data_[Mg2Nb4Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Mg  1.3100  1.5000  0.8600
  Nb  1.6000  1.4500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [14.3908]
_cell_length_b [3.5336]
_cell_length_c [6.3837]
_cell_angle_alpha [90.0000]
_cell_angle_beta [114.0960]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Mg(NbSe2)2]
_chemical_formula_sum '[Mg2 Nb4 Se8]'
_cell_volume [296.3277]
_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
[
  Mg  Mg0  2  0.0000  0.0000  0.0000  1.0
  Nb  Nb1  4  0.2456  0.5000  0.6834  1.0
  Se  Se2  4  0.1076  0.0000  0.4579  1.0
  Se  Se3  4  0.1436  0.5000  0.9819  1.0
]