data_HgAsCl2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.99
_cell_length_b   4.99
_cell_length_c   4.99
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HgAsCl2
_chemical_formula_sum   'Hg1 As1 Cl2'
_cell_volume   88.02
_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
  Hg  Hg3  1  0.3  0.3  0.3  1.0
  As  As0  1  0.53  0.53  0.53  1.0
  Cl  Cl1  1  0.0  0.0  0.0  1.0
  Cl  Cl2  1  0.77  0.77  0.77  1.0

data_HgAsCl2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.99
_cell_length_b   4.99
_cell_length_c   12.23
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   HgAsCl2
_chemical_formula_sum   'Hg3 As3 Cl6'
_cell_volume   264.05
_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
  Hg  Hg0  3  0.0  0.0  0.7  1.0
  As  As1  3  0.0  0.0  0.47  1.0
  Cl  Cl2  3  0.0  0.0  0.0  1.0
  Cl  Cl3  3  0.0  0.0  0.23  1.0

Hg As Cl Cl
Hg As Cl Cl 0 1 o - o 0 1 - o o 0 1 o o - 0 1 o o o 0 2 o o + 0 2 o + o 0 2 + o o 0 3 - o o 0 3 o - o 0 3 o o - 1 3 o - o 1 3 - o o 1 3 o o - 1 3 o o o 1 2 o + + 1 2 + o + 1 2 + + o 2 3 - - - 2 3 - - o 2 3 o - - 2 3 - o - 
HgAsCl2 crystallizes in the trigonal R3m space group. Hg(1) is bonded in a 7-coordinate geometry to four equivalent As(1) and three equivalent Cl(1) atoms. There is one shorter (2.87 Å) and three longer (3.12 Å) Hg(1)-As(1) bond lengths. All Hg(1)-Cl(1) bond lengths are 2.92 Å. As(1) is bonded in a 5-coordinate geometry to four equivalent Hg(1) and one Cl(2) atom. The As(1)-Cl(2) bond length is 2.87 Å. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a trigonal planar geometry to three equivalent Hg(1) atoms. In the second Cl site, Cl(2) is bonded in a single-bond geometry to one As(1) atom.