data_Si2NiHg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.32
_cell_length_b   5.32
_cell_length_c   3.35
_cell_angle_alpha   108.22
_cell_angle_beta   108.22
_cell_angle_gamma   120.47
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2NiHg
_chemical_formula_sum   'Si2 Ni1 Hg1'
_cell_volume   63.48
_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
  Si  Si2  1  0.32  0.69  0.0  1.0
  Si  Si3  1  0.32  0.31  0.0  1.0
  Ni  Ni1  1  0.0  0.0  0.0  1.0
  Hg  Hg0  1  0.64  0.0  0.0  1.0

data_Si2NiHg
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.35
_cell_length_b   4.1
_cell_length_c   5.32
_cell_angle_alpha   112.54
_cell_angle_beta   108.22
_cell_angle_gamma   90.43
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2NiHg
_chemical_formula_sum   'Si2 Ni1 Hg1'
_cell_volume   63.48
_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
  Si  Si0  1  0.31  0.31  0.63  1.0
  Si  Si1  1  0.69  0.69  0.01  1.0
  Ni  Ni2  1  0.0  0.0  0.0  1.0
  Hg  Hg3  1  0.0  0.0  0.64  1.0

Si Si Ni Hg
Si Si Ni Hg 0 3 o + o 1 2 o o o 2 3 - o o 
NiHgSi2 is Indium-like structured and crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one NiHgSi2 cluster. Ni(1) is bonded in a distorted bent 120 degrees geometry to one Hg(1) and one Si(2) atom. The Ni(1)-Hg(1) bond length is 1.92 Å. The Ni(1)-Si(2) bond length is 1.66 Å. Hg(1) is bonded in a distorted bent 120 degrees geometry to one Ni(1) and one Si(1) atom. The Hg(1)-Si(1) bond length is 1.66 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted single-bond geometry to one Hg(1) atom. In the second Si site, Si(2) is bonded in a 1-coordinate geometry to one Ni(1) atom.