Determination of the thermodynamic properties of the Ag2CdSn3S8 and Ag2CdSnS4 phases in the Ag–Cd–Sn–S system by the solid-state electrochemical cell method

Triangulation of the quaternary Ag–Cd–Sn–S system in the Ag₂SnS₃–SnS–Sn₂S₃–CdSpart below T = 600 K wasperformed using X-ray diffraction method. The spatial position of the determined four-phase regions regarding the figurative point of silver was used to write forming chemical reactions. Theforming reactions were performed by applying electrochemical cells (ECCs):(–) C | Ag | Ag₂GeS₃ glass | Ag₂CdSn₃S₈,SnS, Sn₂S₃, CdS | C (+)and (–) C | Ag | Ag₂GeS₃ glass | Ag₂CdSnS₄, SnS, Ag₂CdSn₃S₈,CdS | C (+), where C is graphite andAg₂GeS₃ glass is the fast purely Ag⁺ ionsconducting electrolyte. The linear dependencies of the EMF of the ECCs ontemperature in the range T = (462–500) Kwere used to calculate the standard thermodynamic values of the Ag₂CdSn₃S₈ and Ag₂CdSnS₄phases for the first time.