The reactions of acetone oxime, a proposed reaction intermediate for the selective catalytic reduction (SCR) of NO with propane on CuZSM-5 and on HZSM-5, have been studied with C-13 and N-15 solid-state magic-angle spinning nuclear magnetic resonance (MAS NMR). The carbon- and/or nitrogen-containing surface species, as well as the products formed under conditions of thermodynamic equilibrium, have been monitored and identified. In the absence of NO and after heating to 150-200 degrees C, the main hydrolysis products of adsorbed acetone oxime on CuZSM-5 are acetone and hydroxylamine, while the main hydrolysis products on HZSM-5 are acetic acid and methylamine. In addition, N-2 and N2O are formed from acetone oxime adsorbed on both HZSM-5 and CuZSM-5. In the presence of (NO)-N-15, the observation of mixed-labeled (NNO)-N-14-N-15 and (NNO)-N-15-N-14 shows that new N-N bonds are formed over CuZSM-5 and HZSM-5 between two different nitrogen atoms: one from gaseous (NO)-N-15 molecules and the other from adsorbed acetone oxime and/or acetone oxime hydrolysis products. When (NO)-N-15 and unlabeled acetone oxime are reacted on CuZSM-5, the (NNO)-N-14-N-15/(NNO)-N-15-N-14 ratio is approximately 3, suggesting that the NO bond of gas-phase NO remains intact when it reacts with acetone oxime to form N2O. It is also found that the formation of new N-N bonds from the reaction of NO and acetone oxime occurs at room temperature on CuZSM-5, but not until similar to 150 degrees C on HZSM-5.