data_Nb2CuB
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.45
_cell_length_b   4.45
_cell_length_c   2.8
_cell_angle_alpha   91.93
_cell_angle_beta   91.93
_cell_angle_gamma   102.96
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Nb2CuB
_chemical_formula_sum   'Nb2 Cu1 B1'
_cell_volume   53.9
_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
  Nb  Nb2  1  0.31  0.26  0.4  1.0
  Nb  Nb3  1  0.31  0.74  0.4  1.0
  Cu  Cu1  1  0.77  0.0  0.0  1.0
  B  B0  1  0.0  0.0  0.0  1.0

data_Nb2CuB
_symmetry_space_group_name_H-M   P1
_cell_length_a   2.8
_cell_length_b   4.45
_cell_length_c   4.45
_cell_angle_alpha   102.96
_cell_angle_beta   91.93
_cell_angle_gamma   91.93
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Nb2CuB
_chemical_formula_sum   'Nb2 Cu1 B1'
_cell_volume   53.9
_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
  Nb  Nb0  1  0.4  0.31  0.26  1.0
  Nb  Nb1  1  0.4  0.31  0.74  1.0
  Cu  Cu2  1  0.0  0.77  0.0  1.0
  B  B3  1  0.0  0.0  0.0  1.0

Nb Nb Cu B
Nb Nb Cu B 0 3 o o o 0 3 o o + 0 1 o o o 0 1 o - o 1 3 o + o 1 3 o + + 1 2 o + o 1 2 o + + 2 3 + o o 
Nb2CuB crystallizes in the triclinic P1 space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 1-coordinate geometry to two equivalent Nb(2) and one B(1) atom. There is one shorter (2.14 Å) and one longer (2.31 Å) Nb(1)-Nb(2) bond length. The Nb(1)-B(1) bond length is 1.89 Å. In the second Nb site, Nb(2) is bonded in a 8-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), two equivalent Cu(1), and two equivalent B(1) atoms. Both Nb(2)-Nb(2) bond lengths are 2.80 Å. There is one shorter (2.44 Å) and one longer (2.64 Å) Nb(2)-Cu(1) bond length. There is one shorter (2.27 Å) and one longer (2.61 Å) Nb(2)-B(1) bond length. Cu(1) is bonded in a distorted single-bond geometry to two equivalent Nb(2) and one B(1) atom. The Cu(1)-B(1) bond length is 1.02 Å. B(1) is bonded in a 2-coordinate geometry to one Nb(1), two equivalent Nb(2), and one Cu(1) atom.