se  Se23  1  0.831  0.537  0.375  1.0
  Se  Se24  1  0.331  0.963  0.625  1.0
  Se  Se25  1  0.169  0.463  0.625  1.0
  Se  Se26  1  0.669  0.037  0.375  1.0
  Se  Se27  1  0.214  0.046  0.922  1.0
[/CIF]
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The crystal structure described by K2GeSe4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one Se(4), two equivalent Se(1), two equivalent Se(3), and three equivalent Se(2) atoms. In the second K site, K(2) is bonded in a 6-coordinate geometry to three equivalent Se(3) and three equivalent Se(4) atoms. Ge(1) is bonded in a distorted tetrahedral geometry to one Se(1), one Se(2), one Se(3), and one Se(4) atom. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 1-coordinate geometry to two equivalent K(1), one Ge(1), and one Se(2) atom. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to three equivalent K(1), one Ge(1), and one Se(1) atom. In the third Se site, Se(3) is bonded to two equivalent K(1), three equivalent K(2), and one Ge(1) atom to form distorted SeK5Ge octahedra that share corners with two equivalent Se(3)K5Ge octahedra, corners with two equivalent Se(4)K4Ge trigonal bipyramids, edges with three equivalent Se(3)K5Ge octahedra, and edges with five equivalent Se(4)K4Ge trigonal bipyramids. The corner-sharing octahedral tilt angles are 26°. In the fourth Se site, Se(4) is bonded to one K(1), three equivalent K(2), and one Ge(1) atom to form distorted SeK4Ge trigonal bipyramids that share corners with two equivalent Se(3)K5Ge octahedra, corners with four equivalent Se(4)K4Ge trigonal bipyramids, edges with five equivalent Se(3)K5Ge octahedra, and  an edgeedge with one Se(4)K4Ge trigonal bipyramid. The corner-sharing octahedral tilt angles range from 21-56°. is represented by the CIF file [CIF]
data_K2GeSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.336
_cell_length_b   9.013
_cell_length_c   12.024
_cell_angle_alpha   73.806
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   867.606
_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  0.089  0.693  0.156  1.0
  K  K1  1  0.075  0.229  0.453  1.0
  K  K2  1  0.575  0.271  0.547  1.0
  K  K3  1  0.925  0.771  0.547  1.0
  K  K4  1  0.589  0.807  0.844  1.0
  K  K5  1  0.425  0.729  0.453  1.0
  K  K6  1  0.911  0.307  0.844  1.0
  K  K7  1  0.411  0.193  0.156  1.0
  Ge  Ge8  1  0.633  0.548  0.242  1.0
  Ge  Ge9  1  0.133  0.952  0.758  1.0
  Ge  Ge10  1  0.367  0.452  0.758  1.0
  Ge  Ge11  1  0.867  0.048  0.242  1.0
  Se  Se12  1  0.551  0.810  0.138  1.0
  Se  Se13  1  0.286  0.546  0.922  1.0
  Se  Se14  1  0.786  0.954  0.078  1.0
  Se  Se15  1  0.714  0.454  0.078  1.0
  Se  Se16  1  0.123  0.964  0.301  1.0
  Se  Se17  1  0.623  0.536  0.699  1.0
  Se  Se18  1  0.877  0.036  0.699  1.0
  Se  Se19  1  0.377  0.464  0.301  1.0
  Se  Se20  1  0.051  0.690  0.862  1.0
  Se  Se21  1  0.449  0.190  0.862  1.0
  Se  Se22  1  0.949  0.310  0.138  1.0
  Se  Se23  1  0.831  0.537  0.375  1.0
  Se  Se24  1  0.331  0.963  0.625  1.0
  Se  Se25  1  0.169  0.463  0.625  1.0
  Se  Se26  1  0.669  0.037  0.375  1.0
  Se  Se27  1  0.214  0.046  0.922  1.0
[/CIF]
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