Germanium‐Iodine System, Thermodynamic Study assessment and complementary experiments

Abstract

AbstractLiterature thermodynamic data (enthalpies, entropies, and heat capacities) of the condensed species GeI4(s)(I) and GeI2(s) are revised.Entropies and heat capacities of the gaseous species GeI4(g), GeI2(g), and GeI(g) are calculated by the R.R.H.O. method. Published experimental investigations of the equilibria: GeI4(l) ⇌ GeI4(g), GeI4(s) ⇌ GeI4(g), 2 GeI2 ⇌ Ge(s) + GeI4(g), GeI4 ⇌ GeI2(g) + I2(g), GeI2(s) ⇌ GeI2(g) and Ge(s) + GeI4(g) ⇌ 2 GeI2(g) are discussed. In addition, new measurements of the total pressure above the saturation ranges of the GeI4(l) and for the reaction: Ge(s) + GeI4(l) ⇌ 2 GeI2(g) are performed.Enthalpies of formation of GeI4(g) and GeI(g) are deduced. Enthalpy of formation of GeI(g) is estimated from the evolution of the dissociation energy D°(GeX) (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.