data_[Cu4Se4]
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 [P-1]
_cell_length_a [3.6275]
_cell_length_b [6.2023]
_cell_length_c [8.7521]
_cell_angle_alpha [108.4752]
_cell_angle_beta [90.1682]
_cell_angle_gamma [106.7241]
_symmetry_Int_Tables_number [2]
_chemical_formula_structural [CuSe]
_chemical_formula_sum '[Cu4 Se4]'
_cell_volume [177.9031]
_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
[
  Cu  Cu0  2  0.0170  0.0049  0.2352  1.0
  Cu  Cu1  2  0.3174  0.6201  0.9428  1.0
  Se  Se2  2  0.3490  0.7215  0.7084  1.0
  Se  Se3  2  0.3856  0.7340  0.2251  1.0
]