data_TcAs3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.15
_cell_length_b   5.15
_cell_length_c   5.15
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   TcAs3
_chemical_formula_sum   'Tc2 As6'
_cell_volume   136.51
_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  Tc6  1  0.57  0.57  0.57  1.0
  Tc  Tc7  1  0.0  0.0  0.0  1.0
  As  As0  1  0.29  0.0  0.57  1.0
  As  As1  1  0.86  0.0  0.57  1.0
  As  As2  1  0.57  0.29  0.0  1.0
  As  As3  1  0.57  0.86  0.0  1.0
  As  As4  1  0.0  0.57  0.86  1.0
  As  As5  1  0.0  0.57  0.29  1.0

data_TcAs3
_symmetry_space_group_name_H-M   R3
_cell_length_a   7.28
_cell_length_b   7.28
_cell_length_c   8.92
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   146
_chemical_formula_structural   TcAs3
_chemical_formula_sum   'Tc6 As18'
_cell_volume   409.52
_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  'x+1/3, y+2/3, z+2/3'
  5  '-y+1/3, x-y+2/3, z+2/3'
  6  '-x+y+1/3, -x+2/3, z+2/3'
  7  'x+2/3, y+1/3, z+1/3'
  8  '-y+2/3, x-y+1/3, z+1/3'
  9  '-x+y+2/3, -x+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  0.0  1.0
  Tc  Tc1  3  0.0  0.0  0.57  1.0
  As  As2  9  -0.0  0.71  0.29  1.0
  As  As3  9  0.05  0.24  0.81  1.0

Tc Tc As As As As As As
TcAs3 crystallizes in the trigonal R3 space group. There are two inequivalent Tc sites. In the first Tc site, Tc(1) is bonded in a 6-coordinate geometry to three equivalent As(1) and three equivalent As(2) atoms. All Tc(1)-As(1) bond lengths are 2.64 Å. All Tc(1)-As(2) bond lengths are 2.64 Å. In the second Tc site, Tc(2) is bonded in a 3-coordinate geometry to three equivalent As(1) and three equivalent As(2) atoms. All Tc(2)-As(1) bond lengths are 2.64 Å. All Tc(2)-As(2) bond lengths are 2.30 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 3-coordinate geometry to one Tc(1), one Tc(2), and one As(2) atom. The As(1)-As(2) bond length is 2.19 Å. In the second As site, As(2) is bonded in a 3-coordinate geometry to one Tc(1), one Tc(2), and one As(1) atom.