data_TcPb2Se
_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   TcPb2Se
_chemical_formula_sum   'Tc1 Pb2 Se1'
_cell_volume   98.19
_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
  Tc  Tc3  1  0.66  0.66  0.66  1.0
  Pb  Pb0  1  0.49  0.49  0.49  1.0
  Pb  Pb1  1  0.83  0.83  0.83  1.0
  Se  Se2  1  0.0  0.0  0.0  1.0

data_TcPb2Se
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   12.68
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   TcPb2Se
_chemical_formula_sum   'Tc3 Pb6 Se3'
_cell_volume   294.58
_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
  Tc  Tc0  3  0.0  0.0  0.34  1.0
  Pb  Pb1  3  0.0  0.0  0.17  1.0
  Pb  Pb2  3  0.0  0.0  0.51  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Tc Pb Pb Se
TcPb2Se crystallizes in the trigonal R3m space group. Tc(1) is bonded to one Pb(1), one Pb(2), and three equivalent Se(1) atoms to form distorted TcPb2Se3 trigonal bipyramids that share corners with six equivalent Tc(1)Pb2Se3 trigonal bipyramids and  a cornercorner with one Se(1)Tc3Pb trigonal pyramid. The Tc(1)-Pb(1) bond length is 2.15 Å. The Tc(1)-Pb(2) bond length is 2.15 Å. All Tc(1)-Se(1) bond lengths are 2.99 Å. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a single-bond geometry to one Tc(1) atom. In the second Pb site, Pb(2) is bonded in a distorted linear geometry to one Tc(1) and one Se(1) atom. The Pb(2)-Se(1) bond length is 2.15 Å. Se(1) is bonded to three equivalent Tc(1) and one Pb(2) atom to form SeTc3Pb trigonal pyramids that share  a cornercorner with one Tc(1)Pb2Se3 trigonal bipyramid and corners with six equivalent Se(1)Tc3Pb trigonal pyramids.