data_NbHgCl2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.98
_cell_length_b   4.98
_cell_length_c   4.98
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NbHgCl2
_chemical_formula_sum   'Nb1 Hg1 Cl2'
_cell_volume   87.54
_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
  Nb  Nb3  1  0.52  0.52  0.52  1.0
  Hg  Hg2  1  0.29  0.29  0.29  1.0
  Cl  Cl0  1  0.76  0.76  0.76  1.0
  Cl  Cl1  1  0.0  0.0  0.0  1.0

data_NbHgCl2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.98
_cell_length_b   4.98
_cell_length_c   12.21
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NbHgCl2
_chemical_formula_sum   'Nb3 Hg3 Cl6'
_cell_volume   262.62
_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
  Nb  Nb0  3  0.0  0.0  0.48  1.0
  Hg  Hg1  3  0.0  0.0  0.71  1.0
  Cl  Cl2  3  0.0  0.0  -0.0  1.0
  Cl  Cl3  3  0.0  0.0  0.24  1.0

Nb Hg Cl Cl
NbHgCl2 crystallizes in the trigonal R3m space group. Nb(1) is bonded in a 11-coordinate geometry to four equivalent Hg(1), three equivalent Cl(2), and four equivalent Cl(1) atoms. There is one shorter (2.90 Å) and three longer (3.10 Å) Nb(1)-Hg(1) bond lengths. All Nb(1)-Cl(2) bond lengths are 3.36 Å. There is one shorter (2.90 Å) and three longer (3.10 Å) Nb(1)-Cl(1) bond lengths. Hg(1) is bonded in a 7-coordinate geometry to four equivalent Nb(1) and three equivalent Cl(2) atoms. All Hg(1)-Cl(2) bond lengths are 2.93 Å. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to four equivalent Nb(1) atoms to form corner-sharing ClNb4 tetrahedra. In the second Cl site, Cl(2) is bonded in a distorted trigonal planar geometry to three equivalent Nb(1) and three equivalent Hg(1) atoms.