Experimental investigation of the Ag–Bi–I ternary system and thermodynamic properties of the ternary phases

Highlights: ► The self-consistent phase diagram of the Ag–Bi–I system is constructed. ► Ag2BiI5 and AgBi2I7 are the only ternary phases of the system. ► Standard thermodynamic functions of formation and the standard entropies of Ag2BiI5 and AgBi2I7 are calculated. - Abstract: The phase equilibriums in the Ag–Bi–I ternary system and thermodynamic properties of the ternary phases were experimentally determined by using DTA and XRD techniques and EMF measurements with the Ag4RbI5 solid electrolyte. According to the obtained experimental results, the polythermal sections of the ternary phase diagram, its isothermal section at 300 K as well as the projection of the liquids surface have been revised. The fields of the primary crystallization and types and coordinates of nonvariant and monovariant equilibriums were determined. The partial molar functions of silver iodide and silver in the alloys as well as the standard thermodynamic functions of formation and the standard entropies of Ag2BiI5 and AgBi2I7 were calculated based on EMF measurements.