Sublimation and Dissociation of Thl₄ and ThOl₂ from Knudsen Cells

Abstract

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.

Determination by Mass Spectrometry of the Partial Pressures of SnO, Sn2O2, Sn4O4 and Sn6O6 in Equilibrium with Oxygen Saturated Tin Melts

“…The total vapour pressure in the large cell is reduced to about 30% of the equilibrium pressure. Applying the relationship of Motzfeldt [11] or Flesch et al [12], a reduction in the vapourization rate at the melt surface can be shown to be of the order of 104. In the small cells the total pressure attained only 10% of the equilibrium pressure, the calculations revealing the same hindrance.…”