Kinetics of dehydration of single crystals of uranyl nitrate hexahydrate

Abstract

The kinetics of dehydration of single crystals of uranyl nitrate hexahydrate to uranyl nitrate trihydrate have been followed isothermally, in vacuo from –60 to –30 °C. The energy of activation for the dehydration is 46 ± 4 kJ (mol H2O)–1. The dependence of the rate of dehydration upon the ambient water vapour pressure is linear which is unusual. Although the product is crystalline and this is a non-zeolitic dehydration process, it does not occur at the reactant–product interface and, consequently, the usual contracting envelope kinetics do not apply.