data_Ta2Nb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.45
_cell_length_b   8.45
_cell_length_c   2.71
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2Nb
_chemical_formula_sum   'Ta6 Nb3'
_cell_volume   167.25
_cell_formula_units_Z   3
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  Ta3  1  0.64  0.36  0.35  1.0
  Ta  Ta4  1  0.23  0.8  0.0  1.0
  Ta  Ta5  1  0.73  0.0  0.35  1.0
  Ta  Ta6  1  0.86  0.95  0.35  1.0
  Ta  Ta7  1  0.54  0.0  0.0  1.0
  Ta  Ta8  1  0.45  0.51  0.0  1.0
  Nb  Nb0  1  0.0  0.0  0.0  1.0
  Nb  Nb1  1  0.0  0.88  0.35  1.0
  Nb  Nb2  1  0.22  0.44  0.35  1.0

data_Ta2Nb
_symmetry_space_group_name_H-M   P1
_cell_length_a   2.71
_cell_length_b   8.45
_cell_length_c   8.45
_cell_angle_alpha   120.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2Nb
_chemical_formula_sum   'Ta6 Nb3'
_cell_volume   167.25
_cell_formula_units_Z   3
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  Ta0  1  0.0  0.23  0.8  1.0
  Ta  Ta1  1  0.0  0.45  0.51  1.0
  Ta  Ta2  1  0.0  0.54  0.0  1.0
  Ta  Ta3  1  0.35  0.64  0.36  1.0
  Ta  Ta4  1  0.35  0.73  0.0  1.0
  Ta  Ta5  1  0.35  0.86  0.95  1.0
  Nb  Nb6  1  0.0  0.0  0.0  1.0
  Nb  Nb7  1  0.35  0.0  0.88  1.0
  Nb  Nb8  1  0.35  0.22  0.44  1.0

Ta Ta Ta Ta Ta Ta Nb Nb Nb
Ta Ta Ta Ta Ta Ta Nb Nb Nb 0 5 o o o 0 5 o o + 0 4 o o o 0 0 o o + 1 7 o o - 1 7 o o o 1 1 o o + 1 4 o + o 2 3 o - o 2 4 o o o 3 7 + o o 3 6 + + o 5 8 o o o 6 7 o - o 
Ta2Nb crystallizes in the triclinic P1 space group. There are six inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to two equivalent Ta(1), two equivalent Ta(5), two equivalent Ta(6), and one Nb(2) atom. Both Ta(1)-Ta(1) bond lengths are 2.71 Å. There is one shorter (2.92 Å) and one longer (3.27 Å) Ta(1)-Ta(5) bond length. There is one shorter (2.64 Å) and one longer (3.02 Å) Ta(1)-Ta(6) bond length. The Ta(1)-Nb(2) bond length is 3.86 Å. In the second Ta site, Ta(2) is bonded in a 6-coordinate geometry to one Ta(5), two equivalent Ta(2), one Nb(3), and two equivalent Nb(2) atoms. The Ta(2)-Ta(5) bond length is 2.33 Å. Both Ta(2)-Ta(2) bond lengths are 2.71 Å. The Ta(2)-Nb(3) bond length is 3.19 Å. There is one shorter (2.50 Å) and one longer (2.90 Å) Ta(2)-Nb(2) bond length. In the third Ta site, Ta(3) is bonded in a 2-coordinate geometry to one Ta(4) and one Ta(5) atom. The Ta(3)-Ta(4) bond length is 1.35 Å. The Ta(3)-Ta(5) bond length is 1.83 Å. In the fourth Ta site, Ta(4) is bonded in a 4-coordinate geometry to one Ta(3), one Nb(2), and two equivalent Nb(1) atoms. The Ta(4)-Nb(2) bond length is 1.61 Å. There is one shorter (1.42 Å) and one longer (2.04 Å) Ta(4)-Nb(1) bond length. In the fifth Ta site, Ta(5) is bonded in a 1-coordinate geometry to one Ta(2), one Ta(3), and two equivalent Ta(1) atoms. In the sixth Ta site, Ta(6) is bonded in a 1-coordinate geometry to two equivalent Ta(1) and one Nb(3) atom. The Ta(6)-Nb(3) bond length is 1.95 Å. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 1-coordinate geometry to two equivalent Ta(4) and one Nb(2) atom. The Nb(1)-Nb(2) bond length is 1.42 Å. In the second Nb site, Nb(2) is bonded in a 2-coordinate geometry to one Ta(1), one Ta(4), two equivalent Ta(2), and one Nb(1) atom. In the third Nb site, Nb(3) is bonded in a 1-coordinate geometry to one Ta(2) and one Ta(6) atom.