data_[Na4Ca8Tl4O16]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Ca  1.0000  1.8000  1.1400
  Tl  1.6200  1.9000  1.3325
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [Imma]
_cell_length_a [6.9031]
_cell_length_b [6.9425]
_cell_length_c [9.3547]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [74]
_chemical_formula_structural [NaCa2TlO4]
_chemical_formula_sum '[Na4 Ca8 Tl4 O16]'
_cell_volume [448.3224]
_cell_formula_units_Z [4]
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
[
  Na  Na0  4  0.2500  0.2500  0.2500  1
  Ca  Ca1  4  0.0000  0.0000  0.5000  1
  Ca  Ca2  4  0.2500  0.2500  0.7500  1
  Tl  Tl3  4  0.0000  0.0000  0.0000  1
  O  O4  8  0.0000  0.0139  0.7604  1
  O  O5  8  0.2408  0.7500  0.4984  1
]