Sublimation and Dissociation of Thl 4 and ThOl 2 from Knudsen Cells

The sublimation pressure of ThI 4 has been measured by the Knudsen effusion method and found to be\documentclass{article}\pagestyle{empty}\begin{document}$$ \lg {\rm p/bar} = - 11200/{\rm T} - 4.57{\rm lg T} + 24.81 $$\end{document} .Simultaneously with the sublimation of ThI 4 there is a small dissociation to lower iodide and iodine. The dissociation pressure associated with the reaction 2 ThOI 2 = ThO 2 + ThI 4 is\documentclass{article}\pagestyle{empty}\begin{document}$$ \lg {\rm p/bar} = - 15490/{\rm T} - 4.57\lg {\rm T} + 25.85 $$\end{document} The molar heat capacity of solid ThI 4 has been determined calorimetrically to be 146 J K −1 mol −1 , the heat of fusion is approximately 48 kJ mol −1 . The standard entropy of solid ThOI 2 is calculated to be 145 J K −1 mol −1 .