data_K2BiBr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.78
_cell_length_b   3.78
_cell_length_c   9.58
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2BiBr
_chemical_formula_sum   'K2 Bi1 Br1'
_cell_volume   137.02
_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
  K  K2  1  0.89  0.89  0.04  1.0
  K  K3  1  0.89  0.89  0.54  1.0
  Bi  Bi0  1  0.0  0.0  0.79  1.0
  Br  Br1  1  0.0  0.0  0.0  1.0

data_K2BiBr
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.35
_cell_length_b   5.35
_cell_length_c   9.58
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   K2BiBr
_chemical_formula_sum   'K4 Bi2 Br2'
_cell_volume   274.04
_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
  K  K0  2  0.39  0.5  0.04  1.0
  K  K1  2  0.39  0.5  0.54  1.0
  Bi  Bi2  2  0.0  0.0  0.79  1.0
  Br  Br3  2  0.0  0.0  0.0  1.0

K K Bi Br
K2BiBr crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two K2BiBr clusters. There are two inequivalent K sites. In the first K site, K(1) is bonded in a single-bond geometry to one Br(1) atom. The K(1)-Br(1) bond length is 0.72 Å. In the second K site, K(2) is bonded in a single-bond geometry to one Bi(1) atom. The K(2)-Bi(1) bond length is 2.50 Å. Bi(1) is bonded in a linear geometry to one K(2) and one Br(1) atom. The Bi(1)-Br(1) bond length is 2.01 Å. Br(1) is bonded in a distorted single-bond geometry to one K(1) and one Bi(1) atom.