data_[Cu4Ni8Se20]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Cu  1.9000  1.3500  0.8200
  Ni  1.9100  1.3500  0.7400
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Pnnm]
_cell_length_a [9.7469]
_cell_length_b [10.2548]
_cell_length_c [7.1542]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [58]
_chemical_formula_structural [CuNi2Se5]
_chemical_formula_sum '[Cu4 Ni8 Se20]'
_cell_volume [715.0790]
_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  0.2309  0.2652  0.0000  1
  Ni  Ni1  4  0.0000  0.0000  0.2601  1
  Ni  Ni2  4  0.1266  0.3584  0.5000  1
  Se  Se3  8  0.0802  0.2229  0.2486  1
  Se  Se4  4  0.1178  0.5833  0.5000  1
  Se  Se5  4  0.1361  0.9116  0.0000  1
  Se  Se6  4  0.1660  0.9696  0.5000  1
]