data_MnHg2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.03
_cell_length_b   5.03
_cell_length_c   5.03
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MnHg2Se
_chemical_formula_sum   'Mn1 Hg2 Se1'
_cell_volume   90.22
_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
  Mn  Mn2  1  0.0  0.0  0.0  1.0
  Hg  Hg0  1  0.56  0.56  0.56  1.0
  Hg  Hg1  1  0.78  0.78  0.78  1.0
  Se  Se3  1  0.34  0.34  0.34  1.0

data_MnHg2Se
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.03
_cell_length_b   5.03
_cell_length_c   12.33
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MnHg2Se
_chemical_formula_sum   'Mn3 Hg6 Se3'
_cell_volume   270.66
_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
  Mn  Mn0  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  0.44  1.0
  Se  Se3  3  0.0  0.0  0.66  1.0

Mn Hg Hg Se
MnHg2Se crystallizes in the trigonal R3m space group. Mn(1) is bonded to three equivalent Hg(1), four equivalent Hg(2), and three equivalent Se(1) atoms to form distorted MnHg7Se3 trigonal pyramids that share corners with three equivalent Se(1)Mn3Hg trigonal pyramids, corners with six equivalent Mn(1)Hg7Se3 trigonal pyramids, and faces with six equivalent Mn(1)Hg7Se3 trigonal pyramids. All Mn(1)-Hg(1) bond lengths are 3.19 Å. There is one shorter (2.71 Å) and three longer (3.22 Å) Mn(1)-Hg(2) bond lengths. All Mn(1)-Se(1) bond lengths are 2.91 Å. There are two inequivalent Hg sites. In the first Hg site, Hg(1) is bonded in a distorted single-bond geometry to three equivalent Mn(1) and one Se(1) atom. The Hg(1)-Se(1) bond length is 2.71 Å. In the second Hg site, Hg(2) is bonded in a distorted single-bond geometry to four equivalent Mn(1) atoms. Se(1) is bonded to three equivalent Mn(1) and one Hg(1) atom to form distorted SeMn3Hg trigonal pyramids that share corners with three equivalent Mn(1)Hg7Se3 trigonal pyramids and corners with six equivalent Se(1)Mn3Hg trigonal pyramids.