AbstractRaman spectra of SO2adsorbed on zeolites X, Y and A are reported together with a normal coordinate analysis of the various spectra of the adsorbed molecuar SO2. The data indicate that crystal‐like SO2is adsorbed on cation sites II and III of the zeolitic oxide framework. Internal SO2force constants quantifying adsorbate distortion are developed and compared with the frequency difference parameter,Δ(ν3–ν1). Raman spectral data also indicate the formation of several decomposition products of SO2, generated by surface reactions, which may include S 3−, S2, S4, SxO, SO 32−and SO 42−. Of these the lines attributed to S 3−, S2, S4and SxO exhibit