data_[Na2Mg2Al2Se6]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Mg  1.3100  1.5000  0.8600
  Al  1.6100  1.2500  0.6750
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P2_1/m]
_cell_length_a [8.1534]
_cell_length_b [3.9045]
_cell_length_c [10.8088]
_cell_angle_alpha [90.0000]
_cell_angle_beta [107.5168]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [11]
_chemical_formula_structural [NaMgAlSe3]
_chemical_formula_sum '[Na2 Mg2 Al2 Se6]'
_cell_volume [328.1385]
_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
[
  Na  Na0  2  0.2012  0.2500  0.1654  1.0
  Mg  Mg1  2  0.3557  0.7500  0.8986  1.0
  Al  Al2  2  0.0856  0.2500  0.6220  1.0
  Se  Se3  2  0.0863  0.2500  0.8375  1.0
  Se  Se4  2  0.2075  0.7500  0.5388  1.0
  Se  Se5  2  0.4543  0.7500  0.1528  1.0
]