data_Ta3Nb5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.62
_cell_length_b   6.62
_cell_length_c   6.62
_cell_angle_alpha   90.01
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta3Nb5
_chemical_formula_sum   'Ta6 Nb10'
_cell_volume   290.49
_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
  Ta  Ta10  1  0.31  0.0  0.01  1.0
  Ta  Ta11  1  0.31  0.66  0.34  1.0
  Ta  Ta12  1  0.65  0.0  0.02  1.0
  Ta  Ta13  1  0.97  0.0  0.02  1.0
  Ta  Ta14  1  0.31  0.34  0.34  1.0
  Ta  Ta15  1  0.0  0.0  0.68  1.0
  Nb  Nb0  1  0.0  0.0  0.01  1.0
  Nb  Nb1  1  0.0  0.67  0.34  1.0
  Nb  Nb2  1  0.65  0.34  0.68  1.0
  Nb  Nb3  1  0.97  0.34  0.68  1.0
  Nb  Nb4  1  0.0  0.33  0.34  1.0
  Nb  Nb5  1  0.31  0.0  0.68  1.0
  Nb  Nb6  1  0.65  0.0  0.34  1.0
  Nb  Nb7  1  0.97  0.0  0.34  1.0
  Nb  Nb8  1  0.65  0.66  0.68  1.0
  Nb  Nb9  1  0.97  0.66  0.68  1.0

data_Ta3Nb5
_symmetry_space_group_name_H-M   Pm
_cell_length_a   6.62
_cell_length_b   6.62
_cell_length_c   6.62
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   6
_chemical_formula_structural   Ta3Nb5
_chemical_formula_sum   'Ta6 Nb10'
_cell_volume   290.49
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '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  Ta0  2  0.34  0.34  0.31  1.0
  Ta  Ta1  1  0.01  0.0  0.31  1.0
  Ta  Ta2  1  0.02  0.0  0.65  1.0
  Ta  Ta3  1  0.02  0.0  0.97  1.0
  Ta  Ta4  1  0.68  0.0  0.0  1.0
  Nb  Nb5  2  0.34  0.33  0.0  1.0
  Nb  Nb6  2  0.68  0.34  0.65  1.0
  Nb  Nb7  2  0.68  0.34  0.97  1.0
  Nb  Nb8  1  0.01  0.0  0.0  1.0
  Nb  Nb9  1  0.34  0.0  0.65  1.0
  Nb  Nb10  1  0.34  0.0  0.97  1.0
  Nb  Nb11  1  0.68  0.0  0.31  1.0

Ta Ta Ta Ta Ta Ta Nb Nb Nb Nb Nb Nb Nb Nb Nb Nb
Ta3Nb5 crystallizes in the monoclinic Pm space group. There are five inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 3-coordinate geometry to one Ta(3), one Nb(1), and one Nb(5) atom. The Ta(1)-Ta(3) bond length is 2.26 Å. The Ta(1)-Nb(1) bond length is 2.06 Å. The Ta(1)-Nb(5) bond length is 2.18 Å. In the second Ta site, Ta(2) is bonded in a 1-coordinate geometry to one Nb(2) atom. The Ta(2)-Nb(2) bond length is 2.06 Å. In the third Ta site, Ta(3) is bonded in a 5-coordinate geometry to one Ta(1), one Ta(4), one Nb(6), and two equivalent Nb(3) atoms. The Ta(3)-Ta(4) bond length is 2.11 Å. The Ta(3)-Nb(6) bond length is 2.10 Å. Both Ta(3)-Nb(3) bond lengths are 3.20 Å. In the fourth Ta site, Ta(4) is bonded in a single-bond geometry to one Ta(3), one Nb(1), and one Nb(7) atom. The Ta(4)-Nb(1) bond length is 0.23 Å. The Ta(4)-Nb(7) bond length is 2.10 Å. In the fifth Ta site, Ta(5) is bonded in a square pyramidal geometry to one Nb(1), one Nb(5), one Nb(7), and two equivalent Nb(4) atoms. The Ta(5)-Nb(1) bond length is 2.19 Å. The Ta(5)-Nb(5) bond length is 2.06 Å. The Ta(5)-Nb(7) bond length is 2.23 Å. Both Ta(5)-Nb(4) bond lengths are 2.27 Å. There are seven inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a single-bond geometry to one Ta(1), one Ta(4), and one Ta(5) atom. In the second Nb site, Nb(2) is bonded in a distorted rectangular see-saw-like geometry to one Ta(2), one Nb(2), one Nb(4), and one Nb(7) atom. The Nb(2)-Nb(2) bond length is 2.19 Å. The Nb(2)-Nb(4) bond length is 2.27 Å. The Nb(2)-Nb(7) bond length is 2.22 Å. In the third Nb site, Nb(3) is bonded in a 2-coordinate geometry to one Ta(3), one Nb(3), and one Nb(4) atom. The Nb(3)-Nb(3) bond length is 2.09 Å. The Nb(3)-Nb(4) bond length is 2.13 Å. In the fourth Nb site, Nb(4) is bonded in a distorted rectangular see-saw-like geometry to one Ta(5), one Nb(2), one Nb(3), and one Nb(4) atom. The Nb(4)-Nb(4) bond length is 2.09 Å. In the fifth Nb site, Nb(5) is bonded in a distorted L-shaped geometry to one Ta(1) and one Ta(5) atom. In the sixth Nb site, Nb(6) is bonded in a 2-coordinate geometry to one Ta(3) and one Nb(7) atom. The Nb(6)-Nb(7) bond length is 2.14 Å. In the seventh Nb site, Nb(7) is bonded in a distorted square pyramidal geometry to one Ta(4), one Ta(5), one Nb(6), and two equivalent Nb(2) atoms.