| Title:  Uranium Dioxide CAS Registry Number:  1344-57-6 Additional Names:  Uranous oxide;  black uranium oxide Molecular Formula:  O2U Molecular Weight:  270.03 Percent Composition:  O 11.85%, U 88.15% Line Formula:  UO2 Literature References:  Occurs in nature as the minerals uraninite or pitchblende.  Review of uranium oxides:  Keller in Comprehensive Inorganic Chemistry vol. 5, J. C. Bailar, Jr. et al., Eds. (Pergamon Press, Oxford, 1973) pp 224-233. Properties:  Brown to black powder, or cubic crystals.  d 10.97.  mp 2865°.  When obtained by heating the urano-uranic oxide or the oxalate in hydrogen, it is brown or copper-red in color and is pyrophoric.  Insol in water, dil acids; sol in concd acids. Melting point:  mp 2865° Density:  d 10.97 Use:  Nuclear fuel.  |