data_[K2Er2Si2Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  K  0.8200  2.2000  1.5200
  Er  1.2400  1.7500  1.0300
  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 [6.6509]
_cell_length_b [6.9681]
_cell_length_c [9.0882]
_cell_angle_alpha [90.0000]
_cell_angle_beta [107.6485]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [11]
_chemical_formula_structural [KErSiSe4]
_chemical_formula_sum '[K2 Er2 Si2 Se8]'
_cell_volume [401.3574]
_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
[
  K  K0  2  0.2514  0.2500  0.0598  1.0
  Er  Er1  2  0.2272  0.2500  0.5511  1.0
  Si  Si2  2  0.2254  0.7500  0.3307  1.0
  Se  Se3  4  0.0065  0.5038  0.7097  1.0
  Se  Se4  2  0.4243  0.7500  0.1682  1.0
  Se  Se5  2  0.4330  0.7500  0.5800  1.0
]