data_[Na2Se2]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P-1]
_cell_length_a [4.9765]
_cell_length_b [5.0809]
_cell_length_c [5.6113]
_cell_angle_alpha [65.6768]
_cell_angle_beta [85.6520]
_cell_angle_gamma [63.7082]
_symmetry_Int_Tables_number [2]
_chemical_formula_structural [NaSe]
_chemical_formula_sum '[Na2 Se2]'
_cell_volume [114.9218]
_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  0.2357  0.1013  0.7418  1
  Se  Se1  2  0.4217  0.5261  0.2831  1
]