data_HfHgAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.61
_cell_length_b   4.61
_cell_length_c   4.61
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfHgAs
_chemical_formula_sum   'Hf1 Hg1 As1'
_cell_volume   69.44
_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  Hf1  1  0.89  0.89  0.89  1.0
  Hg  Hg2  1  0.63  0.63  0.63  1.0
  As  As0  1  0.0  0.0  0.0  1.0

data_HfHgAs
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.61
_cell_length_b   4.61
_cell_length_c   11.3
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   HfHgAs
_chemical_formula_sum   'Hf3 Hg3 As3'
_cell_volume   208.33
_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  0.11  1.0
  Hg  Hg1  3  0.0  0.0  0.37  1.0
  As  As2  3  0.0  0.0  0.0  1.0

Hf Hg As
Hf Hg As 0 2 + + + 0 1 + o o 0 1 o + o 0 1 o o + 0 1 o o o 1 2 o + + 1 2 + o + 1 2 + + o 
HfHgAs crystallizes in the trigonal R3m space group. Hf(1) is bonded in a single-bond geometry to four equivalent Hg(1) and one As(1) atom. There are three shorter (2.78 Å) and one longer (2.97 Å) Hf(1)-Hg(1) bond length. The Hf(1)-As(1) bond length is 1.20 Å. Hg(1) is bonded to four equivalent Hf(1) and three equivalent As(1) atoms to form a mixture of distorted corner and edge-sharing HgHf4As3 hexagonal pyramids. All Hg(1)-As(1) bond lengths are 2.69 Å. As(1) is bonded in a single-bond geometry to one Hf(1) and three equivalent Hg(1) atoms.