Equilibrium Composition of Sulfur Vapor

Abstract

Sulfur vapor, as well as the vapors in equilibrium with solid HgS, CdS, ZnS, FeS, SrS, and CaS have been studied mass‐spectrometrically. The results indicate the presence of all possible S n molecules between S2 and S8 in measurable concentration between room temperature and the boiling point of sulfur. Negligible concentrations of S9 and S10 are also observed. The high‐temperature experiments are most concordant with the ``high'' value of D 0(S2), about 4.4 eV. For the reactions (n/8)S8→S n (n=2, 3, 4, 5, 6, 7), the enthalpy changes at ∼400°K are ΔH 2=23.5 kcal/mole, ΔH 3=22.5 kcal/mole, ΔH 4=20.5 kcal/mole, ΔH 5=14.3 kcal/mole, ΔH 6=6.2 kcal/mole, and ΔH 7=5.7 kcal/mole.