Phase equilibria and thermodynamic properties of saturated solid solutions based on the compounds BiSeI, Bi19Se27I3, and BiI3 in the Ag-Bi-Se-I system

摘要

We have studied phase relations in the AgI-BiI3-Se-Bi2Se3 region of the Ag-Bi-Se-I system for T a parts per thousand currency sign 530 K and derived equations of overall potential-forming reactions involving the phases BiSeI, Bi19Se27I3, and BiI3. The reactions were brought about in electrochemical cells of the form C |Ag| Ag3GeS3I glass |D| C (where C stands for an inert (graphite) electrode, Ag and D denote the electrodes of the cell, D is a mechanical mixture of four phases in the system under investigation, and Ag3GeS3I glass is a membrane with purely ionic (Ag+) conductivity). The linear temperature dependences of EMF for the cells in the range 485-510 K were used to calculate the standard thermodynamic functions of the compounds BiSeI, Bi19Se27I3, and BiI3.