data_[Pm4Er8Se18]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Pm  1.1300  1.8500  1.1100
  Er  1.2400  1.7500  1.0300
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P-3c1]
_cell_length_a [7.2324]
_cell_length_b [7.2324]
_cell_length_c [19.4810]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [165]
_chemical_formula_structural [Pm2Er4Se9]
_chemical_formula_sum '[Pm4 Er8 Se18]'
_cell_volume [882.4755]
_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  4  0.0000  0.0000  0.1491  1
  Er  Er1  4  0.3333  0.6667  0.4871  1
  Er  Er2  4  0.3333  0.6667  0.6817  1
  Se  Se3  12  0.0258  0.3732  0.5836  1
  Se  Se4  6  0.0000  0.3115  0.2500  1
]