data_[Mg4Si4Se4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Mg  1.3100  1.5000  0.8600
  Si  1.9000  1.1000  0.5400
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Cc]
_cell_length_a [5.9251]
_cell_length_b [13.3690]
_cell_length_c [3.9329]
_cell_angle_alpha [90.0000]
_cell_angle_beta [105.1357]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [9]
_chemical_formula_structural [MgSiSe]
_chemical_formula_sum '[Mg4 Si4 Se4]'
_cell_volume [300.7306]
_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  0.4504  0.6617  0.0124  1
  Si  Si1  4  0.0759  0.4511  0.2635  1
  Se  Se2  4  0.2516  0.8335  0.1281  1
]