The material structure described by ErSe2 crystallizes in the orthorhombic Immm space group. Er(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to four equivalent Er(1) atoms to form a mixture of distorted corner and edge-sharing SeEr4 trigonal pyramids. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to four equivalent Er(1) and two equivalent Se(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_ErSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.506
_cell_length_b   7.506
_cell_length_c   7.506
_cell_angle_alpha   149.338
_cell_angle_beta   137.607
_cell_angle_gamma   53.221
_symmetry_Int_Tables_number   1
_cell_volume   144.591
_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
  Er  Er0  1  0.858  0.858  0.000  1.0
  Er  Er1  1  0.142  0.142  0.000  1.0
  Se  Se2  1  0.713  0.213  0.500  1.0
  Se  Se3  1  0.287  0.787  0.500  1.0
  Se  Se4  1  0.758  0.500  0.258  1.0
  Se  Se5  1  0.242  0.500  0.742  1.0
[/CIF]
.
The material structure described by ErSe2 crystallizes in the orthorhombic Immm space group. Er(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to four equivalent Er(1) atoms to form a mixture of distorted corner and edge-sharing SeEr4 trigonal pyramids. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to four equivalent Er(1) and two equivalent Se(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_ErSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.506
_cell_length_b   7.506
_cell_length_c   7.506
_cell_angle_alpha   149.338
_cell_angle_beta   137.607
_cell_angle_gamma   53.221
_symmetry_Int_Tables_number   1
_cell_volume   144.591
_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
  Er  Er0  1  0.858  0.858  0.000  1.0
  Er  Er1  1  0.142  0.142  0.000  1.0
  Se  Se2  1  0.713  0.213  0.500  1.0
  Se  Se3  1  0.287  0.787  0.500  1.0
  Se  Se4  1  0.758  0.500  0.258  1.0
  Se  Se5  1  0.242  0.500  0.742  1.0
[/CIF]
.