data_Zn2HgSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.88
_cell_length_b   4.88
_cell_length_c   4.88
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Zn2HgSe
_chemical_formula_sum   'Zn2 Hg1 Se1'
_cell_volume   82.39
_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
  Zn  Zn2  1  0.18  0.18  0.18  1.0
  Zn  Zn3  1  0.73  0.73  0.73  1.0
  Hg  Hg0  1  0.45  0.45  0.45  1.0
  Se  Se1  1  0.0  0.0  0.0  1.0

data_Zn2HgSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.88
_cell_length_b   4.88
_cell_length_c   11.96
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Zn2HgSe
_chemical_formula_sum   'Zn6 Hg3 Se3'
_cell_volume   247.17
_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
  Zn  Zn0  3  0.0  0.0  0.27  1.0
  Zn  Zn1  3  0.0  0.0  0.82  1.0
  Hg  Hg2  3  0.0  0.0  0.55  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Zn Zn Hg Se
Zn Zn Hg Se 0 3 o o o 0 1 o - - 0 1 - o - 0 1 - - o 0 2 o o o 0 2 o o - 0 2 o - o 0 2 - o o 1 2 o o o 1 2 o o + 1 2 o + o 1 2 + o o 1 3 o + + 1 3 + o + 1 3 + + o 1 3 + + + 2 3 o o + 2 3 o + o 2 3 + o o 
HgZn2Se is Heusler structured and crystallizes in the trigonal R3m space group. Hg(1) is bonded in a 11-coordinate geometry to four equivalent Zn(1), four equivalent Zn(2), and three equivalent Se(1) atoms. There are three shorter (2.91 Å) and one longer (3.27 Å) Hg(1)-Zn(1) bond length. There are three shorter (2.91 Å) and one longer (3.27 Å) Hg(1)-Zn(2) bond length. All Hg(1)-Se(1) bond lengths are 3.17 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted single-bond geometry to four equivalent Hg(1) and one Se(1) atom. The Zn(1)-Se(1) bond length is 2.16 Å. In the second Zn site, Zn(2) is bonded in a 6-coordinate geometry to four equivalent Hg(1) and three equivalent Se(1) atoms. All Zn(2)-Se(1) bond lengths are 2.91 Å. Se(1) is bonded in a distorted single-bond geometry to three equivalent Hg(1), one Zn(1), and three equivalent Zn(2) atoms.