The TS1 stationary point exhibits an imaginary mode of 1726i as one of the water hydrogens begins to form a bond with the nitrogen atom, and the water oxygen begins to bond with the carbon. Natural Resonance Theory (NRT) predicts the bond order between the nitrogen and the water hydrogen to be 0.49 and the bond order of the nitrogen and carbon atoms to be 1.48 at TS1. Likewise, the carbon and water oxygen interaction exhibits a bond order of 0.56. The NBO second-order perturbation (E ) analysis indicates that the most significant delocalization corresponds to electron density donated from the water lone pair into one of the isocyanate C-O* orbitals (E (2) =144.2 kcal mol -1 ), which is depicted in Water and HNCO can alternatively react through TS2 which exhibits a 1718i imaginary mode as the water oxygen begins to form a bond with the isocyanate carbon and one of the water hydrogens begins to bond with the isocyanate oxygen. The new O HNCO -H water bond is predicted to have a NRT bond order of 0.32 while the carbon and water oxygen nearly exhibit a formal single bond order (0.90). The dominant E term in the TS2 structure (90.2 kcal mol -1 ) corresponds to delocalization of the isocyanate oxygen lone pair electron density into the most proximal water O-H* orbital as represented in Figure . The magnitude of this interaction is much smaller than the delocalization predicted in the TS1 structure and the preclusion of delocalization could be a partial explanation for why TS2 is much higher in energy. The product M2 of reaction through TS2 is the planar hydroxylated imidic acid molecule which lies only 2.8 kcal mol -1 higher in energy than water + HNCO. NBO computations indicate that M2 also exhibits significant delocalization as electron density from both hydroxyl groups is donated into the out of plane C-N* orbital. M2 also has two other conformers which correspond to rotations of the hydroxyl groups and are predicted to have estimated CCSDT(Q)/CBS energies of 2.0 and 5.1 kcal mol -1 relative to M2.