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-CdS part below T = 600 K was performed 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. The forming 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 and Ag2GeS3 glass is the fast purely Ag+ ions conducting electrolyte. The linear dependencies of the EMF of the ECCs on temperature in the range T = (462-500) K were used to calculate the standard thermodynamic values of the Ag2CdSn3S8 and Ag2CdSnS4 phases for the first time.