In the present study, we have examined sulfation of cerium oxide via impregnation of (NH4)(2)SO4, followed by heating in the temperature range of 220-720 degrees C, using Raman Spec troscopy. Based on the S-O and S=O stretching frequencies in the range of 900-1400 cm(-1), a wide range of surface oxysulfur species and bulk cerium-oxy-sulfur species are identified. At 220 degrees C, a mixture of(NH4)(2)SO4 crystals, SO4(aq2-) and HSO4(aq1-) is found to have formed on ceria’s surface, whereas complete conversion of (NH4)(2)SO4 to SO4(aq2-) and HSO4(aq1-) occurs at 280 degrees C. At 350 degrees C, formation of a mixture of surface pyrosulfate S2O7(surf.02-, consisting of two S=O oscillators and a bulk type compound identified as Ce(IV)(SO4)(x)(SO3)(2-x) (0 < x < 2) have been observed. Upon introduction of moisture, the former transforms to HSO4(surf.1-), whereas the latter remains unchanged. At 400 degrees C, only the bulk type compound can be observed. At 450 degrees C, only Ce-2(SO4)(3) is generated and remains stable until 650 degrees C. Further increase in the temperature to 720 degrees C results in the formation of CeOSO4. The present study not only provides a more thorough understanding of the sulfation of cerium oxide at a molecular level, but also demonstrates that Raman spectroscopy is a highly effective technique to characterize sulfation of metal oxides.