data_Tc2C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.97
_cell_length_b   4.97
_cell_length_c   4.97
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Tc2C
_chemical_formula_sum   'Tc4 C2'
_cell_volume   87.05
_cell_formula_units_Z   2
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  Tc2  1  0.64  0.64  0.4  1.0
  Tc  Tc3  1  0.4  0.64  0.64  1.0
  Tc  Tc4  1  0.64  0.4  0.64  1.0
  Tc  Tc5  1  0.4  0.4  0.4  1.0
  C  C0  1  0.0  0.0  0.0  1.0
  C  C1  1  0.76  0.76  0.76  1.0

data_Tc2C
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.97
_cell_length_b   4.97
_cell_length_c   12.19
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Tc2C
_chemical_formula_sum   'Tc12 C6'
_cell_volume   261.16
_cell_formula_units_Z   6
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  9  0.16  0.08  0.44  1.0
  Tc  Tc1  3  0.0  0.0  0.6  1.0
  C  C2  3  0.0  0.0  0.0  1.0
  C  C3  3  0.0  0.0  0.24  1.0

Tc Tc Tc Tc C C
Tc2C crystallizes in the trigonal R3m space group. There are two inequivalent Tc sites. In the first Tc site, Tc(1) is bonded in a 6-coordinate geometry to one Tc(2), two equivalent Tc(1), one C(1), and two equivalent C(2) atoms. The Tc(1)-Tc(2) bond length is 2.08 Å. Both Tc(1)-Tc(1) bond lengths are 1.20 Å. The Tc(1)-C(1) bond length is 2.55 Å. There is one shorter (2.55 Å) and one longer (2.71 Å) Tc(1)-C(2) bond length. In the second Tc site, Tc(2) is bonded in a 9-coordinate geometry to three equivalent Tc(1), three equivalent C(1), and three equivalent C(2) atoms. All Tc(2)-C(1) bond lengths are 2.98 Å. All Tc(2)-C(2) bond lengths are 2.89 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a 3-coordinate geometry to three equivalent Tc(1) and three equivalent Tc(2) atoms. In the second C site, C(2) is bonded in a 9-coordinate geometry to three equivalent Tc(2) and six equivalent Tc(1) atoms.