Experimental study of phase equilibria and thermodynamic properties of the Tl–Se–I system
- 49 Downloads
The phase equilibria in the ternary Tl–Se–I system have been investigated by means of differential thermal analysis, X-ray powder diffraction and the electromotive force measurements (EMF) of electrochemical cells relative to the thallium electrode with ionic liquid as an electrolyte. Several polythermal sections, the isothermal section at 300 K and the projection of the liquidus surface of the system have been constructed. The homogeneity and primary crystallization regions of intermediate phases, as well as types and coordinates of non- and monovariant equilibria have been determined. Formation of two congruently melting ternary compounds (Tl5Se2I at 720 K, and Tl6SeI4 at 705 K) was observed. It was revealed that the system is characterized by the existence of wide areas of α- (based on Tl2Se) and δ-solid solutions (based on Tl5Se2I). Standard thermodynamic functions of formation and standard entropies of Tl5Se2I and Tl6SeI4 compounds were calculated based on the thermodynamic study of Tl–Se–I alloys by the EMF measurements with an ionic liquid electrolyte.
KeywordsThallium selenide–iodides Tl5Se2I Tl6SeI4 Solid solutions Phase diagram Thermodynamic properties
- 24.Peresh EYU, Lazarev VB, Kornejchuk OI, Semrad EE. Phase equilibria in Tl2S (Se, Te)-TlI and TlSe-TlCl(Br, I) systems. Inorg Mater. 1999;29(3):440–5.Google Scholar
- 25.Peresh EYU, Lazarev VB, Chigica VV, Kornejchuk OI. Homogeneity regions, preparation and properties of Tl6SI4, Tl5Se2Br(I) monocrystals. Russ J Inorg Chem. 1991;27(10):2079–85.Google Scholar
- 28.Babanly DM, Huseynov GM, Huseynova RG, Mustafayeva AL. Physico-chemical interaction of thallium iodides with sulfur. Kimya Problemleri—Chem Probl. 2015;2:154–5 (ISSN 2221-8688).Google Scholar
- 29.Babanly DM, Aliyev ASH. Physico-chemical aspects of obtaining new phases of variable composition on the basis of thallium tellurium-halides. Kimya Problemleri—Chem Probl. 2016;1:26–35 (ISSN 2221-8688).Google Scholar
- 31.Babanly DM, Babanly MB. Phase equilibria in the Tl-TlBr-Te system and thermodynamic properties of the compound Tl5Te2Br. Russ J Inorg Chem. 2010;55(3):1442–7.Google Scholar
- 35.Wagner K. Thermodynamics of alloys. Moscow: M: Metallurgizdat; 1957.Google Scholar
- 36.Morachevskii AG, Voronin GF, Kutsenok IB. Electrochemical research methods in thermodynamics of metallic systems. Moscow: ITSK “Akademkniga”; 2003.Google Scholar
- 37.Massalski TB, editor. Binary alloy phase diagrams. 2nd ed. Materials park: ASM International; 1990.Google Scholar
- 38.Vasil’yev VP, Nikol’skaya AV, Gerasimov YI. Thermodynamic investigation of the alloys in the system thallium-selenium system by EMF method. Russ J Phys Chem. 1971;45(8):2061–3.Google Scholar
- 39.Iorish VS, Yungman VS, editors. Data Base of Thermal Constants of Substances; 2006. Digital version. http://chem.msu.ru/cgi-bin/tkv.