data_[Mg8Nb4Tl4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Mg  1.3100  1.5000  0.8600
  Nb  1.6000  1.4500  0.8200
  Tl  1.6200  1.9000  1.3325
]
_symmetry_space_group_name_H-M [I-42d]
_cell_length_a [7.8329]
_cell_length_b [7.8329]
_cell_length_c [5.8505]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [122]
_chemical_formula_structural [Mg2NbTl]
_chemical_formula_sum '[Mg8 Nb4 Tl4]'
_cell_volume [358.9485]
_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
[
  Mg  Mg0  8  0.2427  0.7500  0.1250  1
  Nb  Nb1  4  0.0000  0.0000  0.5000  1
  Tl  Tl2  4  0.0000  0.0000  0.0000  1
]