Quantum-chemical calculations of the possible interaction between CNN and NO have been performed at the CCSD(T)/aug-cc-PVTZ//B3LYP/6-31++G(d,p) level of theory. Fourteen conformers corresponding to local minima of potential energy and sixteen transition structures are located, and various possible reaction paths are probed. Products P3 - NCO + N-2 - and P4 - N2O + CN - were the two leading channels with slight energy barriers as compared to the reactants CNN + NO. Employing the Fukui functions and HSAB theory, we are able to rationalize the calculated outcomes. (C) 2007 Elsevier B.V. All rights reserved.