data_[Si8Ni4Se20]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Si  1.9000  1.1000  0.5400
  Ni  1.9100  1.3500  0.7400
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Cmcm]
_cell_length_a [3.4402]
_cell_length_b [13.1564]
_cell_length_c [16.2957]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [63]
_chemical_formula_structural [Si2NiSe5]
_chemical_formula_sum '[Si8 Ni4 Se20]'
_cell_volume [737.5557]
_cell_formula_units_Z [4]
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
[
  Si  Si0  8  0.0000  0.2855  0.5852  1
  Ni  Ni1  4  0.0000  0.2101  0.2500  1
  Se  Se2  8  0.0000  0.1002  0.1340  1
  Se  Se3  8  0.0000  0.3457  0.0556  1
  Se  Se4  4  0.0000  0.1757  0.7500  1
]