The material described by Er2Se3 crystallizes in the orthorhombic Fddd space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form a mixture of corner and edge-sharing ErSe6 octahedra. The corner-sharing octahedral tilt angles range from 3-4°. In the second Er site, Er(2) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form a mixture of corner and edge-sharing ErSe6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to two equivalent Er(1) and two equivalent Er(2) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to two equivalent Er(1) and two equivalent Er(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Er2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.992
_cell_length_b   6.992
_cell_length_c   12.771
_cell_angle_alpha   100.635
_cell_angle_beta   100.635
_cell_angle_gamma   109.013
_symmetry_Int_Tables_number   1
_cell_volume   559.665
_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
  Er  Er0  1  0.128  0.378  0.755  1.0
  Er  Er1  1  0.622  0.872  0.745  1.0
  Er  Er2  1  0.872  0.622  0.245  1.0
  Er  Er3  1  0.378  0.128  0.255  1.0
  Er  Er4  1  0.791  0.041  0.082  1.0
  Er  Er5  1  0.959  0.209  0.418  1.0
  Er  Er6  1  0.209  0.959  0.918  1.0
  Er  Er7  1  0.041  0.791  0.582  1.0
  Se  Se8  1  0.539  0.283  0.088  1.0
  Se  Se9  1  0.195  0.951  0.412  1.0
  Se  Se10  1  0.717  0.461  0.412  1.0
  Se  Se11  1  0.049  0.805  0.088  1.0
  Se  Se12  1  0.461  0.717  0.912  1.0
  Se  Se13  1  0.805  0.049  0.588  1.0
  Se  Se14  1  0.283  0.539  0.588  1.0
  Se  Se15  1  0.951  0.195  0.912  1.0
  Se  Se16  1  0.883  0.633  0.750  1.0
  Se  Se17  1  0.367  0.117  0.750  1.0
  Se  Se18  1  0.117  0.367  0.250  1.0
  Se  Se19  1  0.633  0.883  0.250  1.0
[/CIF]
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The material described by Er2Se3 crystallizes in the orthorhombic Fddd space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form a mixture of corner and edge-sharing ErSe6 octahedra. The corner-sharing octahedral tilt angles range from 3-4°. In the second Er site, Er(2) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form a mixture of corner and edge-sharing ErSe6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to two equivalent Er(1) and two equivalent Er(2) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to two equivalent Er(1) and two equivalent Er(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Er2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.992
_cell_length_b   6.992
_cell_length_c   12.771
_cell_angle_alpha   100.635
_cell_angle_beta   100.635
_cell_angle_gamma   109.013
_symmetry_Int_Tables_number   1
_cell_volume   559.665
_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
  Er  Er0  1  0.128  0.378  0.755  1.0
  Er  Er1  1  0.622  0.872  0.745  1.0
  Er  Er2  1  0.872  0.622  0.245  1.0
  Er  Er3  1  0.378  0.128  0.255  1.0
  Er  Er4  1  0.791  0.041  0.082  1.0
  Er  Er5  1  0.959  0.209  0.418  1.0
  Er  Er6  1  0.209  0.959  0.918  1.0
  Er  Er7  1  0.041  0.791  0.582  1.0
  Se  Se8  1  0.539  0.283  0.088  1.0
  Se  Se9  1  0.195  0.951  0.412  1.0
  Se  Se10  1  0.717  0.461  0.412  1.0
  Se  Se11  1  0.049  0.805  0.088  1.0
  Se  Se12  1  0.461  0.717  0.912  1.0
  Se  Se13  1  0.805  0.049  0.588  1.0
  Se  Se14  1  0.283  0.539  0.588  1.0
  Se  Se15  1  0.951  0.195  0.912  1.0
  Se  Se16  1  0.883  0.633  0.750  1.0
  Se  Se17  1  0.367  0.117  0.750  1.0
  Se  Se18  1  0.117  0.367  0.250  1.0
  Se  Se19  1  0.633  0.883  0.250  1.0
[/CIF]
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