data_[Pm2Nd2Cu4Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Pm  1.1300  1.8500  1.1100
  Nd  1.1400  1.8500  1.2765
  Cu  1.9000  1.3500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [I222]
_cell_length_a [6.9390]
_cell_length_b [6.9786]
_cell_length_c [7.9569]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [23]
_chemical_formula_structural [PmNd(CuSe2)2]
_chemical_formula_sum '[Pm2 Nd2 Cu4 Se8]'
_cell_volume [385.3068]
_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
[
  Pm  Pm0  2  0.0000  0.0000  0.5000  1
  Nd  Nd1  2  0.0000  0.0000  0.0000  1
  Cu  Cu2  4  0.0000  0.5000  0.1587  1
  Se  Se3  8  0.2399  0.2654  0.7989  1
]