data_U
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.48
_cell_length_b   8.48
_cell_length_c   8.48
_cell_angle_alpha   21.15
_cell_angle_beta   21.15
_cell_angle_gamma   21.15
_symmetry_Int_Tables_number   1
_chemical_formula_structural   U
_chemical_formula_sum   U3
_cell_volume   69.57
_cell_formula_units_Z   3
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  U0  1  0.0  0.0  0.0  1.0
  U  U1  1  0.0  0.0  0.33  1.0
  U  U2  1  0.0  0.0  0.54  1.0

data_U
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.39
_cell_length_b   3.11
_cell_length_c   8.48
_cell_angle_alpha   90.0
_cell_angle_beta   102.23
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   U
_chemical_formula_sum   U6
_cell_volume   139.14
_cell_formula_units_Z   6
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  0.0  0.0  0.0  1.0
  U  U1  2  0.0  0.0  0.46  1.0
  U  U2  2  0.0  0.0  0.67  1.0

U U U
U crystallizes in the monoclinic Cm space group. There are four inequivalent U sites. In the first U site, U(1) is bonded in a 8-coordinate geometry to one U(2); one U(3); and six U(1,1) atoms. The U(1)-U(2) bond length is 2.77 Å. The U(1)-U(3) bond length is 3.89 Å. All U(1)-U(1,1) bond lengths are 3.11 Å. In the second U site, U(2) is bonded in a distorted single-bond geometry to one U(1) and one U(3) atom. The U(2)-U(3) bond length is 1.82 Å. In the third U site, U(3) is bonded in a single-bond geometry to one U(1) and one U(2) atom. In the fourth U site, U(1) is bonded in a 8-coordinate geometry to one U(2); one U(3); and six U(1,1) atoms. The U(1)-U(2) bond length is 2.77 Å. The U(1)-U(3) bond length is 3.89 Å. Both U(1)-U(1) bond lengths are 3.11 Å.