THERMODYNAMICALLY STABLE PHASES OF THE Ag9GaSe6 – Ag8GeSe6 SYSTEM AT T

The synthesis of thermodynamically stable phases of the Ag9GaSe6–Ag8GeSe6 (І) system at T<600 K were performed in the electrochemi­cal cells (ECCs): (−) С | Ag | SЕ | R(Ag+) | PЕ |&...

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Date:2022
Main Authors: Moroz, Mykola, Demchenko, Pavlo, Prohorenko, Myroslava, Soliak, Ludmila, Prohorenko, Serhii, Reshetnyak, Oleksandr
Format: Article
Language:English
Published: V.I.Vernadsky Institute of General and Inorganic Chemistry 2022
Online Access:https://ucj.org.ua/index.php/journal/article/view/449
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Journal Title:Ukrainian Chemistry Journal

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Ukrainian Chemistry Journal
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author Moroz, Mykola
Demchenko, Pavlo
Prohorenko, Myroslava
Soliak, Ludmila
Prohorenko, Serhii
Reshetnyak, Oleksandr
author_facet Moroz, Mykola
Demchenko, Pavlo
Prohorenko, Myroslava
Soliak, Ludmila
Prohorenko, Serhii
Reshetnyak, Oleksandr
author_sort Moroz, Mykola
baseUrl_str
collection OJS
datestamp_date 2022-08-16T11:52:47Z
description The synthesis of thermodynamically stable phases of the Ag9GaSe6–Ag8GeSe6 (І) system at T<600 K were performed in the electrochemi­cal cells (ECCs): (−) С | Ag | SЕ | R(Ag+) | PЕ | С (+), where C is graphite, Ag is the left (negative) electrode, SE is the purely Ag+ ion conducting solid electrolyte (Ag2GeS3-glass), PE is the right (positive) electrode, and R(Ag+) is the region of PE that contact with SE. PEs of ECCs were prepared from finely ground non-equilibrium mixtures of the compounds (Ag9GaSe6)1–х and (Ag8GeSe6)х, х=0.05, 0.1, 0.2, … , 0.9. Shifted from the left electrode to the R(Ag+) region for thermodynamic reasons Ag+ ions acted as the nucleation centers for the equilibrium phases of the x compositions, that is as the catalysts for reconstruction of the metastable mixtures of ternary compounds. The reproducibility of the EMF vs T dependences in the heating-cooling cycles is a result of the completion of reconstruction in the R(Ag+) region. Experimental dependences EMF vs T of ECCs with PE of mixtures of compounds indicated x, ECCs with PE of the Ag9GaSe6 and Ag8GeSe6 compounds are charac­terized by several discrete linear regions with different temperature intervals and functional dependences on temperature. The equations of the temperature dependences of the partial Gibbs energies of Ag-component in alloys for each discrete section of the specific x=0, 0.3, 0.5, 0.7, 1.0 were established for the first time and values of the standard partial functions  were calculated. The bypass lines drawn through the points of EMF values of the cells at T=const for arbitrarily selected temperatures 298 K, 341 K, 395 K, 445 K, and 495 K in the range 280-500 K determine the phase composition of the equilibrium T-x space of (I) as: a solid solution based on compound Ag17GaGeSe12 in the range of 0.25≤x≤0.75, solid solutions based on the compounds (Ag9GaSe6)1–х for 0≤х≤0.15 and (Ag8GeSe6)х for 0.83≤х≤1, and two two-phase sections in the ranges 0.15≤x≤0.25 and 0.73≤x≤0.77. Some parameters of the crystal structure, the values of the total and ionic components of conductivity, the transfer numbers in the range of 290–380 K, and the integral va­lues of the standard thermodynamic functions of the Ag17GaGeSe12 compound were established for the first time.
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spelling oai:ojs2.1444248.nisspano.web.hosting-test.net:article-4492022-08-16T11:52:47Z THERMODYNAMICALLY STABLE PHASES OF THE Ag9GaSe6 – Ag8GeSe6 SYSTEM AT T Moroz, Mykola Demchenko, Pavlo Prohorenko, Myroslava Soliak, Ludmila Prohorenko, Serhii Reshetnyak, Oleksandr Ag-containing compounds, Thermodynamic properties, Phase equilibria, Metastable state, EMF method. The synthesis of thermodynamically stable phases of the Ag9GaSe6–Ag8GeSe6 (І) system at T<600 K were performed in the electrochemi­cal cells (ECCs): (−) С | Ag | SЕ | R(Ag+) | PЕ | С (+), where C is graphite, Ag is the left (negative) electrode, SE is the purely Ag+ ion conducting solid electrolyte (Ag2GeS3-glass), PE is the right (positive) electrode, and R(Ag+) is the region of PE that contact with SE. PEs of ECCs were prepared from finely ground non-equilibrium mixtures of the compounds (Ag9GaSe6)1–х and (Ag8GeSe6)х, х=0.05, 0.1, 0.2, … , 0.9. Shifted from the left electrode to the R(Ag+) region for thermodynamic reasons Ag+ ions acted as the nucleation centers for the equilibrium phases of the x compositions, that is as the catalysts for reconstruction of the metastable mixtures of ternary compounds. The reproducibility of the EMF vs T dependences in the heating-cooling cycles is a result of the completion of reconstruction in the R(Ag+) region. Experimental dependences EMF vs T of ECCs with PE of mixtures of compounds indicated x, ECCs with PE of the Ag9GaSe6 and Ag8GeSe6 compounds are charac­terized by several discrete linear regions with different temperature intervals and functional dependences on temperature. The equations of the temperature dependences of the partial Gibbs energies of Ag-component in alloys for each discrete section of the specific x=0, 0.3, 0.5, 0.7, 1.0 were established for the first time and values of the standard partial functions  were calculated. The bypass lines drawn through the points of EMF values of the cells at T=const for arbitrarily selected temperatures 298 K, 341 K, 395 K, 445 K, and 495 K in the range 280-500 K determine the phase composition of the equilibrium T-x space of (I) as: a solid solution based on compound Ag17GaGeSe12 in the range of 0.25≤x≤0.75, solid solutions based on the compounds (Ag9GaSe6)1–х for 0≤х≤0.15 and (Ag8GeSe6)х for 0.83≤х≤1, and two two-phase sections in the ranges 0.15≤x≤0.25 and 0.73≤x≤0.77. Some parameters of the crystal structure, the values of the total and ionic components of conductivity, the transfer numbers in the range of 290–380 K, and the integral va­lues of the standard thermodynamic functions of the Ag17GaGeSe12 compound were established for the first time. V.I.Vernadsky Institute of General and Inorganic Chemistry 2022-06-24 Article Article Physical chemistry Физическая xимия Фізична xімія application/pdf https://ucj.org.ua/index.php/journal/article/view/449 10.33609/2708-129X.88.05.2022.25-36 Ukrainian Chemistry Journal; Vol. 88 No. 5 (2022): Ukrainian Chemistry Journal; 25-36 Украинский химический журнал; Том 88 № 5 (2022): Ukrainian Chemistry Journal; 25-36 Український хімічний журнал; Том 88 № 5 (2022): Український хімічний журнал; 25-36 2708-129X 2708-1281 en https://ucj.org.ua/index.php/journal/article/view/449/227
spellingShingle Moroz, Mykola
Demchenko, Pavlo
Prohorenko, Myroslava
Soliak, Ludmila
Prohorenko, Serhii
Reshetnyak, Oleksandr
THERMODYNAMICALLY STABLE PHASES OF THE Ag9GaSe6 – Ag8GeSe6 SYSTEM AT T
title THERMODYNAMICALLY STABLE PHASES OF THE Ag9GaSe6 – Ag8GeSe6 SYSTEM AT T
title_full THERMODYNAMICALLY STABLE PHASES OF THE Ag9GaSe6 – Ag8GeSe6 SYSTEM AT T
title_fullStr THERMODYNAMICALLY STABLE PHASES OF THE Ag9GaSe6 – Ag8GeSe6 SYSTEM AT T
title_full_unstemmed THERMODYNAMICALLY STABLE PHASES OF THE Ag9GaSe6 – Ag8GeSe6 SYSTEM AT T
title_short THERMODYNAMICALLY STABLE PHASES OF THE Ag9GaSe6 – Ag8GeSe6 SYSTEM AT T
title_sort thermodynamically stable phases of the ag9gase6 – ag8gese6 system at t
topic_facet Ag-containing compounds
Thermodynamic properties
Phase equilibria
Metastable state
EMF method.
url https://ucj.org.ua/index.php/journal/article/view/449
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AT soliakludmila thermodynamicallystablephasesoftheag9gase6ag8gese6systematt
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