Sublimation and Dissociation of Thl4 and ThOl2 from Knudsen Cells

The sublimation pressure of ThI₄ has been measured by the Knudsen effusion method and found to be . Simultaneously with the sublimation of ThI₄ there is a small dissociation to lower iodide and iodine. The dissociation pressure associated with the reaction 2 ThOI₂ = ThO₂ + ThI₄ is The molar heat capacity of solid ThI₄ 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 ThOI₂ is calculated to be 145 J K^?1 mol^?1.