Schwingungsspektren der Schwefelringe S8, 34S8, S12 und S12 · CS2 sowie thermodynamische Funktionen der Moleküle Sn (n = 2 — 12) / Vibrational Spectra of the Sulfur Rings S8, 34S8, S12 and S12 · CS2 and Thermodynamic Functions of the Molecules Sn (n = 2…12)

Abstract

Raman spectra of S8, 34S8, S12, and S12 · CS2 are reported and force constants have been calculated for S8 and S12 using a modified Urey-Bradley force field. The fundamental vibrations and molecular geometries of S8 and S12 have been used for the calculation of thermodynamic functions. The standard entropies, S0 T, as well as the molar heat capacities, Cp, of sulfur species Sn are shown to depend linearly on the molecular size, n, as follows (in J · mole-1 · K-1): S0 298 = 35.16n + 147.0, Cp(298 K) = 21.00 n - 11.7. By interpolation entropies for S9, S10 and S11 have been obtained, and these data are used to show that the concentrations of sulfur rings larger than S8 in sulfur vapor must be negligibly small.