Thermodynamic study of tin sulfide and lead sulfide using a mass spectrometer

Abstract

A mass-spectrometric investigation of the vapor in equilibrium with solid SnS, solid PbS, and a mixture of SnS and PbS has yielded the following reaction enthalpies: SnS(s)→SnS(g) ΔH2980 = 52.6±1.6 kcal/mole 2SnS(s)→Sn2S2(g) 56.5±5.0 PbS(s)→PbS(g) 55.7±1.6 2PbS(s)→Pb 2S2(g) 66.6±5.0 PbS(g)→Pb(g) + 1/2 S 2(g) 28.8±2.6 Sn2S2(g)→2SnS(g) 48.7±5.0 Pb2S2(g)→2PbS(g) 44.8±5.0 SnPbS2(g)→SnS(g)+PbS(g) 46.5±5.0. The dissociation energies of gaseous SnS and PbS were determined to be D00 (SnS) = 110.1±3.0 kcal/mole, D00(PbS) = 79.1±2.8 kcal/mole and are compared with the spectroscopically determined values.