The material structure described by K2Y4Cu4Se9 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 7-coordinate geometry to one Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one Se(3), two equivalent Se(2), and three equivalent Se(1) atoms to form YSe6 octahedra that share  a cornercorner with one Y(2)Se6 octahedra, corners with four equivalent Cu(1)Se4 tetrahedra, edges with four equivalent Y(1)Se6 octahedra, edges with two equivalent Cu(2)Se4 tetrahedra, and edges with three equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. In the second Y site, Y(2) is bonded to one Se(3), two equivalent Se(5), and three equivalent Se(4) atoms to form YSe6 octahedra that share  a cornercorner with one Y(1)Se6 octahedra, corners with two equivalent Y(2)Se6 octahedra,  a cornercorner with one Cu(2)Se4 tetrahedra, edges with five equivalent Y(2)Se6 octahedra, and edges with two equivalent Cu(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 0-39°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent Y(1)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with three equivalent Y(1)Se6 octahedra, and  an edgeedge with one Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 19-63°. In the second Cu site, Cu(2) is bonded to one Se(2), one Se(4), and two equivalent Se(3) atoms to form CuSe4 tetrahedra that share  a cornercorner with one Y(2)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with two equivalent Y(1)Se6 octahedra, and edges with two equivalent Y(2)Se6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are five inequivalent Se sites. In the first Se site, Se(1) is bonded to one K(1), three equivalent Y(1), and two equivalent Cu(1) atoms to form distorted SeKY3Cu2 octahedra that share corners with two equivalent Se(4)K2Y3Cu octahedra and edges with four equivalent Se(1)KY3Cu2 octahedra. The corner-sharing octahedral tilt angles are 41°. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent K(1), two equivalent Y(1), one Cu(2), and two equivalent Cu(1) atoms. In the third Se site, Se(3) is bonded in a 6-coordinate geometry to two equivalent K(1), one Y(1), one Y(2), and two equivalent Cu(2) atoms. In the fourth Se site, Se(4) is bonded to two equivalent K(1), three equivalent Y(2), and one Cu(2) atom to form distorted SeK2Y3Cu octahedra that share corners with two equivalent Se(1)KY3Cu2 octahedra and edges with four equivalent Se(4)K2Y3Cu octahedra. The corner-sharing octahedral tilt angles are 41°. In the fifth Se site, Se(5) is bonded in a square co-planar geometry to four equivalent Y(2) atoms. is represented by the CIF file [CIF]
data_K2Y4Cu4Se9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.469
_cell_length_b   7.469
_cell_length_c   16.556
_cell_angle_alpha   71.387
_cell_angle_beta   71.387
_cell_angle_gamma   32.044
_symmetry_Int_Tables_number   1
_cell_volume   462.267
_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  0.033  0.033  0.731  1.0
  K  K1  1  0.967  0.967  0.269  1.0
  Y  Y2  1  0.232  0.232  0.897  1.0
  Y  Y3  1  0.345  0.345  0.556  1.0
  Y  Y4  1  0.655  0.655  0.444  1.0
  Y  Y5  1  0.768  0.768  0.103  1.0
  Cu  Cu6  1  0.425  0.425  0.971  1.0
  Cu  Cu7  1  0.760  0.760  0.729  1.0
  Cu  Cu8  1  0.240  0.240  0.271  1.0
  Cu  Cu9  1  0.575  0.575  0.029  1.0
  Se  Se10  1  0.865  0.865  0.922  1.0
  Se  Se11  1  0.607  0.607  0.870  1.0
  Se  Se12  1  0.356  0.356  0.723  1.0
  Se  Se13  1  0.698  0.698  0.605  1.0
  Se  Se14  1  0.000  0.000  0.500  1.0
  Se  Se15  1  0.302  0.302  0.395  1.0
  Se  Se16  1  0.644  0.644  0.277  1.0
  Se  Se17  1  0.393  0.393  0.130  1.0
  Se  Se18  1  0.135  0.135  0.078  1.0
[/CIF]
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The material structure described by K2Y4Cu4Se9 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 7-coordinate geometry to one Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one Se(3), two equivalent Se(2), and three equivalent Se(1) atoms to form YSe6 octahedra that share  a cornercorner with one Y(2)Se6 octahedra, corners with four equivalent Cu(1)Se4 tetrahedra, edges with four equivalent Y(1)Se6 octahedra, edges with two equivalent Cu(2)Se4 tetrahedra, and edges with three equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. In the second Y site, Y(2) is bonded to one Se(3), two equivalent Se(5), and three equivalent Se(4) atoms to form YSe6 octahedra that share  a cornercorner with one Y(1)Se6 octahedra, corners with two equivalent Y(2)Se6 octahedra,  a cornercorner with one Cu(2)Se4 tetrahedra, edges with five equivalent Y(2)Se6 octahedra, and edges with two equivalent Cu(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 0-39°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent Y(1)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with three equivalent Y(1)Se6 octahedra, and  an edgeedge with one Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 19-63°. In the second Cu site, Cu(2) is bonded to one Se(2), one Se(4), and two equivalent Se(3) atoms to form CuSe4 tetrahedra that share  a cornercorner with one Y(2)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with two equivalent Y(1)Se6 octahedra, and edges with two equivalent Y(2)Se6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are five inequivalent Se sites. In the first Se site, Se(1) is bonded to one K(1), three equivalent Y(1), and two equivalent Cu(1) atoms to form distorted SeKY3Cu2 octahedra that share corners with two equivalent Se(4)K2Y3Cu octahedra and edges with four equivalent Se(1)KY3Cu2 octahedra. The corner-sharing octahedral tilt angles are 41°. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent K(1), two equivalent Y(1), one Cu(2), and two equivalent Cu(1) atoms. In the third Se site, Se(3) is bonded in a 6-coordinate geometry to two equivalent K(1), one Y(1), one Y(2), and two equivalent Cu(2) atoms. In the fourth Se site, Se(4) is bonded to two equivalent K(1), three equivalent Y(2), and one Cu(2) atom to form distorted SeK2Y3Cu octahedra that share corners with two equivalent Se(1)KY3Cu2 octahedra and edges with four equivalent Se(4)K2Y3Cu octahedra. The corner-sharing octahedral tilt angles are 41°. In the fifth Se site, Se(5) is bonded in a square co-planar geometry to four equivalent Y(2) atoms. is represented by the CIF file [CIF]
data_K2Y4Cu4Se9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.469
_cell_length_b   7.469
_cell_length_c   16.556
_cell_angle_alpha   71.387
_cell_angle_beta   71.387
_cell_angle_gamma   32.044
_symmetry_Int_Tables_number   1
_cell_volume   462.267
_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  0.033  0.033  0.731  1.0
  K  K1  1  0.967  0.967  0.269  1.0
  Y  Y2  1  0.232  0.232  0.897  1.0
  Y  Y3  1  0.345  0.345  0.556  1.0
  Y  Y4  1  0.655  0.655  0.444  1.0
  Y  Y5  1  0.768  0.768  0.103  1.0
  Cu  Cu6  1  0.425  0.425  0.971  1.0
  Cu  Cu7  1  0.760  0.760  0.729  1.0
  Cu  Cu8  1  0.240  0.240  0.271  1.0
  Cu  Cu9  1  0.575  0.575  0.029  1.0
  Se  Se10  1  0.865  0.865  0.922  1.0
  Se  Se11  1  0.607  0.607  0.870  1.0
  Se  Se12  1  0.356  0.356  0.723  1.0
  Se  Se13  1  0.698  0.698  0.605  1.0
  Se  Se14  1  0.000  0.000  0.500  1.0
  Se  Se15  1  0.302  0.302  0.395  1.0
  Se  Se16  1  0.644  0.644  0.277  1.0
  Se  Se17  1  0.393  0.393  0.130  1.0
  Se  Se18  1  0.135  0.135  0.078  1.0
[/CIF]
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