Thermal decomposition of yttrium(III) propionate and butyrate

The thermal decompositions of yttrium(III) propionate monohydrate (Y(C2H5CO2)3·H2O) and yttrium(III) butyrate dihydrate (Y(C3H7CO2)3·2H2O) were studied in argon by means of thermogravimetry, differential thermal analysis, IR-spectroscopy, X-ray diffraction and hot-stage microscopy. These two compounds follow a similar decomposition path starting with dehydration, which is complete at 110 °C. The dehydrated salts convert to a dioxycarbonate (Y2O2CO3) via an unstable intermediate product (probably Y2O(C2H5CO2)4 and Y2O(C3H7CO2)4 for the propionate and butyrate respectively), with the evolution of CO2 and a symmetrical ketone consisting of 3-pentanone and 4-heptanone respectively. Final conversion to Y2O3 takes pace with release of CO2. Elemental carbon that is left as a by-product is finally slowly burned by the residual oxygen present in the Ar atmosphere. Fusion is observed at ≈110 °C in anhydrous yttrium butyrate, whereas no melting was evidenced in the propionate.