- The phase equilibria in the Tl-S-I system and electrical properties of the Tl6SI4 and TlS compounds
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The phase equilibria in the ternary Tl-S-I system were investigated experimentally by means of powder X-ray diffraction (PXRD) and differential thermal analysis (DTA). Five isopleth sections, liquidus surface projection and room temperature isothermal sec
- Babanly, Dunya M.,Aliev, Ziya S.,Huseynov, Qorkhmaz M.,Asadov, Salim M.,Mustafaeva, Solmaz N.,Tagiyev, Dilgam B.
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- Phase diagram of the Tl-TlI-S system and thermodynamic properties of the compound Tl6SI4
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Phase equilibria in the Tl-TlI-S composition region of the Tl-S-I system were studied by dif- ferential thermal analysis, x-ray powder diffraction, and measurements of the microhardness and the emf of concentration circuits relative to a thallium electrode. A series of polythermal sections, an isothermal section at 300 K, and a projection of the liquidus surface were constructed. Primary crystallization regions of six phases, including the ternary compounds Tl6SI4 and Tl3SI, were outlined, and the types and coordinates of non- and monovariant equilibria were determined. It was shown that the ternary compound Tl6SI4 forms tie lines with Tl, TlI, Tl2S, Tl4S3, and TlS in the subsolidus region and that the homogeneity region of Tl6SI4 below 400 K does not exceed 1 mol %. From the emf measurement data, the standard thermodynamic functions of formation and standard entropy of the compound Tl6SI4 were calculated: ΔG0 f,298;= -601.7 ± 2.5 kJ/mol, ΔH0 f,298;= -595.1 ± 4.0 kJ/mol, and S0298 = 672 ± 10 J/(mol K). Pleiades Publishing, Ltd., 2012.
- Babanly,Guseinov,Babanly,Sadygov
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- Liquid ammonia mediated metathesis: Synthesis of binary metal chalcogenides and pnictides
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Addition of stoichiometric amounts of low valent metal halides to liquid ammonia solutions of disodium chalcogenide (Na2E; E = S, Se, Te) afforded a range of both crystalline (PbE (E = S, Se, Te), TIE (E = S, Se), Tl5Te3, Ag2E (E = S, Se, Te)) and X-ray amorphous (MS (M = Ni, Cu, Zn, Cd, Hg), M2E3 (M = Ga, In; E = S, Se, Te), HgE (E = Se, Te), CuE (E = S, Se, Te), Cu2S) metal chalcogenides in good yield (95%). Reactions between metal halides and sodium pnictides (Na3Pn; Pn = As, Sb) in liquid ammonia also afforded X-ray amorphous material (M3Pn2, M = Zn, Cd; MPn, M = Fe, Co, Ni) in good yield (95%). Isolation of the metal chalcogenides and pnictides was achieved through washing with CS2 and distilled water. All reactions were complete within 36 h. Products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDXA), electron probe analysis, FR-IR spectroscopy, Raman spectroscopy, microanalysis, and band gap measurements. Annealing amorphous material at 250-300 °C for 48 h induced sufficient crystallinity for analysis by X-ray powder diffraction.
- Shaw,Parkin
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p. 6940 - 6947
(2008/10/08)
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- Tl4Re6X12 (X = S, Se): Crystal growth, structure, and properties
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Single crystals of two new phases Tl4Re6S12 and Tl4Re6Se12 isostructural with (Rb,K)4Re6Se12 were synthesized by high-temperature reaction of TlX, Re, and X (X = S, Se). The structure of the selenide was solved by single-crystal X-ray investigation (space group C2/c, R = 0.08). The structure consists of Re6Se8 cluster units interconnected three-dimensionally by four Se and two Se2 bridges. Tl4Re6S12 is isostructural with Tl4Re6Se12. The cell parameters of Tl4Re6S12 and Tl4Re6Se12 are a = 16.653 (2) ?, b = 9.574 (3) ?, c = 11.816 (8) ?, β = 90.62 (2)° and a = 17.177 (3) ?, b = 9.846 (2) ?, c = 12.195 (2) ?, β = 90.71 (2)°, respectively. Z = 4 for both compounds. Physical measurements show that these compounds are semiconducting and diamagnetic, which is consistent with 24 electrons per cluster unit filling the valence band. Bond-order calculations of Tl4Re6Se12 and other related compounds indicate a Re-Re bond order of 1 in all of the known Re6X8 cluster compounds.
- Huan,Greaney,Tsai,Greenblatt
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p. 2448 - 2451
(2008/10/08)
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