data_[Er4Cu2Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Er  1.2400  1.7500  1.0300
  Cu  1.9000  1.3500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P2_1/m]
_cell_length_a [6.9434]
_cell_length_b [5.8848]
_cell_length_c [7.9643]
_cell_angle_alpha [90.0000]
_cell_angle_beta [106.5425]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [11]
_chemical_formula_structural [Er2CuSe4]
_chemical_formula_sum '[Er4 Cu2 Se8]'
_cell_volume [311.9573]
_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  2  0.2277  0.7500  0.9297  1.0
  Er  Er1  2  0.2451  0.7500  0.4368  1.0
  Cu  Cu2  2  0.2396  0.2500  0.1833  1.0
  Se  Se3  4  0.4831  0.0088  0.7470  1.0
  Se  Se4  2  0.0658  0.2500  0.8807  1.0
  Se  Se5  2  0.0701  0.2500  0.4029  1.0
]