data_[Mg20Sn4Hg8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Mg  1.3100  1.5000  0.8600
  Sn  1.9600  1.4500  0.8300
  Hg  2.0000  1.5000  1.2450
]
_symmetry_space_group_name_H-M [I4/mcm]
_cell_length_a [7.5194]
_cell_length_b [7.5194]
_cell_length_c [12.9243]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [140]
_chemical_formula_structural [Mg5SnHg2]
_chemical_formula_sum '[Mg20 Sn4 Hg8]'
_cell_volume [730.7522]
_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  16  0.1503  0.3497  0.6552  1
  Mg  Mg1  4  0.0000  0.0000  0.0000  1
  Sn  Sn2  4  0.0000  0.0000  0.2500  1
  Hg  Hg3  8  0.1484  0.3516  0.0000  1
]