Aqueous phase stability of multinary thiostannates

This research proposes a comprehensive study of the thermodynamic stability of the structurally similar Cu–Fe–Zn–Sn–S multinary sulfides, critical materials that are pivotal in advancing semiconductor technologies. In light of the scarcity of thermodynamic data in the extant literature concerning a relevant number of mineral phases, the missing data were estimated using a method based on the sum of molecular fragments. Consequently, a novel numerical extrapolation method derived from experimental thermochemical stability constants is integrated with the simulation capabilities of the PHREEQC software. This integration facilitates the meticulous charting (using the formalism of Pourbaix diagrams) of the stability domains of Cu–Fe–Zn–Sn–S multinary sulfides in aqueous environments. The present analysis addresses a critical knowledge gap regarding the aqueous stability of multinary sulfides, while introducing a robust theoretical framework for predicting their environmental and technological viability. This objective is accomplished by delineating the relative stability and precipitation boundaries of the studied phases, thereby providing invaluable insights for the development of these sustainable semiconducting materials. Consequently, this research makes two significant contributions. Firstly, it contributes to the theoretical understanding of multinary sulfide systems. Secondly, it establishes the foundation for their practical application in green technologies.