data_HfHgCl2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.0
_cell_length_b   5.0
_cell_length_c   5.0
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfHgCl2
_chemical_formula_sum   'Hf1 Hg1 Cl2'
_cell_volume   88.25
_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
  Hf  Hf2  1  0.53  0.53  0.53  1.0
  Hg  Hg3  1  0.3  0.3  0.3  1.0
  Cl  Cl0  1  0.0  0.0  0.0  1.0
  Cl  Cl1  1  0.77  0.77  0.77  1.0

data_HfHgCl2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.0
_cell_length_b   5.0
_cell_length_c   12.24
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   HfHgCl2
_chemical_formula_sum   'Hf3 Hg3 Cl6'
_cell_volume   264.75
_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
  Hf  Hf0  3  0.0  0.0  0.47  1.0
  Hg  Hg1  3  0.0  0.0  0.7  1.0
  Cl  Cl2  3  0.0  0.0  0.0  1.0
  Cl  Cl3  3  0.0  0.0  0.23  1.0

Hf Hg Cl Cl
HfHgCl2 crystallizes in the trigonal R3m space group. Hf(1) is bonded in a 11-coordinate geometry to four equivalent Hg(1), three equivalent Cl(1), and four equivalent Cl(2) atoms. There is one shorter (2.85 Å) and three longer (3.14 Å) Hf(1)-Hg(1) bond lengths. All Hf(1)-Cl(1) bond lengths are 3.31 Å. There is one shorter (2.85 Å) and three longer (3.14 Å) Hf(1)-Cl(2) bond lengths. Hg(1) is bonded to four equivalent Hf(1) and three equivalent Cl(1) atoms to form distorted HgHf4Cl3 hexagonal pyramids that share corners with six equivalent Hg(1)Hf4Cl3 hexagonal pyramids, corners with four equivalent Cl(2)Hf4 tetrahedra, edges with six equivalent Hg(1)Hf4Cl3 hexagonal pyramids, and edges with six equivalent Cl(2)Hf4 tetrahedra. All Hg(1)-Cl(1) bond lengths are 2.91 Å. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 6-coordinate geometry to three equivalent Hf(1) and three equivalent Hg(1) atoms. In the second Cl site, Cl(2) is bonded to four equivalent Hf(1) atoms to form ClHf4 tetrahedra that share corners with four equivalent Hg(1)Hf4Cl3 hexagonal pyramids, corners with twelve equivalent Cl(2)Hf4 tetrahedra, and edges with six equivalent Hg(1)Hf4Cl3 hexagonal pyramids.