data_[Na4Cu4Ni2Se8]
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
  Ni  1.9100  1.3500  0.7400
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [14.5186]
_cell_length_b [3.8113]
_cell_length_c [6.8368]
_cell_angle_alpha [90.0000]
_cell_angle_beta [111.9567]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Na2Cu2NiSe4]
_chemical_formula_sum '[Na4 Cu4 Ni2 Se8]'
_cell_volume [350.8736]
_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  0.1347  0.0000  0.5708  1.0
  Cu  Cu1  4  0.1881  0.5000  0.9725  1.0
  Ni  Ni2  2  0.0000  0.0000  0.0000  1.0
  Se  Se3  4  0.0131  0.5000  0.7735  1.0
  Se  Se4  4  0.1886  0.0000  0.1961  1.0
]