data_[Na4Mg2Si2O8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Mg  1.3100  1.5000  0.8600
  Si  1.9000  1.1000  0.5400
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [Pc]
_cell_length_a [5.3356]
_cell_length_b [5.5714]
_cell_length_c [8.8239]
_cell_angle_alpha [90.0000]
_cell_angle_beta [127.0221]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [7]
_chemical_formula_structural [Na2MgSiO4]
_chemical_formula_sum '[Na4 Mg2 Si2 O8]'
_cell_volume [209.4266]
_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  0.4863  0.1830  0.9946  1.0
  Na  Na1  2  0.7379  0.3329  0.7496  1.0
  Mg  Mg2  2  0.0016  0.1859  0.5004  1.0
  Si  Si3  2  0.2527  0.3126  0.2476  1.0
  O  O4  2  0.1482  0.4007  0.7170  1.0
  O  O5  2  0.3016  0.2103  0.4399  1.0
  O  O6  2  0.5888  0.2874  0.2776  1.0
  O  O7  2  0.9824  0.1549  0.0569  1.0
]