The structure described by UO3 crystallizes in the tetragonal I4_1/amd space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form edge-sharing UO6 octahedra. In the second U site, U(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There are three inequivalent O sites. In the first O site, O(3) is bonded in a trigonal planar geometry to one U(2) and two equivalent U(1) atoms. In the second O site, O(1) is bonded in a single-bond geometry to one U(2) atom. In the third O site, O(2) is bonded in a bent 150 degrees geometry to one U(1) and one U(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_UO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.244
_cell_length_b   11.244
_cell_length_c   11.244
_cell_angle_alpha   143.841
_cell_angle_beta   143.841
_cell_angle_gamma   52.065
_symmetry_Int_Tables_number   1
_cell_volume   492.037
_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  0.375  0.625  0.250  1.0
  U  U1  1  0.375  0.625  0.750  1.0
  U  U2  1  0.875  0.625  0.250  1.0
  U  U3  1  0.375  0.125  0.750  1.0
  U  U4  1  0.561  0.061  0.500  1.0
  U  U5  1  0.811  0.811  0.000  1.0
  U  U6  1  0.189  0.189  0.000  1.0
  U  U7  1  0.939  0.439  0.500  1.0
  O  O8  1  0.941  0.701  0.760  1.0
  O  O9  1  0.818  0.059  0.760  1.0
  O  O10  1  0.299  0.059  0.240  1.0
  O  O11  1  0.809  0.068  0.260  1.0
  O  O12  1  0.809  0.549  0.740  1.0
  O  O13  1  0.451  0.191  0.260  1.0
  O  O14  1  0.932  0.191  0.740  1.0
  O  O15  1  0.941  0.182  0.240  1.0
  O  O16  1  0.282  0.083  0.801  1.0
  O  O17  1  0.833  0.532  0.301  1.0
  O  O18  1  0.232  0.532  0.699  1.0
  O  O19  1  0.468  0.768  0.301  1.0
  O  O20  1  0.468  0.167  0.699  1.0
  O  O21  1  0.518  0.718  0.801  1.0
  O  O22  1  0.917  0.718  0.199  1.0
  O  O23  1  0.282  0.482  0.199  1.0
  O  O24  1  0.141  0.833  0.693  1.0
  O  O25  1  0.583  0.391  0.193  1.0
  O  O26  1  0.198  0.391  0.807  1.0
  O  O27  1  0.609  0.802  0.193  1.0
  O  O28  1  0.609  0.417  0.807  1.0
  O  O29  1  0.552  0.859  0.693  1.0
  O  O30  1  0.167  0.859  0.307  1.0
  O  O31  1  0.141  0.448  0.307  1.0
[/CIF]
.
The structure described by UO3 crystallizes in the tetragonal I4_1/amd space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form edge-sharing UO6 octahedra. In the second U site, U(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There are three inequivalent O sites. In the first O site, O(3) is bonded in a trigonal planar geometry to one U(2) and two equivalent U(1) atoms. In the second O site, O(1) is bonded in a single-bond geometry to one U(2) atom. In the third O site, O(2) is bonded in a bent 150 degrees geometry to one U(1) and one U(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_UO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.244
_cell_length_b   11.244
_cell_length_c   11.244
_cell_angle_alpha   143.841
_cell_angle_beta   143.841
_cell_angle_gamma   52.065
_symmetry_Int_Tables_number   1
_cell_volume   492.037
_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  0.375  0.625  0.250  1.0
  U  U1  1  0.375  0.625  0.750  1.0
  U  U2  1  0.875  0.625  0.250  1.0
  U  U3  1  0.375  0.125  0.750  1.0
  U  U4  1  0.561  0.061  0.500  1.0
  U  U5  1  0.811  0.811  0.000  1.0
  U  U6  1  0.189  0.189  0.000  1.0
  U  U7  1  0.939  0.439  0.500  1.0
  O  O8  1  0.941  0.701  0.760  1.0
  O  O9  1  0.818  0.059  0.760  1.0
  O  O10  1  0.299  0.059  0.240  1.0
  O  O11  1  0.809  0.068  0.260  1.0
  O  O12  1  0.809  0.549  0.740  1.0
  O  O13  1  0.451  0.191  0.260  1.0
  O  O14  1  0.932  0.191  0.740  1.0
  O  O15  1  0.941  0.182  0.240  1.0
  O  O16  1  0.282  0.083  0.801  1.0
  O  O17  1  0.833  0.532  0.301  1.0
  O  O18  1  0.232  0.532  0.699  1.0
  O  O19  1  0.468  0.768  0.301  1.0
  O  O20  1  0.468  0.167  0.699  1.0
  O  O21  1  0.518  0.718  0.801  1.0
  O  O22  1  0.917  0.718  0.199  1.0
  O  O23  1  0.282  0.482  0.199  1.0
  O  O24  1  0.141  0.833  0.693  1.0
  O  O25  1  0.583  0.391  0.193  1.0
  O  O26  1  0.198  0.391  0.807  1.0
  O  O27  1  0.609  0.802  0.193  1.0
  O  O28  1  0.609  0.417  0.807  1.0
  O  O29  1  0.552  0.859  0.693  1.0
  O  O30  1  0.167  0.859  0.307  1.0
  O  O31  1  0.141  0.448  0.307  1.0
[/CIF]
.