data_[Ca4Si2Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Ca  1.0000  1.8000  1.1400
  Si  1.9000  1.1000  0.5400
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [P2_1/m]
_cell_length_a [6.8022]
_cell_length_b [6.9796]
_cell_length_c [8.0462]
_cell_angle_alpha [90.0000]
_cell_angle_beta [107.2791]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [11]
_chemical_formula_structural [Ca2SiSe4]
_chemical_formula_sum '[Ca4 Si2 Se8]'
_cell_volume [364.7659]
_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
[
  Ca  Ca0  2  0.2615  0.2500  0.4409  1.0
  Ca  Ca1  2  0.2695  0.2500  0.9430  1.0
  Si  Si2  2  0.2621  0.7500  0.1921  1.0
  Se  Se3  4  0.4914  0.0006  0.2523  1.0
  Se  Se4  2  0.0753  0.7500  0.3846  1.0
  Se  Se5  2  0.0814  0.7500  0.9059  1.0
]