Thermal decompositions of formates. Part VII. Thermal decomposition of yttrium formate dihydrate

Abstract

The thermal dehydration of yttrium formate dihydrate and decomposition of yttrium formate anhydride were studied in flowing nitrogen and carbon dioxide atmospheres by means of TG and DTA. The dehydration reaction was not affected by the atmospheric condition and took place successively without any intermediate hydrate. The mechanism of the dehydration reaction was found to be a phase boundary controlled interface reaction. The decomposition of yttrium formate occurred in three stages, and yttrium oxyformate and yttrium oxycarbonate were formed as the intermediate products. In a carbon dioxide atmosphere, the decomposition took place at a higher temperature than in a nitrogen atmosphere. The anhydrous salt melted during the main stage of the decomposition and the kinetic behaviour of this stage was characteristic of a homogeneous first order reaction.