data_[Fe2Cu6Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Fe  1.8300  1.4000  0.8525
  Cu  1.9000  1.3500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Pmn2_1]
_cell_length_a [7.6765]
_cell_length_b [6.6439]
_cell_length_c [6.5533]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [31]
_chemical_formula_structural [FeCu3Se4]
_chemical_formula_sum '[Fe2 Cu6 Se8]'
_cell_volume [334.2309]
_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
[
  Fe  Fe0  2  0.0000  0.1701  0.9999  1.0
  Cu  Cu1  4  0.2490  0.6690  0.9951  1.0
  Cu  Cu2  2  0.0000  0.8380  0.4963  1.0
  Se  Se3  4  0.2478  0.3318  0.1287  1.0
  Se  Se4  2  0.0000  0.1714  0.6416  1.0
  Se  Se5  2  0.0000  0.8426  0.1298  1.0
]