Phase relations in the condensed Se-S system

No thermodynamic data characterising the mixed Se Sg phases have been identified in the literature, except for some enthalpies of fusion presented in [78LAI/NII]. 

Bocter and Kullerud [87BOC/KUL] also studied Se-S melts, and found no evidence of liquid immiscibility. They found, however, that the temperature for polymerisation in the melt significantly decreased, and could principally be described by an equilibrium copolymerisation model [84KEN/WHE], The only explicit thermodynamic datum available is the enthalpy of mixing, which was studied by Maekawa, Yokokawa and Niwa [73MAE/YOK] at 620 and 730 K. Data were collected in the range of 0.15 xse 0.85 and could, at both temperatures, be described by the equation  

From molecular parameters presented in [87F1N/KRU], the heat capacity expression 

The molecular parameters were also used to calculate the selected standard entropy of SeS(g)  

The present review selects the data in [77DRO/SMO]. A third law evaluation using these data results in  

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Figure V-11 Phase relations in the condensed Se-S system. Reprinted from [87BOC/KUL], Copyright (1987), with permission from Elsevier.

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