data_Nb2PbBr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.52
_cell_length_b   3.52
_cell_length_c   7.91
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Nb2PbBr
_chemical_formula_sum   'Nb2 Pb1 Br1'
_cell_volume   98.09
_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  0.76  0.76  0.3  1.0
  Nb  Nb2  1  0.0  0.0  0.51  1.0
  Pb  Pb3  1  0.76  0.76  0.46  1.0
  Br  Br0  1  0.0  0.0  0.6  1.0

data_Nb2PbBr
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.98
_cell_length_b   4.98
_cell_length_c   7.91
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Nb2PbBr
_chemical_formula_sum   'Nb4 Pb2 Br2'
_cell_volume   196.17
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.51  1.0
  Nb  Nb1  2  0.26  0.5  0.3  1.0
  Pb  Pb2  2  0.26  0.5  0.46  1.0
  Br  Br3  2  0.0  0.0  0.6  1.0

Nb Nb Pb Br
Nb2PbBr crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Nb2PbBr clusters. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a single-bond geometry to one Pb(1) atom. The Nb(1)-Pb(1) bond length is 1.27 Å. In the second Nb site, Nb(2) is bonded in a distorted water-like geometry to one Pb(1) and one Br(1) atom. The Nb(2)-Pb(1) bond length is 1.25 Å. The Nb(2)-Br(1) bond length is 0.74 Å. Pb(1) is bonded in a water-like geometry to one Nb(1) and one Nb(2) atom. Br(1) is bonded in a single-bond geometry to one Nb(2) atom.