data_Hg3C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.23
_cell_length_b   5.23
_cell_length_c   5.23
_cell_angle_alpha   131.39
_cell_angle_beta   131.39
_cell_angle_gamma   71.2
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Hg3C
_chemical_formula_sum   'Hg3 C1'
_cell_volume   78.87
_cell_formula_units_Z   1
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  Hg1  1  0.0  0.15  0.13  1.0
  Hg  Hg2  1  0.15  0.0  0.13  1.0
  Hg  Hg3  1  0.0  0.0  0.25  1.0
  C  C0  1  0.0  0.0  0.0  1.0

data_Hg3C
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.09
_cell_length_b   6.09
_cell_length_c   5.23
_cell_angle_alpha   90.0
_cell_angle_beta   125.6
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Hg3C
_chemical_formula_sum   'Hg6 C2'
_cell_volume   157.73
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  0.42  0.42  0.97  1.0
  Hg  Hg1  2  0.0  0.0  0.25  1.0
  C  C2  2  0.0  0.0  0.0  1.0

Hg Hg Hg C
Hg Hg Hg C 0 3 o o o 0 2 o o o 1 3 o o o 1 2 o o o 2 3 o o o 