Mass-Spectrometric Studies at High Temperatures. II. The Dissociation Energies of the Monofluorides and Difluorides of Silicon and Germanium

Abstract

Calcium fluoride has been used to fluorinate silicon and germanium in a heated Knudsen cell in a mass spectrometer. Second‐ and third‐law calculations using effusion data for the gaseous monofluoride and difluoride species produced at temperatures up to 1575°K are in good agreement and lead to the following atomization energies: D°₂₉₈[SiF(g)]=5.61±0.2 eV, ΔH°_a,298[SiF₂(g)]=12.33±0.2 eV, D°₂₉₈[GeF(g)]=5.04±0.2 eV, and ΔH°_a,298[GeF₂(g)]=10.0±0.8 eV.