data_SiNiHg4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.72
_cell_length_b   5.72
_cell_length_c   5.72
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SiNiHg4
_chemical_formula_sum   'Si1 Ni1 Hg4'
_cell_volume   132.25
_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  Si5  1  0.0  0.0  0.0  1.0
  Ni  Ni4  1  0.07  0.07  0.07  1.0
  Hg  Hg0  1  0.05  0.05  0.03  1.0
  Hg  Hg1  1  0.05  0.03  0.05  1.0
  Hg  Hg2  1  0.03  0.05  0.05  1.0
  Hg  Hg3  1  0.03  0.03  0.03  1.0

data_SiNiHg4
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.72
_cell_length_b   5.72
_cell_length_c   14.01
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SiNiHg4
_chemical_formula_sum   'Si3 Ni3 Hg12'
_cell_volume   396.76
_cell_formula_units_Z   3
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  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+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  3  0.0  0.0  0.0  1.0
  Ni  Ni1  3  0.0  0.0  0.93  1.0
  Hg  Hg2  9  0.01  0.01  0.95  1.0
  Hg  Hg3  3  0.0  0.0  0.97  1.0

Si Ni Hg Hg Hg Hg
NiHg4Si is Copper structured and crystallizes in the trigonal R3m space group. The structure is zero-dimensional and consists of three NiHg4Si clusters. Ni(1) is bonded in a 3-coordinate geometry to three equivalent Hg(1) atoms. All Ni(1)-Hg(1) bond lengths are 0.27 Å. There are two inequivalent Hg sites. In the first Hg site, Hg(2) is bonded in a distorted single-bond geometry to three equivalent Hg(1) and one Si(1) atom. All Hg(2)-Hg(1) bond lengths are 0.19 Å. The Hg(2)-Si(1) bond length is 0.48 Å. In the second Hg site, Hg(1) is bonded in a 3-coordinate geometry to one Ni(1), one Hg(2), and two equivalent Hg(1) atoms. Both Hg(1)-Hg(1) bond lengths are 0.11 Å. Si(1) is bonded in a single-bond geometry to one Hg(2) atom.