data_HgSb2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.2
_cell_length_b   5.2
_cell_length_c   5.2
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HgSb2As
_chemical_formula_sum   'Hg1 Sb2 As1'
_cell_volume   99.6
_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  Hg1  1  0.84  0.84  0.84  1.0
  Sb  Sb2  1  0.68  0.68  0.68  1.0
  Sb  Sb3  1  0.52  0.52  0.52  1.0
  As  As0  1  0.0  0.0  0.0  1.0

data_HgSb2As
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.2
_cell_length_b   5.2
_cell_length_c   12.74
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   HgSb2As
_chemical_formula_sum   'Hg3 Sb6 As3'
_cell_volume   298.8
_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  0.16  1.0
  Sb  Sb1  3  0.0  0.0  0.32  1.0
  Sb  Sb2  3  0.0  0.0  0.48  1.0
  As  As3  3  0.0  0.0  1.0  1.0

Hg Sb Sb As
Hg Sb Sb As 0 1 o o o 0 3 + + + 1 2 o o o 
HgSb2As crystallizes in the trigonal R3m space group. Hg(1) is bonded in a distorted linear geometry to one Sb(1), three equivalent Sb(2), and one As(1) atom. The Hg(1)-Sb(1) bond length is 2.04 Å. All Hg(1)-Sb(2) bond lengths are 3.01 Å. The Hg(1)-As(1) bond length is 2.04 Å. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one Hg(1), one Sb(2), and three equivalent As(1) atoms to form distorted SbHgSbAs3 trigonal bipyramids that share corners with six equivalent Sb(1)HgSbAs3 trigonal bipyramids,  a cornercorner with one As(1)HgSb3 trigonal pyramid, and corners with three equivalent Sb(2)Hg3Sb trigonal pyramids. The Sb(1)-Sb(2) bond length is 2.04 Å. All Sb(1)-As(1) bond lengths are 3.01 Å. In the second Sb site, Sb(2) is bonded to three equivalent Hg(1) and one Sb(1) atom to form SbHg3Sb trigonal pyramids that share corners with three equivalent Sb(1)HgSbAs3 trigonal bipyramids, corners with six equivalent Sb(2)Hg3Sb trigonal pyramids, and edges with three equivalent As(1)HgSb3 trigonal pyramids. As(1) is bonded to one Hg(1) and three equivalent Sb(1) atoms to form distorted AsHgSb3 trigonal pyramids that share  a cornercorner with one Sb(1)HgSbAs3 trigonal bipyramid, corners with six equivalent As(1)HgSb3 trigonal pyramids, and edges with three equivalent Sb(2)Hg3Sb trigonal pyramids.