Thermodynamics of AgCl + Ag 2S and AgBr + Ag 2S melts by mass spectrometry

Abstract

The activities of AgX (where X = Cl or Br) in molten mixtures of AgX and Ag 2S were determined by mass spectrometry using the monomer to trimer ion-current ratio technique. Both systems exhibited positive deviations from ideality. Both melts were found to be regular over the entire composition range. The characteristic parameter w for the two mixtures was found to vary linearly with temperature. For AgCl plus Ag 2S in the liquid range, the excess Gibbs energy can be represented, between 850 and 1050 K, by the following equation: G E = X 1X 2{(5660 ± 130) - (3.02 ± 0.02)(T/K)} cal th mol−1 Similarly for AgBr plus Ag 2S, between 850 and 975 K, G E = X 1X 2 {(3590 ± 90) - (0.45 ± 0.02)(T/K)} cal th mol−1