data_MgTe2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.21
_cell_length_b   5.21
_cell_length_c   5.21
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgTe2Se
_chemical_formula_sum   'Mg1 Te2 Se1'
_cell_volume   100.21
_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  Mg0  1  0.0  0.0  0.0  1.0
  Te  Te2  1  0.69  0.69  0.69  1.0
  Te  Te3  1  0.53  0.53  0.53  1.0
  Se  Se1  1  0.84  0.84  0.84  1.0

data_MgTe2Se
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.21
_cell_length_b   5.21
_cell_length_c   12.77
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MgTe2Se
_chemical_formula_sum   'Mg3 Te6 Se3'
_cell_volume   300.62
_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
  Te  Te1  3  0.0  0.0  0.31  1.0
  Te  Te2  3  0.0  0.0  0.47  1.0
  Se  Se3  3  0.0  0.0  0.16  1.0

Mg Te Te Se
MgTe2Se crystallizes in the trigonal R3m space group. Mg(1) is bonded in a distorted single-bond geometry to three equivalent Te(1) and one Se(1) atom. All Mg(1)-Te(1) bond lengths are 3.02 Å. The Mg(1)-Se(1) bond length is 2.00 Å. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded to three equivalent Mg(1), one Te(2), and one Se(1) atom to form distorted TeMg3TeSe trigonal bipyramids that share corners with six equivalent Te(1)Mg3TeSe trigonal bipyramids and corners with three equivalent Te(2)TeSe3 trigonal pyramids. The Te(1)-Te(2) bond length is 2.00 Å. The Te(1)-Se(1) bond length is 2.00 Å. In the second Te site, Te(2) is bonded to one Te(1) and three equivalent Se(1) atoms to form TeTeSe3 trigonal pyramids that share corners with three equivalent Te(1)Mg3TeSe trigonal bipyramids and corners with six equivalent Te(2)TeSe3 trigonal pyramids. All Te(2)-Se(1) bond lengths are 3.02 Å. Se(1) is bonded in a distorted linear geometry to one Mg(1), one Te(1), and three equivalent Te(2) atoms.