data_Ta2CoTc
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.44
_cell_length_b   4.44
_cell_length_c   4.44
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2CoTc
_chemical_formula_sum   'Ta2 Co1 Tc1'
_cell_volume   61.97
_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
  Ta  Ta1  1  0.57  0.57  0.57  1.0
  Ta  Ta2  1  0.71  0.71  0.71  1.0
  Co  Co0  1  0.0  0.0  0.0  1.0
  Tc  Tc3  1  0.14  0.14  0.14  1.0

data_Ta2CoTc
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.44
_cell_length_b   4.44
_cell_length_c   10.88
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Ta2CoTc
_chemical_formula_sum   'Ta6 Co3 Tc3'
_cell_volume   185.9
_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
  Ta  Ta0  3  0.0  0.0  0.29  1.0
  Ta  Ta1  3  0.0  0.0  0.43  1.0
  Co  Co2  3  0.0  0.0  0.0  1.0
  Tc  Tc3  3  0.0  0.0  0.86  1.0

Ta Ta Co Tc
Ta2TcCo crystallizes in the trigonal R3m space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to one Ta(2), three equivalent Tc(1), and three equivalent Co(1) atoms. The Ta(1)-Ta(2) bond length is 1.53 Å. All Ta(1)-Tc(1) bond lengths are 2.77 Å. All Ta(1)-Co(1) bond lengths are 2.77 Å. In the second Ta site, Ta(2) is bonded in a 1-coordinate geometry to one Ta(1) atom. Tc(1) is bonded in a 1-coordinate geometry to three equivalent Ta(1) and one Co(1) atom. The Tc(1)-Co(1) bond length is 1.53 Å. Co(1) is bonded in a distorted single-bond geometry to three equivalent Ta(1) and one Tc(1) atom.