data_[Hg4H2C8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Hg  2.0000  1.5000  1.2450
  H  2.2000  0.2500  0.0000
  C  2.5500  0.7000  0.3000
]
_symmetry_space_group_name_H-M [I4/mmm]
_cell_length_a [2.6078]
_cell_length_b [2.6078]
_cell_length_c [25.5078]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [139]
_chemical_formula_structural [Hg2HC4]
_chemical_formula_sum '[Hg4 H2 C8]'
_cell_volume [173.4679]
_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
[
  Hg  Hg0  4  0.0000  0.0000  0.3672  1
  H  H1  2  0.0000  0.0000  0.0000  1
  C  C2  4  0.0000  0.0000  0.2512  1
  C  C3  4  0.0000  0.5000  0.0000  1
]