data_[Na2Tb2Si2O8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Tb  1.1000  1.7500  0.9815
  Si  1.9000  1.1000  0.5400
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [P2_1/m]
_cell_length_a [5.7620]
_cell_length_b [5.5224]
_cell_length_c [6.8769]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.4035]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [11]
_chemical_formula_structural [NaTbSiO4]
_chemical_formula_sum '[Na2 Tb2 Si2 O8]'
_cell_volume [218.8156]
_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
[
  Na  Na0  2  0.4030  0.7500  0.8642  1.0
  Tb  Tb1  2  0.1963  0.7500  0.4267  1.0
  Si  Si2  2  0.3088  0.2500  0.6581  1.0
  O  O3  4  0.1299  0.0171  0.6762  1.0
  O  O4  2  0.4235  0.2500  0.4400  1.0
  O  O5  2  0.4733  0.7500  0.1879  1.0
]