Thermodynamic Properties of Superionic Phase Ag4HgSe2I2 Determined by the EMF Method

Triangulationof the Ag-Hg-Se-I system in the vicinity of quaternaryphase Ag₄HgSe₂I₂ was performed by differentialthermal analysis, X-ray diffraction and electromotive force (EMF) methods. The spatial position of the phase region Ag₄HgSe₂I₂-Se-HgI₂regarding the figurative pointof silver was used to write the chemical reaction of formation of Ag₄HgSe₂I₂. The EMF measurements were carried out by applying an electrochemical cell: (–) C | Ag | Ag₂GeS₃ glass | Ag₄HgSe₂I₂,HgI₂, Se | C (+), where C is graphite and Ag₂GeS₃ glassis the fast purely Ag⁺ ions conducting electrolyte. The lineardependence of the EMF of the electrochemical cell on temperature was used to determinethe standard thermodynamic values of Ag₄HgSe₂I₂ forthe first time.