Reflected shock waves have been used to heat argon-diluted mixtures of nitrous oxide with cyanogen or hydrogen cyanide to temperatures between 1500 and 2000 °K. The NCN radical has been detected spectroscopically in both systems during the induction period to explosion. Results for the temperature dependence of the ignition delay suggest that nitrous oxide decomposition is rate controlling for C2N,-N2O mixtures whereas the reactions