Germanium‐Iodine System, Thermodynamic Study assessment and complementary experiments

Literature thermodynamic data (enthalpies, entropies, and heat capacities) of the condensed species GeI 4 (s)(I) and GeI 2 (s) are revised. Entropies and heat capacities of the gaseous species GeI 4 (g), GeI 2 (g), and GeI(g) are calculated by the R.R.H.O. method. Published experimental investigations of the equilibria: GeI 4 (l) ⇌ GeI 4 (g), GeI 4 (s) ⇌ GeI 4 (g), 2 GeI 2 ⇌ Ge(s) + GeI 4 (g), GeI 4 ⇌ GeI 2 (g) + I 2 (g), GeI 2 (s) ⇌ GeI 2 (g) and Ge(s) + GeI 4 (g) ⇌ 2 GeI 2 (g) are discussed. In addition, new measurements of the total pressure above the saturation ranges of the GeI 4 (l) and for the reaction: Ge(s) + GeI 4 (l) ⇌ 2 GeI 2 (g) are performed. Enthalpies of formation of GeI 4 (g) and GeI(g) are deduced. Enthalpy of formation of GeI(g) is estimated from the evolution of the dissociation energy D°(GeX) (X = Cl, Br, I) against the Z atomic number and from the spectroscopic constants of this molecule. In conclusion a self consistent set of thermodynamic data concerning the germanium‐iodine system is proposed.