data_Ta3Nb4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.47
_cell_length_b   5.47
_cell_length_c   5.13
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta3Nb4
_chemical_formula_sum   'Ta3 Nb4'
_cell_volume   132.91
_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  Ta4  1  0.73  0.0  0.57  1.0
  Ta  Ta5  1  0.63  0.37  0.57  1.0
  Ta  Ta6  1  0.37  0.37  0.57  1.0
  Nb  Nb0  1  0.0  0.0  0.88  1.0
  Nb  Nb1  1  0.0  0.0  0.25  1.0
  Nb  Nb2  1  0.0  0.16  0.0  1.0
  Nb  Nb3  1  0.73  0.58  0.0  1.0

data_Ta3Nb4
_symmetry_space_group_name_H-M   P1
_cell_length_a   5.13
_cell_length_b   5.47
_cell_length_c   5.47
_cell_angle_alpha   120.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta3Nb4
_chemical_formula_sum   'Ta3 Nb4'
_cell_volume   132.91
_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  Ta0  1  0.57  0.37  0.37  1.0
  Ta  Ta1  1  0.57  0.63  0.37  1.0
  Ta  Ta2  1  0.57  0.73  0.0  1.0
  Nb  Nb3  1  0.0  -0.0  0.16  1.0
  Nb  Nb4  1  0.0  0.73  0.58  1.0
  Nb  Nb5  1  0.25  0.0  0.0  1.0
  Nb  Nb6  1  0.88  0.0  0.0  1.0

Ta Ta Ta Nb Nb Nb Nb
Ta Ta Ta Nb Nb Nb Nb 0 1 o o o 0 4 + o o 0 5 + o + 0 3 + o o 1 2 o o o 1 6 o o + 3 5 o o + 3 6 - - + 4 5 o o o 4 6 - - o 
Ta3Nb4 crystallizes in the triclinic P1 space group. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 3-coordinate geometry to one Ta(2), one Nb(1), and one Nb(2) atom. The Ta(1)-Ta(2) bond length is 2.34 Å. The Ta(1)-Nb(1) bond length is 2.16 Å. The Ta(1)-Nb(2) bond length is 2.16 Å. In the second Ta site, Ta(2) is bonded in a 1-coordinate geometry to one Ta(1), one Ta(3), and one Nb(4) atom. The Ta(2)-Ta(3) bond length is 1.45 Å. The Ta(2)-Nb(4) bond length is 2.44 Å. In the third Ta site, Ta(3) is bonded in a 3-coordinate geometry to one Ta(2), one Nb(1), and one Nb(2) atom. The Ta(3)-Nb(1) bond length is 2.57 Å. The Ta(3)-Nb(2) bond length is 2.57 Å. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 1-coordinate geometry to one Ta(1), one Ta(3), one Nb(3), and one Nb(4) atom. The Nb(1)-Nb(3) bond length is 1.06 Å. The Nb(1)-Nb(4) bond length is 2.11 Å. In the second Nb site, Nb(2) is bonded in a 3-coordinate geometry to one Ta(1), one Ta(3), and one Nb(3) atom. The Nb(2)-Nb(3) bond length is 1.57 Å. In the third Nb site, Nb(3) is bonded in a distorted L-shaped geometry to one Nb(1) and one Nb(2) atom. In the fourth Nb site, Nb(4) is bonded in a 2-coordinate geometry to one Ta(2) and one Nb(1) atom.