data_[Na4Mg2Cu4Se8]
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 [C2/m]
_cell_length_a [14.8397]
_cell_length_b [3.9105]
_cell_length_c [6.9351]
_cell_angle_alpha [90.0000]
_cell_angle_beta [111.2570]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Na2Mg(CuSe2)2]
_chemical_formula_sum '[Na4 Mg2 Cu4 Se8]'
_cell_volume [375.0701]
_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  4  0.1271  0.0000  0.5602  1.0
  Mg  Mg1  2  0.0000  0.0000  0.0000  1.0
  Cu  Cu2  4  0.1836  0.5000  0.9830  1.0
  Se  Se3  4  0.0157  0.5000  0.7520  1.0
  Se  Se4  4  0.2062  0.0000  0.2053  1.0
]