data_[Cu4Se2]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Cu  1.9000  1.3500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Pm]
_cell_length_a [17.0644]
_cell_length_b [4.9080]
_cell_length_c [17.0644]
_cell_angle_alpha [90.0000]
_cell_angle_beta [120.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [6]
_chemical_formula_structural [Cu2Se]
_chemical_formula_sum '[Cu4 Se2]'
_cell_volume [1237.6926]
_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
[
  Cu  Cu0  2  0.5018  0.2500  0.4997  1
  Cu  Cu1  1  0.3878  0.5000  0.5131  1
  Cu  Cu2  1  0.3991  0.0000  0.5306  1
  Se  Se3  1  0.5822  0.5000  0.4433  1
  Se  Se4  1  0.6272  0.0000  0.5136  1
]