data_TlSiHg2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   5.18
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   TlSiHg2
_chemical_formula_sum   'Tl1 Si1 Hg2'
_cell_volume   98.17
_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
  Tl  Tl3  1  0.66  0.66  0.66  1.0
  Si  Si2  1  0.0  0.0  0.0  1.0
  Hg  Hg0  1  0.83  0.83  0.83  1.0
  Hg  Hg1  1  0.49  0.49  0.49  1.0

data_TlSiHg2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   12.68
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   TlSiHg2
_chemical_formula_sum   'Tl3 Si3 Hg6'
_cell_volume   294.51
_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
  Tl  Tl0  3  0.0  0.0  0.34  1.0
  Si  Si1  3  0.0  0.0  0.0  1.0
  Hg  Hg2  3  0.0  0.0  0.17  1.0
  Hg  Hg3  3  0.0  0.0  0.51  1.0

Tl Si Hg Hg
Tl Si Hg Hg 0 3 o o o 0 2 o o o 1 2 - - - 
Hg2TlSi crystallizes in the trigonal R3m space group. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a distorted linear geometry to one Tl(1) and one Si(1) atom. The Hg(1)-Tl(1) bond length is 2.15 Å. The Hg(1)-Si(1) bond length is 2.15 Å. In the second Hg site, Hg(2) is bonded in a single-bond geometry to one Tl(1) atom. The Hg(2)-Tl(1) bond length is 2.15 Å. Tl(1) is bonded to one Hg(1), one Hg(2), and three equivalent Si(1) atoms to form distorted TlSi3Hg2 trigonal bipyramids that share corners with six equivalent Tl(1)Si3Hg2 trigonal bipyramids and  a cornercorner with one Si(1)Tl3Hg trigonal pyramid. All Tl(1)-Si(1) bond lengths are 2.99 Å. Si(1) is bonded to one Hg(1) and three equivalent Tl(1) atoms to form SiTl3Hg trigonal pyramids that share  a cornercorner with one Tl(1)Si3Hg2 trigonal bipyramid and corners with six equivalent Si(1)Tl3Hg trigonal pyramids.