data_[Na2Mg2Cu2Se4]
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
  Cu  1.9000  1.3500  0.8200
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P2/c]
_cell_length_a [6.8386]
_cell_length_b [5.1530]
_cell_length_c [6.9766]
_cell_angle_alpha [90.0000]
_cell_angle_beta [101.0949]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [13]
_chemical_formula_structural [NaMgCuSe2]
_chemical_formula_sum '[Na2 Mg2 Cu2 Se4]'
_cell_volume [241.2575]
_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  0.5000  0.1718  0.2500  1
  Mg  Mg1  2  0.0000  0.4966  0.7500  1
  Cu  Cu2  2  0.0000  0.0000  0.0000  1
  Se  Se3  4  0.2519  0.2940  0.5456  1
]