data_[K4Er2Al2O8]
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
  Al  1.6100  1.2500  0.6750
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [I-4]
_cell_length_a [5.7776]
_cell_length_b [5.7776]
_cell_length_c [8.5090]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [82]
_chemical_formula_structural [K2ErAlO4]
_chemical_formula_sum '[K4 Er2 Al2 O8]'
_cell_volume [284.0317]
_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  0.0000  0.0000  0.0000  1
  K  K1  2  0.0000  0.5000  0.7500  1
  Er  Er2  2  0.0000  0.5000  0.2500  1
  Al  Al3  2  0.0000  0.0000  0.5000  1
  O  O4  8  0.1343  0.2227  0.3847  1
]