Heats of formation of germanium tetrafluoride and of the germanium dioxides

Abstract

The heats of fluorination of germanium and of hexagonal and tetragonal germanium dioxide have been determined calorimetrically by reacting them with fluorine gas. The heat of transition of vitreous into hexagonal germanium dioxide has been determined by solution calorimetry in hydrofluoric acid. The following data have been obtained: ΔH^°_{f 298}, GeF₄(g)=–284.37±0.15 kcal/mole; ΔH^°_{f 298}, GeO₂(c. hex)=–132.58±0.19 kcal/mole; ΔH^°_{f 298}, GeO₂(c. tetrag.)=–138.66±0.31 kcal/mole; ΔH^°_trans.298, GeO₂(c. hex)→GeO₂(c. tetrag.)=–6.08±0.34 kcal/mole; ΔH^°_trans.298, GeO₂(glass)→GeO₂(c. hex)=–3.75±0.14 kcal/mole.