Reaction of Ce(NO3)(3)(THF)(4) with Li-3(THF)(3)(NN'(3)) (NN'(3) = N(CH2CH2NR)(3), R = (SiBuMe2)-Bu-t) in Et2O, in the presence of 12-crown-4, results in the formation of [Li(12-crown-4)][(NN'3)Ce(O)] (1) in 36% yield. This transformation proceeds via formation of a Ce(III) nitrate intermediate, [Li(12-crown-4)][(NN'(3))Ce(k(2)-O2NO)] (2), which undergoes inner sphere nitrate reduction. In addition, reaction of 1 with tBuMe2SiCl results in the formation of (NN'(3))Ce((OSiBuMe2)-Bu-t) (3), confirming the nucleophilic character of its oxo ligand. Natural bond orbital and quantum theory of atoms-in-molecules data reveal the Ce-O interaction in 1 to be significantly covalent, and strikingly similar to analogous U-O bonding.