data_Nb2CuBr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.62
_cell_length_b   5.62
_cell_length_c   5.62
_cell_angle_alpha   148.81
_cell_angle_beta   130.38
_cell_angle_gamma   59.78
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Nb2CuBr
_chemical_formula_sum   'Nb2 Cu1 Br1'
_cell_volume   69.28
_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  0.0  0.36  0.82  1.0
  Nb  Nb3  1  0.0  0.0  0.62  1.0
  Cu  Cu1  1  0.0  0.0  0.28  1.0
  Br  Br0  1  0.51  0.0  0.77  1.0

data_Nb2CuBr
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.02
_cell_length_b   4.71
_cell_length_c   5.62
_cell_angle_alpha   114.81
_cell_angle_beta   105.59
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Nb2CuBr
_chemical_formula_sum   'Nb2 Cu1 Br1'
_cell_volume   69.28
_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  0.18  0.54  0.54  1.0
  Nb  Nb1  1  0.38  0.38  0.38  1.0
  Cu  Cu2  1  0.72  0.72  0.72  1.0
  Br  Br3  1  0.74  0.23  0.74  1.0

Nb Nb Cu Br
Nb Nb Cu Br 0 1 o o o 0 2 o o o 0 2 o + + 0 3 o + + 0 3 o o o 1 2 o o o 1 3 o o o 2 3 o o o 2 3 - o - 
Nb2CuBr crystallizes in the triclinic P1 space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 3-coordinate geometry to two equivalent Nb(2), two equivalent Cu(1), and two equivalent Br(1) atoms. There is one shorter (1.20 Å) and one longer (2.34 Å) Nb(1)-Nb(2) bond length. There is one shorter (1.67 Å) and one longer (1.94 Å) Nb(1)-Cu(1) bond length. There is one shorter (2.57 Å) and one longer (2.71 Å) Nb(1)-Br(1) bond length. In the second Nb site, Nb(2) is bonded in a 5-coordinate geometry to two equivalent Nb(1), one Cu(1), and two equivalent Br(1) atoms. The Nb(2)-Cu(1) bond length is 1.91 Å. There is one shorter (2.41 Å) and one longer (3.35 Å) Nb(2)-Br(1) bond length. Cu(1) is bonded in a 5-coordinate geometry to one Nb(2), two equivalent Nb(1), and two equivalent Br(1) atoms. There is one shorter (2.35 Å) and one longer (2.36 Å) Cu(1)-Br(1) bond length. Br(1) is bonded in a 6-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), and two equivalent Cu(1) atoms.