data_Tl2TcSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   5.18
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Tl2TcSe
_chemical_formula_sum   'Tl2 Tc1 Se1'
_cell_volume   98.54
_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
  Tl  Tl2  1  0.83  0.83  0.83  1.0
  Tl  Tl3  1  0.5  0.5  0.5  1.0
  Tc  Tc1  1  0.67  0.67  0.67  1.0
  Se  Se0  1  0.0  0.0  0.0  1.0

data_Tl2TcSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   12.7
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Tl2TcSe
_chemical_formula_sum   'Tl6 Tc3 Se3'
_cell_volume   295.63
_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
  Tl  Tl0  3  0.0  0.0  0.17  1.0
  Tl  Tl1  3  0.0  0.0  0.5  1.0
  Tc  Tc2  3  0.0  0.0  0.33  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Tl Tl Tc Se
Tl Tl Tc Se 0 2 o o o 0 3 + + + 1 2 o o o 
TcTl2Se crystallizes in the trigonal R3m space group. Tc(1) is bonded to one Tl(1), one Tl(2), and three equivalent Se(1) atoms to form distorted TcTl2Se3 trigonal bipyramids that share corners with six equivalent Tc(1)Tl2Se3 trigonal bipyramids and  a cornercorner with one Se(1)TlTc3 trigonal pyramid. The Tc(1)-Tl(1) bond length is 2.12 Å. The Tc(1)-Tl(2) bond length is 2.12 Å. All Tc(1)-Se(1) bond lengths are 2.99 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a linear geometry to one Tc(1) and one Se(1) atom. The Tl(1)-Se(1) bond length is 2.12 Å. In the second Tl site, Tl(2) is bonded in a single-bond geometry to one Tc(1) atom. Se(1) is bonded to three equivalent Tc(1) and one Tl(1) atom to form distorted SeTlTc3 trigonal pyramids that share  a cornercorner with one Tc(1)Tl2Se3 trigonal bipyramid and corners with six equivalent Se(1)TlTc3 trigonal pyramids.