data_SiHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.52
_cell_length_b   5.52
_cell_length_c   5.52
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SiHg
_chemical_formula_sum   'Si4 Hg4'
_cell_volume   168.36
_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
  Si  Si4  1  0.18  0.94  0.34  1.0
  Si  Si5  1  0.58  0.58  0.58  1.0
  Si  Si6  1  0.34  0.18  0.94  1.0
  Si  Si7  1  0.94  0.34  0.18  1.0
  Hg  Hg0  1  0.48  0.24  0.04  1.0
  Hg  Hg1  1  0.28  0.28  0.28  1.0
  Hg  Hg2  1  0.04  0.48  0.24  1.0
  Hg  Hg3  1  0.24  0.04  0.48  1.0

data_SiHg
_symmetry_space_group_name_H-M   R3
_cell_length_a   7.81
_cell_length_b   7.81
_cell_length_c   9.56
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   146
_chemical_formula_structural   SiHg
_chemical_formula_sum   'Si12 Hg12'
_cell_volume   505.08
_cell_formula_units_Z   12
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  'x+1/3, y+2/3, z+2/3'
  5  '-y+1/3, x-y+2/3, z+2/3'
  6  '-x+y+1/3, -x+2/3, z+2/3'
  7  'x+2/3, y+1/3, z+1/3'
  8  '-y+2/3, x-y+1/3, z+1/3'
  9  '-x+y+2/3, -x+1/3, z+1/3'
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
  Si  Si0  9  0.03  0.82  0.16  1.0
  Si  Si1  3  0.0  0.0  0.58  1.0
  Hg  Hg2  9  0.13  0.68  0.92  1.0
  Hg  Hg3  3  0.0  0.0  0.28  1.0

Si Si Si Si Hg Hg Hg Hg
Si Si Si Si Hg Hg Hg Hg 0 7 o + o 0 1 o o o 0 5 o + o 1 7 o o o 1 7 o + o 1 6 o o o 1 6 + o o 1 5 o o o 1 4 o o o 1 4 o o + 1 2 o o o 1 3 o o o 2 4 o o + 2 5 o o + 3 6 + o o 3 5 + o o 4 5 o o o 5 7 o o o 5 6 o o o 
HgSi is alpha Po structured and crystallizes in the trigonal R3 space group. The structure is zero-dimensional and consists of three HgSi clusters. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a distorted single-bond geometry to one Hg(2) and one Si(1) atom. The Hg(1)-Hg(2) bond length is 1.72 Å. The Hg(1)-Si(1) bond length is 0.99 Å. In the second Hg site, Hg(2) is bonded in a 7-coordinate geometry to three equivalent Hg(1), one Si(2), and three equivalent Si(1) atoms. The Hg(2)-Si(2) bond length is 2.80 Å. All Hg(2)-Si(1) bond lengths are 1.98 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a single-bond geometry to one Hg(1) and one Hg(2) atom. In the second Si site, Si(2) is bonded in a single-bond geometry to one Hg(2) atom.