data_BaNb4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.37
_cell_length_b   5.37
_cell_length_c   5.37
_cell_angle_alpha   101.87
_cell_angle_beta   101.87
_cell_angle_gamma   126.06
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaNb4
_chemical_formula_sum   'Ba1 Nb4'
_cell_volume   111.63
_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
  Ba  Ba0  1  0.0  0.0  0.0  1.0
  Nb  Nb1  1  0.97  0.19  0.0  1.0
  Nb  Nb2  1  0.19  0.8  0.0  1.0
  Nb  Nb3  1  0.41  0.19  0.44  1.0
  Nb  Nb4  1  0.19  0.59  0.44  1.0

data_BaNb4
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.87
_cell_length_b   5.37
_cell_length_c   5.37
_cell_angle_alpha   78.13
_cell_angle_beta   63.03
_cell_angle_gamma   63.03
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaNb4
_chemical_formula_sum   'Ba1 Nb4'
_cell_volume   111.63
_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
  Ba  Ba0  1  0.0  0.0  0.0  1.0
  Nb  Nb1  1  0.15  0.44  0.61  1.0
  Nb  Nb2  1  0.19  -0.0  0.78  1.0
  Nb  Nb3  1  0.76  0.44  0.22  1.0
  Nb  Nb4  1  0.8  -0.0  0.39  1.0

Ba Nb Nb Nb Nb
Ba Nb Nb Nb Nb 0 1 - o o 0 2 o - o 0 3 o o o 0 4 o o o 1 4 + o o 2 3 o + o 2 4 o o o 2 4 o o - 3 4 o - o 3 4 o o o 
BaNb4 crystallizes in the triclinic P1 space group. Ba(1) is bonded in a 2-coordinate geometry to one Nb(1), one Nb(2), one Nb(3), and one Nb(4) atom. The Ba(1)-Nb(1) bond length is 1.13 Å. The Ba(1)-Nb(2) bond length is 1.89 Å. The Ba(1)-Nb(3) bond length is 2.38 Å. The Ba(1)-Nb(4) bond length is 3.66 Å. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a single-bond geometry to one Ba(1) and two equivalent Nb(4) atoms. There is one shorter (2.29 Å) and one longer (3.46 Å) Nb(1)-Nb(4) bond length. In the second Nb site, Nb(2) is bonded in a single-bond geometry to one Ba(1) and two equivalent Nb(4) atoms. There is one shorter (2.81 Å) and one longer (3.01 Å) Nb(2)-Nb(4) bond length. In the third Nb site, Nb(3) is bonded in a 1-coordinate geometry to one Ba(1) and three equivalent Nb(4) atoms. There are a spread of Nb(3)-Nb(4) bond distances ranging from 2.73-3.40 Å. In the fourth Nb site, Nb(4) is bonded in a 8-coordinate geometry to one Ba(1), two equivalent Nb(1), two equivalent Nb(2), and three equivalent Nb(3) atoms.