Thermal reactions of the mixed-valence iron fluorides, Fe2F5·nH2O

Publisher Website
Google Scholar
Abstract
The thermal reactions of Fe2F5·7H2O and Fe2F5·2H2O have been studied using a combination of thermogravimetric and differential thermogravimetric analysis and by differential scanning calorimetry. The initial dehydration of Fe2F5·7H2O near 100 °C is shown to be a complex process which leads to a fluoride-deficient phase of nominal composition Fe2F5·2H2O. Further heating leads to a product at the hemihydrate level. Isothermal dehydrations lead to two distinct high-temperature phases, but the formation of these materials is accompanied by both oxidation and fluoride loss. Vacuum dehydration of Fe2F5·7H2O leads to a fully mixed-valence monohydrate phase, which was previously prepared by dehydration in an HF atmosphere. Dehydration of the authentic crystalline Fe2F5·2H2O is seen to the distinguishable from the second-stage dehydration of Fe2F5·7H2O. Thermogravimetric analyses, thermodynamic measurements, and the kinetic parameters extracted from the several thermal techniques demonstrate that these two forms of ‘Fe2F5·2H2O’ differ significantly in their thermal reactions.

This publication has 0 references indexed in Scilit: