data_[Be2Fe2Se4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Be  1.5700  1.0500  0.5900
  Fe  1.8300  1.4000  0.8525
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P1]
_cell_length_a [3.6428]
_cell_length_b [7.3934]
_cell_length_c [19.0163]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [97.9944]
_symmetry_Int_Tables_number [1]
_chemical_formula_structural [BeFeSe2]
_chemical_formula_sum '[Be2 Fe2 Se4]'
_cell_volume [507.1847]
_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
[
  Be  Be0  1  0.4570  0.7482  0.4835  1
  Be  Be1  1  0.8908  0.5411  0.4458  1
  Fe  Fe2  1  0.3638  0.4641  0.5373  1
  Fe  Fe3  1  0.9083  0.6720  0.5635  1
  Se  Se4  1  0.0564  0.8394  0.4109  1
  Se  Se5  1  0.3481  0.3903  0.4151  1
  Se  Se6  1  0.8488  0.3979  0.6221  1
  Se  Se7  1  0.8750  0.9755  0.5218  1
]