The material described by K2Dy4Cu4Se9 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 Dy sites. In the first Dy site, Dy(1) is bonded to one Se(3), two equivalent Se(2), and three equivalent Se(1) atoms to form DySe6 octahedra that share  a cornercorner with one Dy(2)Se6 octahedra, corners with four equivalent Cu(1)Se4 tetrahedra, edges with four equivalent Dy(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 Dy site, Dy(2) is bonded to one Se(3), two equivalent Se(5), and three equivalent Se(4) atoms to form DySe6 octahedra that share  a cornercorner with one Dy(1)Se6 octahedra, corners with two equivalent Dy(2)Se6 octahedra,  a cornercorner with one Cu(2)Se4 tetrahedra, edges with five equivalent Dy(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 Dy(1)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with three equivalent Dy(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 Dy(2)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with two equivalent Dy(1)Se6 octahedra, and edges with two equivalent Dy(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 Dy(1), and two equivalent Cu(1) atoms to form distorted SeKDy3Cu2 octahedra that share corners with two equivalent Se(4)K2Dy3Cu octahedra and edges with four equivalent Se(1)KDy3Cu2 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 Dy(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 Dy(1), one Dy(2), and two equivalent Cu(2) atoms. In the fourth Se site, Se(4) is bonded to two equivalent K(1), three equivalent Dy(2), and one Cu(2) atom to form distorted SeK2Dy3Cu octahedra that share corners with two equivalent Se(1)KDy3Cu2 octahedra and edges with four equivalent Se(4)K2Dy3Cu 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 Dy(2) atoms. is represented by the CIF file [CIF]
data_K2Dy4Cu4Se9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.455
_cell_length_b   7.455
_cell_length_c   16.520
_cell_angle_alpha   71.410
_cell_angle_beta   71.410
_cell_angle_gamma   32.040
_symmetry_Int_Tables_number   1
_cell_volume   459.529
_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
  Dy  Dy2  1  0.232  0.232  0.897  1.0
  Dy  Dy3  1  0.345  0.345  0.556  1.0
  Dy  Dy4  1  0.655  0.655  0.444  1.0
  Dy  Dy5  1  0.768  0.768  0.103  1.0
  Cu  Cu6  1  0.424  0.424  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  0.576  0.576  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  0.699  0.699  0.604  1.0
  Se  Se14  1  0.000  0.000  0.500  1.0
  Se  Se15  1  0.301  0.301  0.396  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 described by K2Dy4Cu4Se9 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 Dy sites. In the first Dy site, Dy(1) is bonded to one Se(3), two equivalent Se(2), and three equivalent Se(1) atoms to form DySe6 octahedra that share  a cornercorner with one Dy(2)Se6 octahedra, corners with four equivalent Cu(1)Se4 tetrahedra, edges with four equivalent Dy(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 Dy site, Dy(2) is bonded to one Se(3), two equivalent Se(5), and three equivalent Se(4) atoms to form DySe6 octahedra that share  a cornercorner with one Dy(1)Se6 octahedra, corners with two equivalent Dy(2)Se6 octahedra,  a cornercorner with one Cu(2)Se4 tetrahedra, edges with five equivalent Dy(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 Dy(1)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with three equivalent Dy(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 Dy(2)Se6 octahedra, corners with two equivalent Cu(1)Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with two equivalent Dy(1)Se6 octahedra, and edges with two equivalent Dy(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 Dy(1), and two equivalent Cu(1) atoms to form distorted SeKDy3Cu2 octahedra that share corners with two equivalent Se(4)K2Dy3Cu octahedra and edges with four equivalent Se(1)KDy3Cu2 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 Dy(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 Dy(1), one Dy(2), and two equivalent Cu(2) atoms. In the fourth Se site, Se(4) is bonded to two equivalent K(1), three equivalent Dy(2), and one Cu(2) atom to form distorted SeK2Dy3Cu octahedra that share corners with two equivalent Se(1)KDy3Cu2 octahedra and edges with four equivalent Se(4)K2Dy3Cu 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 Dy(2) atoms. is represented by the CIF file [CIF]
data_K2Dy4Cu4Se9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.455
_cell_length_b   7.455
_cell_length_c   16.520
_cell_angle_alpha   71.410
_cell_angle_beta   71.410
_cell_angle_gamma   32.040
_symmetry_Int_Tables_number   1
_cell_volume   459.529
_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
  Dy  Dy2  1  0.232  0.232  0.897  1.0
  Dy  Dy3  1  0.345  0.345  0.556  1.0
  Dy  Dy4  1  0.655  0.655  0.444  1.0
  Dy  Dy5  1  0.768  0.768  0.103  1.0
  Cu  Cu6  1  0.424  0.424  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  0.576  0.576  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  0.699  0.699  0.604  1.0
  Se  Se14  1  0.000  0.000  0.500  1.0
  Se  Se15  1  0.301  0.301  0.396  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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