data_[Cu2Ag2Se8]
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 [P2/c]
_cell_length_a [8.2613]
_cell_length_b [4.2702]
_cell_length_c [9.1660]
_cell_angle_alpha [90.0000]
_cell_angle_beta [121.5874]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [13]
_chemical_formula_structural [CuAgSe4]
_chemical_formula_sum '[Cu2 Ag2 Se8]'
_cell_volume [275.4441]
_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  0.0000  0.0000  0.0000  1.0
  Ag  Ag1  2  0.5000  0.4966  0.2500  1.0
  Se  Se2  4  0.1920  0.3590  0.9535  1.0
  Se  Se3  4  0.2748  0.0442  0.7811  1.0
]