The structure described by UO3 crystallizes in the orthorhombic Fddd space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second U site, U(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form edge-sharing UO6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one U(1) and one U(2) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one U(1) and two equivalent U(2) atoms. In the third O site, O(3) is bonded in a single-bond geometry to one U(1) atom. is represented by the CIF card [CIF]
data_UO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.302
_cell_length_b   11.281
_cell_length_c   6.974
_cell_angle_alpha   72.183
_cell_angle_beta   71.840
_cell_angle_gamma   35.977
_symmetry_Int_Tables_number   1
_cell_volume   494.045
_cell_formula_units_Z   8
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  0.811  0.811  0.189  1.0
  U  U1  1  0.189  0.189  0.811  1.0
  U  U2  1  0.439  0.439  0.061  1.0
  U  U3  1  0.061  0.061  0.439  1.0
  U  U4  1  0.625  0.625  0.125  1.0
  U  U5  1  0.125  0.625  0.625  1.0
  U  U6  1  0.625  0.625  0.625  1.0
  U  U7  1  0.625  0.125  0.625  1.0
  O  O8  1  0.716  0.718  0.085  1.0
  O  O9  1  0.085  0.481  0.716  1.0
  O  O10  1  0.718  0.716  0.481  1.0
  O  O11  1  0.481  0.085  0.718  1.0
  O  O12  1  0.534  0.532  0.165  1.0
  O  O13  1  0.165  0.769  0.534  1.0
  O  O14  1  0.532  0.534  0.769  1.0
  O  O15  1  0.769  0.165  0.532  1.0
  O  O16  1  0.855  0.862  0.835  1.0
  O  O17  1  0.835  0.448  0.855  1.0
  O  O18  1  0.862  0.855  0.448  1.0
  O  O19  1  0.448  0.835  0.862  1.0
  O  O20  1  0.395  0.388  0.415  1.0
  O  O21  1  0.415  0.802  0.395  1.0
  O  O22  1  0.388  0.395  0.802  1.0
  O  O23  1  0.802  0.415  0.388  1.0
  O  O24  1  0.199  0.183  0.549  1.0
  O  O25  1  0.549  0.069  0.199  1.0
  O  O26  1  0.183  0.199  0.069  1.0
  O  O27  1  0.069  0.549  0.183  1.0
  O  O28  1  0.051  0.067  0.701  1.0
  O  O29  1  0.701  0.181  0.051  1.0
  O  O30  1  0.067  0.051  0.181  1.0
  O  O31  1  0.181  0.701  0.067  1.0
[/CIF]
.
The structure described by UO3 crystallizes in the orthorhombic Fddd space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second U site, U(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form edge-sharing UO6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one U(1) and one U(2) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one U(1) and two equivalent U(2) atoms. In the third O site, O(3) is bonded in a single-bond geometry to one U(1) atom. is represented by the CIF card [CIF]
data_UO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.302
_cell_length_b   11.281
_cell_length_c   6.974
_cell_angle_alpha   72.183
_cell_angle_beta   71.840
_cell_angle_gamma   35.977
_symmetry_Int_Tables_number   1
_cell_volume   494.045
_cell_formula_units_Z   8
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  0.811  0.811  0.189  1.0
  U  U1  1  0.189  0.189  0.811  1.0
  U  U2  1  0.439  0.439  0.061  1.0
  U  U3  1  0.061  0.061  0.439  1.0
  U  U4  1  0.625  0.625  0.125  1.0
  U  U5  1  0.125  0.625  0.625  1.0
  U  U6  1  0.625  0.625  0.625  1.0
  U  U7  1  0.625  0.125  0.625  1.0
  O  O8  1  0.716  0.718  0.085  1.0
  O  O9  1  0.085  0.481  0.716  1.0
  O  O10  1  0.718  0.716  0.481  1.0
  O  O11  1  0.481  0.085  0.718  1.0
  O  O12  1  0.534  0.532  0.165  1.0
  O  O13  1  0.165  0.769  0.534  1.0
  O  O14  1  0.532  0.534  0.769  1.0
  O  O15  1  0.769  0.165  0.532  1.0
  O  O16  1  0.855  0.862  0.835  1.0
  O  O17  1  0.835  0.448  0.855  1.0
  O  O18  1  0.862  0.855  0.448  1.0
  O  O19  1  0.448  0.835  0.862  1.0
  O  O20  1  0.395  0.388  0.415  1.0
  O  O21  1  0.415  0.802  0.395  1.0
  O  O22  1  0.388  0.395  0.802  1.0
  O  O23  1  0.802  0.415  0.388  1.0
  O  O24  1  0.199  0.183  0.549  1.0
  O  O25  1  0.549  0.069  0.199  1.0
  O  O26  1  0.183  0.199  0.069  1.0
  O  O27  1  0.069  0.549  0.183  1.0
  O  O28  1  0.051  0.067  0.701  1.0
  O  O29  1  0.701  0.181  0.051  1.0
  O  O30  1  0.067  0.051  0.181  1.0
  O  O31  1  0.181  0.701  0.067  1.0
[/CIF]
.