data_Nb2Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.13
_cell_length_b   3.13
_cell_length_c   6.15
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Nb2Cu
_chemical_formula_sum   'Nb2 Cu1'
_cell_volume   52.16
_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  Nb1  1  0.0  0.81  0.03  1.0
  Nb  Nb2  1  0.56  0.9  0.12  1.0
  Cu  Cu0  1  0.0  0.0  0.0  1.0

data_Nb2Cu
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.13
_cell_length_b   3.13
_cell_length_c   6.15
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Nb2Cu
_chemical_formula_sum   'Nb2 Cu1'
_cell_volume   52.16
_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  0.0  0.81  0.03  1.0
  Nb  Nb1  1  0.56  0.9  0.12  1.0
  Cu  Cu2  1  0.0  0.0  0.0  1.0

Nb Nb Cu
Nb Nb Cu 0 2 o + o 0 1 o o o 0 1 - o o 1 2 + + o 
NbCuNb crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one NbCuNb cluster. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a single-bond geometry to one Cu(1) atom. The Nb(1)-Cu(1) bond length is 0.64 Å. In the second Nb site, Nb(2) is bonded in a distorted single-bond geometry to one Cu(1) atom. The Nb(2)-Cu(1) bond length is 1.45 Å. Cu(1) is bonded in a distorted L-shaped geometry to one Nb(1) and one Nb(2) atom.