data_[Na2Mn2Si2O8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Mn  1.5500  1.4000  0.6483
  Si  1.9000  1.1000  0.5400
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [I-4]
_cell_length_a [5.3894]
_cell_length_b [5.3894]
_cell_length_c [6.8497]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [82]
_chemical_formula_structural [NaMnSiO4]
_chemical_formula_sum '[Na2 Mn2 Si2 O8]'
_cell_volume [198.9530]
_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  0.0000  0.0000  0.0000  1
  Mn  Mn1  2  0.0000  0.0000  0.5000  1
  Si  Si2  2  0.0000  0.5000  0.7500  1
  O  O3  8  0.1439  0.2903  0.6163  1
]