data_[Ca6Er2Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Ca  1.0000  1.8000  1.1400
  Er  1.2400  1.7500  1.0300
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [Cmmm]
_cell_length_a [8.3331]
_cell_length_b [11.7541]
_cell_length_c [4.1445]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [65]
_chemical_formula_structural [Ca3ErSe4]
_chemical_formula_sum '[Ca6 Er2 Se8]'
_cell_volume [405.9413]
_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  4  0.2500  0.2500  0.0000  1.0
  Ca  Ca1  2  0.0000  0.5000  0.5000  1.0
  Er  Er2  2  0.0000  0.0000  0.5000  1.0
  Se  Se3  4  0.0000  0.2458  0.5000  1.0
  Se  Se4  4  0.2430  0.0000  0.0000  1.0
]