data_[Cu4Ag4Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Cu  1.9000  1.3500  0.8200
  Ag  1.9300  1.6000  1.0867
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [I-42d]
_cell_length_a [5.8747]
_cell_length_b [5.8747]
_cell_length_c [10.9986]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [122]
_chemical_formula_structural [CuAgSe2]
_chemical_formula_sum '[Cu4 Ag4 Se8]'
_cell_volume [379.5848]
_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  4  0.0000  0.0000  0.5000  1.0
  Ag  Ag1  4  0.0000  0.0000  0.0000  1.0
  Se  Se2  8  0.2143  0.7500  0.6250  1.0
]