data_MgHgTeSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.17
_cell_length_b   5.17
_cell_length_c   5.17
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgHgTeSe
_chemical_formula_sum   'Mg1 Hg1 Te1 Se1'
_cell_volume   97.93
_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
  Mg  Mg1  1  0.0  0.0  0.0  1.0
  Hg  Hg0  1  0.66  0.66  0.66  1.0
  Te  Te3  1  0.83  0.83  0.83  1.0
  Se  Se2  1  0.49  0.49  0.49  1.0

data_MgHgTeSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.17
_cell_length_b   5.17
_cell_length_c   12.67
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MgHgTeSe
_chemical_formula_sum   'Mg3 Hg3 Te3 Se3'
_cell_volume   293.79
_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
  Mg  Mg0  3  0.0  0.0  0.0  1.0
  Hg  Hg1  3  0.0  0.0  0.34  1.0
  Te  Te2  3  0.0  0.0  0.17  1.0
  Se  Se3  3  0.0  0.0  0.51  1.0

Mg Hg Te Se
MgHgTeSe crystallizes in the trigonal R3m space group. Mg(1) is bonded to three equivalent Hg(1) and one Te(1) atom to form distorted MgHg3Te trigonal pyramids that share  a cornercorner with one Hg(1)Mg3TeSe trigonal bipyramid, corners with three equivalent Te(1)MgHgSe3 trigonal bipyramids, corners with six equivalent Mg(1)Hg3Te trigonal pyramids, and edges with three equivalent Se(1)HgTe3 trigonal pyramids. All Mg(1)-Hg(1) bond lengths are 2.99 Å. The Mg(1)-Te(1) bond length is 2.16 Å. Hg(1) is bonded to three equivalent Mg(1), one Te(1), and one Se(1) atom to form HgMg3TeSe trigonal bipyramids that share corners with six equivalent Hg(1)Mg3TeSe trigonal bipyramids,  a cornercorner with one Mg(1)Hg3Te trigonal pyramid, corners with three equivalent Se(1)HgTe3 trigonal pyramids, and edges with three equivalent Te(1)MgHgSe3 trigonal bipyramids. The Hg(1)-Te(1) bond length is 2.16 Å. The Hg(1)-Se(1) bond length is 2.16 Å. Te(1) is bonded to one Mg(1), one Hg(1), and three equivalent Se(1) atoms to form distorted TeMgHgSe3 trigonal bipyramids that share corners with six equivalent Te(1)MgHgSe3 trigonal bipyramids,  a cornercorner with one Se(1)HgTe3 trigonal pyramid, corners with three equivalent Mg(1)Hg3Te trigonal pyramids, and edges with three equivalent Hg(1)Mg3TeSe trigonal bipyramids. All Te(1)-Se(1) bond lengths are 2.99 Å. Se(1) is bonded to one Hg(1) and three equivalent Te(1) atoms to form distorted SeHgTe3 trigonal pyramids that share  a cornercorner with one Te(1)MgHgSe3 trigonal bipyramid, corners with three equivalent Hg(1)Mg3TeSe trigonal bipyramids, corners with six equivalent Se(1)HgTe3 trigonal pyramids, and edges with three equivalent Mg(1)Hg3Te trigonal pyramids.