The thermal decomposition of curium(III) oxalate IO-hydrate

Abstract

Previous studies on the thermal decomposition of the lanthanide oxalates have used relatively large samples. For a study of the thermal decomposition of curium oxalate we have sought to evolve a method utilizing less than one mg of material. By continuously analyzing the gaseous reaction products with a mass spectrometer, a study of the thermal decomposition of curium oxalate has been made with ∼ 100 μg of sample. Curium(III) oxalate hydrate may be dehydrated in vacuum at a temperature as low as 280°C, and decomposition of oxalate itself takes place with completion of the dehydration step. Carbon monoxide, formed initially during decomposition of the oxalate, is thought to undergo disproportionation into carbon and carbon dioxide, a process which occurs to the extent of nearly 60 per cent in the first stages of decomposition. By gradually increasing the temperature, further decomposition takes place and various intermediates which appear to correspond to phases of definite composition are observed. These phases are contaminated with finely dispersed carbon. The compositions of all intermediate phases obtained in the temperature range 280–700°C are summarized.