data_[Rb4Er2Ta4O14]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  Er  1.2400  1.7500  1.0300
  Ta  1.5000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [I4/mmm]
_cell_length_a [4.0212]
_cell_length_b [4.0212]
_cell_length_c [22.6366]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [139]
_chemical_formula_structural [Rb2ErTa2O7]
_chemical_formula_sum '[Rb4 Er2 Ta4 O14]'
_cell_volume [366.0386]
_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
[
  Rb  Rb0  4  0.0000  0.0000  0.1919  1
  Er  Er1  2  0.0000  0.0000  0.0000  1
  Ta  Ta2  4  0.0000  0.0000  0.4104  1
  O  O3  8  0.0000  0.5000  0.0743  1
  O  O4  4  0.0000  0.0000  0.3269  1
  O  O5  2  0.0000  0.0000  0.5000  1
]