data_[Mg4Be8Se12]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Mg  1.3100  1.5000  0.8600
  Be  1.5700  1.0500  0.5900
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Cc]
_cell_length_a [6.6577]
_cell_length_b [11.6549]
_cell_length_c [6.5875]
_cell_angle_alpha [90.0000]
_cell_angle_beta [108.4263]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [9]
_chemical_formula_structural [MgBe2Se3]
_chemical_formula_sum '[Mg4 Be8 Se12]'
_cell_volume [484.9511]
_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
[
  Mg  Mg0  4  0.4892  0.5879  0.9985  1
  Be  Be1  4  0.4852  0.2430  0.9914  1
  Be  Be2  4  0.4915  0.0832  0.4924  1
  Se  Se3  4  0.3432  0.3980  0.0931  1
  Se  Se4  4  0.3476  0.2306  0.6250  1
  Se  Se5  4  0.3957  0.9197  0.6283  1
]