Vaporization of Compounds and Alloys at High Temperatures. Part XXIII. Thermochemical Study of the Germanium Oxides Using a Mass Spectrometer. The Dissociation Energy of the Molecule Geo

摘要

A mass spectrometric study of the vaporization of the compounds GeO2 (hex) and GeO(am) and of the mixture GeO2(hex) + Ge(c) made it possible to establish their mode of vaporization: (I) GeO2(hex) - GeO(g) + I/2O2; (II) n GeO(am) - (GeO)n(g) (n=1, 2, 3); (III) n/2 GeO2(hex) + n/2 Ge(c) - (GeO)n(g) (n = 1, 2, 3). The enthalpies of vaporization at 298K are: (I) = 121.2=1.6 kcal/mole; (II, n = 1) = 53.4=1.0 kcal/mole; (III, n = 1) = 58.2=1.0 kcal/mole. The polymerization energies at 298K are: (GeO-GeO) = 44.7=3.0 kcal/mole; (GeO-GeO-GeO)= 88.5=5.0 kcal/mole. Total pressures given in the literatuure were reinterpreted taking the presence of the polymers into account. The heat of formation of the metastable compound GeO(am) obtained is -59.6 = 0.7 kcal/mole. The dissociation energy of the gaseous molecule GeO is 157.4=1.5 kcal/mole. (Author)