data_[Na2Cu2As2Se6]
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
  As  2.1800  1.1500  0.6600
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P2_1/m]
_cell_length_a [8.6361]
_cell_length_b [3.8667]
_cell_length_c [8.8142]
_cell_angle_alpha [90.0000]
_cell_angle_beta [104.6674]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [11]
_chemical_formula_structural [NaCuAsSe3]
_chemical_formula_sum '[Na2 Cu2 As2 Se6]'
_cell_volume [284.7405]
_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  0.1888  0.2500  0.2372  1.0
  Cu  Cu1  2  0.0722  0.2500  0.5871  1.0
  As  As2  2  0.3364  0.7500  0.8683  1.0
  Se  Se3  2  0.1245  0.2500  0.8760  1.0
  Se  Se4  2  0.2181  0.7500  0.5222  1.0
  Se  Se5  2  0.4448  0.7500  0.1613  1.0
]