Thermal behavior and decomposition of cerium(III) butanoate, pentanoate and hexanoate salts upon heating in argon

Abstract The thermal behavior and decomposition of Ce-butanoate monohydrate (Ce(C 3 H 7 CO 2 ) 3 ·H 2 O), Ce-pentanoate (Ce(C 4 H 9 CO 2 ) 3 ) and Ce-hexanoate (Ce(C 5 H 11 CO 2 ) 3 ) were studied in a flow of argon while heating at 5 °C/min. By means of several techniques such as simultaneous TG-DTA, FTIR evolved gas analysis, in-situ x-ray diffraction using a synchrotron source and hot-stage microscopy, it was found that all three compounds undergo melting transitions prior to decomposition and that decomposition involves intermediate stages including at least a Ce 2 O(C n H 2n+1 CO 2 ) 4 intermediate (n = 3, 4 or 5 for Ce-butanoate, pentanoate or hexanoate respectively). The final decomposition product consists of CeO 2 , which is formed through a Ce-oxycarbonate. The Ce 3+  → Ce 4+ oxidation seems to proceed via Ce 2 O 3 that first results from the decomposition of the oxycarbonate phase. During the whole decomposition process, the evolved gas species consist of CO 2 and symmetrical ketones.