The structure described by CsEr2Cu3Se5 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 10-coordinate geometry to two equivalent Cu(1), two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms. Er(1) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(3) atoms to form ErSe6 octahedra that share  a cornercorner with one Er(1)Se6 octahedra, corners with four equivalent Cu(2)Se4 tetrahedra, edges with four equivalent Er(1)Se6 octahedra, edges with two equivalent Cu(1)Cs2Se4 tetrahedra, and edges with three equivalent Cu(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Cs(1), two equivalent Se(1), and two equivalent Se(2) atoms to form distorted CuCs2Se4 tetrahedra that share corners with four equivalent Se(3)CsEr3Cu2 octahedra, corners with four equivalent Cu(2)Se4 tetrahedra, edges with four equivalent Er(1)Se6 octahedra, and edges with two equivalent Cu(1)Cs2Se4 tetrahedra. The corner-sharing octahedral tilt angles are 67°. In the second Cu site, Cu(2) is bonded to two equivalent Se(2) and two equivalent Se(3) atoms to form CuSe4 tetrahedra that share corners with four equivalent Er(1)Se6 octahedra, corners with two equivalent Cu(1)Cs2Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with three equivalent Er(1)Se6 octahedra, and  an edgeedge with one Cu(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 15-60°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Er(1), and two equivalent Cu(1) atoms. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent Cs(1), two equivalent Er(1), one Cu(1), and two equivalent Cu(2) atoms. In the third Se site, Se(3) is bonded to one Cs(1), three equivalent Er(1), and two equivalent Cu(2) atoms to form distorted SeCsEr3Cu2 octahedra that share  a cornercorner with one Se(3)CsEr3Cu2 octahedra, corners with two equivalent Cu(1)Cs2Se4 tetrahedra, and edges with four equivalent Se(3)CsEr3Cu2 octahedra. The corner-sharing octahedral tilt angles are 54°. is represented by the CIF card [CIF]
data_CsEr2Cu3Se5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.634
_cell_length_b   7.634
_cell_length_c   17.273
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   148.701
_symmetry_Int_Tables_number   1
_cell_volume   522.895
_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
  Cs  Cs0  1  0.061  0.939  0.750  1.0
  Cs  Cs1  1  0.939  0.061  0.250  1.0
  Er  Er2  1  0.808  0.192  0.591  1.0
  Er  Er3  1  0.192  0.808  0.409  1.0
  Er  Er4  1  0.192  0.808  0.091  1.0
  Er  Er5  1  0.808  0.192  0.909  1.0
  Cu  Cu6  1  0.344  0.656  0.750  1.0
  Cu  Cu7  1  0.656  0.344  0.250  1.0
  Cu  Cu8  1  0.583  0.417  0.967  1.0
  Cu  Cu9  1  0.417  0.583  0.033  1.0
  Cu  Cu10  1  0.417  0.583  0.467  1.0
  Cu  Cu11  1  0.583  0.417  0.533  1.0
  Se  Se12  1  0.762  0.238  0.750  1.0
  Se  Se13  1  0.238  0.762  0.250  1.0
  Se  Se14  1  0.562  0.438  0.388  1.0
  Se  Se15  1  0.438  0.562  0.612  1.0
  Se  Se16  1  0.438  0.562  0.888  1.0
  Se  Se17  1  0.562  0.438  0.112  1.0
  Se  Se18  1  0.831  0.169  0.430  1.0
  Se  Se19  1  0.169  0.831  0.570  1.0
  Se  Se20  1  0.169  0.831  0.930  1.0
  Se  Se21  1  0.831  0.169  0.070  1.0
[/CIF]
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The structure described by CsEr2Cu3Se5 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 10-coordinate geometry to two equivalent Cu(1), two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms. Er(1) is bonded to one Se(1), two equivalent Se(2), and three equivalent Se(3) atoms to form ErSe6 octahedra that share  a cornercorner with one Er(1)Se6 octahedra, corners with four equivalent Cu(2)Se4 tetrahedra, edges with four equivalent Er(1)Se6 octahedra, edges with two equivalent Cu(1)Cs2Se4 tetrahedra, and edges with three equivalent Cu(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Cs(1), two equivalent Se(1), and two equivalent Se(2) atoms to form distorted CuCs2Se4 tetrahedra that share corners with four equivalent Se(3)CsEr3Cu2 octahedra, corners with four equivalent Cu(2)Se4 tetrahedra, edges with four equivalent Er(1)Se6 octahedra, and edges with two equivalent Cu(1)Cs2Se4 tetrahedra. The corner-sharing octahedral tilt angles are 67°. In the second Cu site, Cu(2) is bonded to two equivalent Se(2) and two equivalent Se(3) atoms to form CuSe4 tetrahedra that share corners with four equivalent Er(1)Se6 octahedra, corners with two equivalent Cu(1)Cs2Se4 tetrahedra, corners with two equivalent Cu(2)Se4 tetrahedra, edges with three equivalent Er(1)Se6 octahedra, and  an edgeedge with one Cu(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 15-60°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Er(1), and two equivalent Cu(1) atoms. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent Cs(1), two equivalent Er(1), one Cu(1), and two equivalent Cu(2) atoms. In the third Se site, Se(3) is bonded to one Cs(1), three equivalent Er(1), and two equivalent Cu(2) atoms to form distorted SeCsEr3Cu2 octahedra that share  a cornercorner with one Se(3)CsEr3Cu2 octahedra, corners with two equivalent Cu(1)Cs2Se4 tetrahedra, and edges with four equivalent Se(3)CsEr3Cu2 octahedra. The corner-sharing octahedral tilt angles are 54°. is represented by the CIF card [CIF]
data_CsEr2Cu3Se5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.634
_cell_length_b   7.634
_cell_length_c   17.273
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   148.701
_symmetry_Int_Tables_number   1
_cell_volume   522.895
_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
  Cs  Cs0  1  0.061  0.939  0.750  1.0
  Cs  Cs1  1  0.939  0.061  0.250  1.0
  Er  Er2  1  0.808  0.192  0.591  1.0
  Er  Er3  1  0.192  0.808  0.409  1.0
  Er  Er4  1  0.192  0.808  0.091  1.0
  Er  Er5  1  0.808  0.192  0.909  1.0
  Cu  Cu6  1  0.344  0.656  0.750  1.0
  Cu  Cu7  1  0.656  0.344  0.250  1.0
  Cu  Cu8  1  0.583  0.417  0.967  1.0
  Cu  Cu9  1  0.417  0.583  0.033  1.0
  Cu  Cu10  1  0.417  0.583  0.467  1.0
  Cu  Cu11  1  0.583  0.417  0.533  1.0
  Se  Se12  1  0.762  0.238  0.750  1.0
  Se  Se13  1  0.238  0.762  0.250  1.0
  Se  Se14  1  0.562  0.438  0.388  1.0
  Se  Se15  1  0.438  0.562  0.612  1.0
  Se  Se16  1  0.438  0.562  0.888  1.0
  Se  Se17  1  0.562  0.438  0.112  1.0
  Se  Se18  1  0.831  0.169  0.430  1.0
  Se  Se19  1  0.169  0.831  0.570  1.0
  Se  Se20  1  0.169  0.831  0.930  1.0
  Se  Se21  1  0.831  0.169  0.070  1.0
[/CIF]
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