data_GaHg2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.05
_cell_length_b   5.05
_cell_length_c   5.05
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   GaHg2As
_chemical_formula_sum   'Ga1 Hg2 As1'
_cell_volume   90.98
_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
  Ga  Ga1  1  0.0  0.0  0.0  1.0
  Hg  Hg2  1  0.35  0.35  0.35  1.0
  Hg  Hg3  1  0.78  0.78  0.78  1.0
  As  As0  1  0.57  0.57  0.57  1.0

data_GaHg2As
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.05
_cell_length_b   5.05
_cell_length_c   12.37
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   GaHg2As
_chemical_formula_sum   'Ga3 Hg6 As3'
_cell_volume   272.94
_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
  Ga  Ga0  3  0.0  0.0  0.0  1.0
  Hg  Hg1  3  0.0  0.0  0.22  1.0
  Hg  Hg2  3  0.0  0.0  0.65  1.0
  As  As3  3  0.0  0.0  0.43  1.0

Ga Hg Hg As
Ga Hg Hg As 0 2 - - - 0 2 - - o 0 2 o - - 0 2 - o - 0 3 - - o 0 3 - o - 0 3 o - - 0 1 - o o 0 1 o - o 0 1 o o - 1 3 o - o 1 3 - o o 1 3 o o - 1 3 o o o 1 2 - o o 1 2 o - o 1 2 o o - 2 3 o o o 2 3 o o + 2 3 + o o 2 3 o + o 
Hg2GaAs is Heusler structured and crystallizes in the trigonal R3m space group. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to three equivalent Ga(1) and one As(1) atom to form distorted corner-sharing HgGa3As trigonal pyramids. All Hg(1)-Ga(1) bond lengths are 2.93 Å. The Hg(1)-As(1) bond length is 2.66 Å. In the second Hg site, Hg(2) is bonded in a linear geometry to one Ga(1) and one As(1) atom. The Hg(2)-Ga(1) bond length is 2.66 Å. The Hg(2)-As(1) bond length is 2.66 Å. Ga(1) is bonded to one Hg(2) and three equivalent Hg(1) atoms to form distorted corner-sharing GaHg4 trigonal pyramids. As(1) is bonded in a linear geometry to one Hg(1) and one Hg(2) atom.