data_[Mg6Se6]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Mg  1.3100  1.5000  0.8600
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Pmmn]
_cell_length_a [4.2293]
_cell_length_b [13.0617]
_cell_length_c [6.3115]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [59]
_chemical_formula_structural [MgSe]
_chemical_formula_sum '[Mg6 Se6]'
_cell_volume [348.6554]
_cell_formula_units_Z [6]
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  0.0000  0.3500  0.0740  1
  Mg  Mg1  2  0.0000  0.0000  0.4222  1
  Se  Se2  4  0.0000  0.1548  0.1666  1
  Se  Se3  2  0.0000  0.5000  0.3415  1
]