data_UBr3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.59
_cell_length_b   5.59
_cell_length_c   5.59
_cell_angle_alpha   128.95
_cell_angle_beta   128.95
_cell_angle_gamma   75.09
_symmetry_Int_Tables_number   1
_chemical_formula_structural   UBr3
_chemical_formula_sum   'U1 Br3'
_cell_volume   103.13
_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
  U  U3  1  0.0  0.0  0.44  1.0
  Br  Br0  1  0.41  0.0  0.22  1.0
  Br  Br1  1  0.0  0.41  0.22  1.0
  Br  Br2  1  0.0  0.0  0.0  1.0

data_UBr3
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.82
_cell_length_b   6.82
_cell_length_c   5.59
_cell_angle_alpha   90.0
_cell_angle_beta   127.55
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   UBr3
_chemical_formula_sum   'U2 Br6'
_cell_volume   206.27
_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
  U  U0  2  0.06  0.5  0.56  1.0
  Br  Br1  4  0.49  0.29  0.19  1.0
  Br  Br2  2  0.0  0.0  0.0  1.0

U Br Br Br
UBr3 crystallizes in the monoclinic Cm space group. U(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Br(1) and two equivalent Br(2) atoms. Both U(1)-Br(1) bond lengths are 2.70 Å. There is one shorter (2.44 Å) and one longer (3.16 Å) U(1)-Br(2) bond length. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded in a 2-coordinate geometry to one U(1) and one Br(2) atom. The Br(1)-Br(2) bond length is 1.80 Å. In the second Br site, Br(2) is bonded in a distorted see-saw-like geometry to two equivalent U(1) and two equivalent Br(1) atoms.