data_[Na2Cu4Se4O20]
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
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [9.5539]
_cell_length_b [6.1943]
_cell_length_c [8.3306]
_cell_angle_alpha [90.0000]
_cell_angle_beta [122.5157]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [NaCu2(SeO5)2]
_chemical_formula_sum '[Na2 Cu4 Se4 O20]'
_cell_volume [415.7173]
_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  0.0000  0.0000  0.0000  1.0
  Cu  Cu1  4  0.2500  0.2500  0.5000  1.0
  Se  Se2  4  0.0793  0.5000  0.7960  1.0
  O  O3  8  0.0445  0.2733  0.2617  1.0
  O  O4  4  0.1776  0.0000  0.5402  1.0
  O  O5  4  0.1777  0.5000  0.6815  1.0
  O  O6  4  0.2074  0.5000  0.0271  1.0
]