data_[Tb8Mg4Se16]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Tb  1.1000  1.7500  0.9815
  Mg  1.3100  1.5000  0.8600
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Pnma]
_cell_length_a [8.1731]
_cell_length_b [7.7608]
_cell_length_c [12.1305]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [62]
_chemical_formula_structural [Tb2MgSe4]
_chemical_formula_sum '[Tb8 Mg4 Se16]'
_cell_volume [769.4383]
_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
[
  Tb  Tb0  4  0.0557  0.2500  0.0222  1
  Tb  Tb1  4  0.0584  0.7500  0.3120  1
  Mg  Mg2  4  0.1764  0.2500  0.4045  1
  Se  Se3  8  0.1283  0.5022  0.8421  1
  Se  Se4  4  0.1148  0.7500  0.5436  1
  Se  Se5  4  0.2316  0.7500  0.1124  1
]