data_HgC
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.49
_cell_length_b   6.49
_cell_length_c   6.49
_cell_angle_alpha   156.56
_cell_angle_beta   123.78
_cell_angle_gamma   61.74
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HgC
_chemical_formula_sum   'Hg2 C2'
_cell_volume   89.76
_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  Hg2  1  0.0  0.59  0.88  1.0
  Hg  Hg3  1  0.32  0.47  0.69  1.0
  C  C0  1  0.32  0.53  0.79  1.0
  C  C1  1  0.0  0.53  0.78  1.0

data_HgC
_symmetry_space_group_name_H-M   P-1
_cell_length_a   2.64
_cell_length_b   6.11
_cell_length_c   6.49
_cell_angle_alpha   118.11
_cell_angle_beta   101.72
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   HgC
_chemical_formula_sum   'Hg2 C2'
_cell_volume   89.76
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-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  2  0.26  0.54  0.7  1.0
  C  C1  2  0.15  0.5  0.65  1.0

Hg Hg C C
CHg crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two mercury, hydromethyl- molecules. Hg(1) is bonded in a single-bond geometry to one C(1) atom. The Hg(1)-C(1) bond length is 0.36 Å. C(1) is bonded in a single-bond geometry to one Hg(1) atom.