data_[Na4Cu4Se4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Cu  1.9000  1.3500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [10.4426]
_cell_length_b [4.0964]
_cell_length_c [6.5541]
_cell_angle_alpha [90.0000]
_cell_angle_beta [103.1469]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [NaCuSe]
_chemical_formula_sum '[Na4 Cu4 Se4]'
_cell_volume [273.0175]
_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
[
  Na  Na0  4  0.0997  0.5000  0.3379  1.0
  Cu  Cu1  4  0.2114  0.5000  0.9026  1.0
  Se  Se2  4  0.1326  0.0000  0.7305  1.0
]