Uranium terminal mono-oxo complexes are prepared with a unique activation of nitrite following reductive cleavage of an N-O bond with loss of nitric oxide. The thermodynamic driving force of U=O bond formation differentiates this reactivity from known mechanisms of nitrite reduction, which are typically mediated by proton transfer. Mechanistic details are explored by DFT supporting a simple homolytic cleavage pathway from a kappa(1)-ONO bound intermediate. Complexes of the formula (UOX)-O-VI[N(SiMe3)(2)](3) are formed providing a trigonal bipyramidal framework into which ligands trans to the U=O bond may be installed.