Uranium hexoxide is predicted to have octahedral symmetry; however, other forms have been studied. In the 1Oh the oxygen atoms are oxide ions (O2-). In the 1D3 form there are three peroxide ions (O22-). The 3D2h form has two oxo oxygens and two pairs of superoxide (O2-).
^ abXiao, H.; Hu, H. S.; Schwarz, W. H. E.; Li, J. (2010). "Theoretical Investigations of Geometry, Electronic Structure and Stability of UO6: Octahedral Uranium Hexoxide and Its Isomers". The Journal of Physical Chemistry A114 (33): 8837–8844. doi:10.1021/jp102107n. PMID20572656.edit