data_[Ca2Mg8Si4]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Ca  1.0000  1.8000  1.1400
  Mg  1.3100  1.5000  0.8600
  Si  1.9000  1.1000  0.5400
]
_symmetry_space_group_name_H-M [P4_2/mnm]
_cell_length_a [8.4487]
_cell_length_b [8.4487]
_cell_length_c [4.2815]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [136]
_chemical_formula_structural [Ca(Mg2Si)2]
_chemical_formula_sum '[Ca2 Mg8 Si4]'
_cell_volume [305.6193]
_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
[
  Ca  Ca0  2  0.0000  0.0000  0.5000  1
  Mg  Mg1  8  0.0907  0.3352  0.0000  1
  Si  Si2  4  0.2079  0.7921  0.0000  1
]