Interactions and glass formation in the TlAs2Se4-Tl3As2Se3Te3 system

The TlAs₂Se₄-Tl₃As₂Se₃Te₃ system was studied using differential thermal analysis (DTA), powder X-ray diffraction, microstructure observation, and microhardness and density measurements. A phase diagram of the title system was constructed. This system is a quasi-binary join of the TlSe-As₂Se₃-As₂Te₃ quasi-ternary system. All alloys of the system under standard conditions are prepared in the glassy form. The system has a eutectic, which contains 50 mol % Tl₃As₂Se₃Te₃ and melts at 150°C. The TlAs₂Se₄-base solid solution in the system extends to 12 mol % Tl₃As₂Se₃Te₃, and Tl₃As₂Se₃Te₃-based solid solution extends to 20 mol % TlAs₂Se₄.     

Phase equilibria and glass formation in the As2S3-TlAs2S2Se2 section of the As2S3-As2Se3-TlS system

Alloys in the As₂S₃-TlAs₂S₂Se₂ section of the As₂S₃-As₂Se₃-TlS ternary system were studied and a phase diagram was constructed using physicochemical methods (differential thermal analysis, microstructural analysis, X-ray powder diffraction, also microhardness and density measurements). The diagram in the As₂S₃-TlAs₂S₂Se₂ section is a non-quasi-binary diagonal section of the As₂S₃-As₂Se₃-TlSe quasi-ternary system. It was found that all the alloys in the section under ordinary conditions are obtained in the vitreous state. At low As₂S₃ concentrations in the section, solid solutions form up to 2.5 mol %, and at low TlAs₂S₂Se₂ concentrations, their extent is 3 mol %.     

Phase diagram of the In3As2Se6-In3As2S3Se3 system

The In₃As₂Se₆-In₃As₂S₃Se₃ system has been investigated by methods of physicochemical analysis (DTA, X-ray powder diffraction, MSA) and by microhardness and density measurements. The phase diagram of the system, which is the quasi-binary section of the As-In-S-Se quaternary system, has been constructed. The region of the In₃As₂Se₆-based solid solutions is extended to 7 mol %, and the In ₃As₂S₃Se₃-based region to 15 mol %. A new quaternary compound In₆As₄S₃Se₉ is found in the system. Original Russian Text ? I.I. Aliev, R.S. Magammedragimova, A.A. Farzaliev, Dzh. Veliev, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 4, pp. 691–694.     

Phase equilibrium in the As2S3-TlSe system

The interaction between the components of the As₂S₃-TlSe system has been studied using diffeential thermal analysis, powder X-ray diffraction, microstructure examination, and microhardness and density measurements. Two new quaternary compounds, TlAs₂S₃Se and Tl₃As₂S₃Se₃, are formed in the system. Both compounds may be prepared in a glassy state. They melt congruently at 350 and 280°C, respectively. The section As₂S₃-TlSe is a stable diagonal of the ternary reciprocal system As,Tl ‖ S, Se. The As₂S₃-base solid solution extends to 1.5 mol % TlSe. The extent of the TlSe-base solution is 5.2 mol % As₂S₃. Under slow cooling, the glass field in the system extends to 85 mol % TlSe; when the system is quenched to liquid nitrogen, the extent of the glass field is 100 mol % TlSe.     

Synthesis of complex sulfide phases BaSm<Subscript>2</Subscript>S<Subscript>4</Subscript>-Tm<Subscript>2</Subscript>S<Subscript>3</Subscript> and studies of their electrolytic properties

The possibility of synthesizing complex sulfide phases in the BaSm₂S₄-Tm₂S₃ system has been studied. Tm₂S₃ solid solutions were obtained with BaSm₂S₄ (CaFe₂O₄ structural type). The samples were identified by X-ray diffraction analysis and electron microscopy. The range of the solid solutions was determined. The total conductance was studied, and the conductance activation energy was calculated for samples with different dopant contents. The electrolytic properties of basic ternary sulfide and complex sulfide phases in the BaSm₂S₄-x mol % Tm₂S₃ system were investigated. A possible mechanism of defect formation was proposed.     

Interaction of components in the Tl<Subscript>2</Subscript>Se-Tl<Subscript>4</Subscript>SnSe<Subscript>4</Subscript>-Tl<Subscript>9</Subscript>SbSe<Subscript>6</Subscript> quasi-ternary system

The interaction in the Tl₂Se-Tl₄SnSe₄-Tl₉SbSe₆ quasi-ternary system was studied by differential thermal analysis, X-ray powder diffraction analysis, and mathematical modeling. The projection of the liquidus surface and a spatial phase diagram of the system were constructed. It was determined that this system is of the eutectic type with boundary solid solutions based on the initial components. No formation of new intermediate compounds in the quasi-ternary system was detected.     

MnS-Pr<Subscript>2</Subscript>S<Subscript>3</Subscript> phase diagram

The MnS-Pr₂S₃ phase diagram is of the eutectic type with incomplete solubility based on the starting sulfides (MnS and Pr₂S₃). The extent of the MnS-based solid solution at 1470 K is 1 mol % Pr₂S₃. γ-Pr₂S₃ at 1470 K dissolves 23 mol % MnS, α-Pr₂S₃ at 1170 K dissolves 6 mol % MnS. The eutectic composition (30 mol % Pr₂S₃ at 1550 K) coincides with the value calculated from the Schroeder equation for the liquidus branch descending from MnS. A value of 64 kJ/mol was calculated for the heat of melting of Pr₂S₃ using the Schroeder equation.     

Phase equilibria in the PbSe-Bi<Subscript>2</Subscript>Se<Subscript>3</Subscript>-Se system and thermodynamic properties of intermediate phases

The Pb-Bi-Se system in the PbSe-Bi₂Se₃-Se-Se composition region was studied by measurement of concentration circuits of the type (−) PbSe(solid) liquid electrolyte, Pb²⁺(Pb-Bi-Se)(solid) (+) in the temperature range 300–430 K and by X-ray powder diffraction. A solid-phase equilibrium diagram was constructed, and the formation was confirmed for the ternary compounds Pb₅Bi₆Se₁₄, Pb₅Bi₁₂Se₂₃, and Pb₅Bi₁₈Se₃₂, which belong to the homologous series [(PbSe)₅] _m · [(Bi₂Se₃)₃] _n . From the emf versus temperature equations, the partial thermodynamic functions [`(DG)]\overline {\Delta G}, [`(DH)]\overline {\Delta H}, [`(DS)]\overline {\Delta S} of PbSe in alloys were calculated. Based on the solid-phase equilibrium diagram from these partial molar quantities using the corresponding data for PbSe and Bi₂Se₃, the standard thermodynamic functions of formation and standard entropies of the above ternary compounds were calculated.     

Phase diagrams of the systems Sc<Subscript>2</Subscript>S<Subscript>3</Subscript>-Ln<Subscript>2</Subscript>S<Subscript>3</Subscript> for Ln = La,Nd, or Gd

Phase diagrams have been designed for the systems Sc₂S₃-Ln₂S₃ where Ln = La, Nd, or Gd. In these systems, complex sulfides crystallize in orthorhombic space group Pnma. The sulfides melt congruently and have the following parameters; for LaScS₃, a = 0.718 nm, b = 0.654 nm, c = 0.960 nm, 2000 K, 3200 MPa; for NdScS₃, a = 0.712 nm, b = 0.646 nm, c = 0.952 nm, 1960 K, 3500 MPa; and for GdScS₃, a = 0.704 nm, b = 0.640 nm, c = 0.946 nm, 1900 K, 3400 MPa. The extents of the solid solutions based on the existing phases increase as the effective ion radii of Ln³⁺ approaches that of Sc³⁺. At 1670 K, the LnScS₃ homogeneity region is 48–52 mol % Nd₂S₃ and 46–54 mol % Gd₂S₃. Sc₂S₃ dissolves 3 mol % Nd₂S₃ and 6 mol % Gd₂S₃. γ-Nd₂S₃ dissolves 2 mol % Sc₂S₃, and γ-Gd₂S₃ dissolves 4 mol % Sc₂S₃. The subsystems Sc₂S₃-LnScS₃ and LnScS₃-Ln₂S₃ are of the eutectic type. The eutectic coordinates are, respectively, 27 mol % La₂S₃, 1880 K; 75 mol % La₂S₃, 1800 K; 30 mol % Nd₂S₃, 1850 K; 74 mol % Nd₂S₃, 1770 K; 33 mol % Gd₂S₃, 1800 K; and 74 mol % Gd₂S₃, 1730 K.     

The 3Ga<Subscript>2</Subscript>S<Subscript>3</Subscript>-EuLaGa<Subscript>3</Subscript>S<Subscript>7</Subscript> system

The La₂S₃-Ga₂S₃-EuS system has been investigated along the 3Ga₂S₃-EuLaGa₃S₇ join by physicochemical methods (DTA, X-ray powder diffraction, microstructural analysis). is a quasi-binary eutectic-type section of the ternary system. Solubility on the base of both components has been revealed in the system. Solubility at room temperature is 3 mol % EuLaGa₃S₇ on the Ga₂S₃ side 1.5 mol % Ga₂S₃ and on the base of the EuLaGa₃S₇ compound. The coordinates of the eutectic point are 80 mol% EuLaGa₃S₇ and 1020 K.     

Phase equilibria in the BaS-Cu<Subscript>2</Subscript>S-Gd<Subscript>2</Subscript>S<Subscript>3</Subscript> system

Phase equilibria in the BaS-Cu₂S-Gd₂S₃ system have been studied along the 800 K isothermal section and the CuGdS₂-BaS, Cu₂S-BaGdCuS₃, BaGdCuS₃-Gd₂S₃, and BaGdCuS₃-BaGd₂S₄ polythermal sections. Complex sulfide BaGdCuS₃ is formed in the title system; it has an orthorhombic KZrCuSe₃-type structure (space group Cmcm) with the unit cell parameters equal to a = 0.40529(2) nm, b = 1.34831(6) nm, c = 1.02940(5) nm. This sulfide melts congruently at 1685 K. BaGdCuS₃ is in equilibrium with sulfides Cu₂S, BaS, Gd₂S₃, CuGdS₂, BaGd₂S₄, BaCu₄S₃, and BaCu₂S₂ and with compositions in the C₀ solid-solution region of the Cu₂S-Gd₂S₃ system. Eutectics are formed between compounds CuGdS₂ and BaGdCuS₃ at 7.0 mol % BaS and T = 1325 K, between BaGdCuS₃ and BaS at 64.0 mol % BaS and T = 1625 K, between Cu₂S and BaGdCuS₃ at 8.0 mol % BaGdCuS₃ and T = 1125 K, between Gd₂S₃ and BaGdCuS₃ at 64.0 mol % Gd₂S₃ and 1495 K, and between BaGdCuS₃ and BaGd₂S₄ at 35 mol % BaGd₂S₄ and T = 1660 K.     

Some properties of rhodium thioselenochloride RhCl<Subscript>4</Subscript>Se<Subscript>6</Subscript>S<Subscript>9</Subscript> and its thermal conversion products

The structure of rhodium thioselenochloride RhCl₄Se₆S₉ and the products of its thermal decomposition are studied by X-ray photoelectron and IR spectroscopies, X-ray powder diffraction, thermal, and elemental analyses. The thermal decomposition of RhCl₄Se₆S₉ was found to occur with a loss of weakly bonded chloro-, sulfur-, and selenium-containing fragments (at 100°C); at the higher temperatures, chlorine is lost and rhodium thioselenides are obtained (Rh₄Se₄S₅ at 490°C and Rh₄Se₃S₅ at 665°C). These changes are attended by the formation of the cluster nucleus [Rh₄(µ_3-Se)₃(µ₃-S)].Translated from Koordinatsionnaya Khimiya, Vol. 30, No. 12, 2004, pp. 910–914.Original Russian Text Copyright © 2004 by Pekhno, Stepanenko, Volkov, Fokina, Korduban.     

Electrochemical properties of solid electrolytes based on BaSm<Subscript>2</Subscript>S<Subscript>4</Subscript>

Solid solutions based on BaSm₂S_{4 ? x} mol % BaS (Sm₂S₃) are obtained. Oxide intermediates were homogenized using chemical and mechanical mixing methods. The solid solution region is determined. Complex conductivity is studied and conductivity activation energy is calculated for samples with different history. Electrolytic properties of phases based on barium thiosamarate are studied. Vacancy mechanism of defect formation is suggested.     

Sm<Subscript>2</Subscript>S<Subscript>3</Subscript>-Sm<Subscript>2</Subscript>O<Subscript>3</Subscript> phase diagram

The Sm₂S₃-Sm₂O₃ phase diagram was studied by physicochemical methods of analysis from 800 K up to melting. Two oxysulfides are formed in the system: Sm₁₀S₁₄O with tetragonal crystal structure (space group I41/acd; unit cell parameters: a = 1.4860 nm, c = 1.9740 nm; microhardness: H = 4700 MPa; solid decomposition temperature: 1500 K) and Sm₂O₂S with hexagonal structure (space group P-3m1; a = 0.3893 nm, c = 0.6717 nm; H = 4500 MPa; congruent melting temperature: 2370 K). Within the extent of the Sm₂O₂S-based solid solution (61–70 mol % Sm₂O₃) at 1070 K, a singular point appears at the compound composition on property-composition curves. The eutectic coordinates: 23 mol % Sm₂O₃ and 1850 K; 80 mol % Sm₂O₃ and 2290 K.     

Mechanism of photoinduced nanodimensional expansion/contraction in glassy thin layers of As<Subscript>2</Subscript>S<Subscript>3</Subscript>

The mechanism of photoinduced expansion/contraction in glassy As₂S₃ has a photochemical nature. Photostructural transformation is connected with rearrangement of As₄S₄ molecules and similar non-stoichiometric compounds, As₄S_4+x. These molecules are believed to exist in clusters which correspond to the second glass-forming region of As–S systems, including the As₅₆S₄₄ eutectic. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 45, No. 1, pp. 59–63, January–February, 2009.     

Osmium thioselenochloride Os<Subscript>2</Subscript>S<Subscript>6</Subscript>Se<Subscript>2</Subscript>Cl<Subscript>8</Subscript>: Synthesis,cluster isolation,and structure

The quaternary thioselenochloride complex Os₂S₆Se₂Cl₈ (I) was obtained by a reaction of OsO₄ with a solution of Se in S₂Cl₂ at 100°C and identified by combination of X-ray diffraction (polycrystalline approach) and cluster framework isolation. A reaction of complex I with melted 4-cyanopyridine (4-CNPy) at 165°C gave the complex Os₂S₂Cl₄(4-CNPy)₄, which confirms the integrity of the binuclear cluster frame-work [Cl₂OsS₂OsCl₂] in complex I.     

Tl2S-Sb2S3-Bi2S3 quasi-ternary system

The Tl₂S-Sb₂S₃-Bi₂S₃ quasi-ternary system (system A) was studied using DTA, X- ray powder diffraction, microstructure examination, and microhardness measurements. TlSbS₂-Tl₄Bi₂S₅(TlBiS₂, Bi₂S₃), Sb₂S₃-TlBiS₂, Tl₃SbS₃-TlBiS₂(Bi₂S₃), and [TlSb_0.5Bi_0.5S₂]-Tl₂S isopleths; isothermal sections at 500 K; and liquidus surface projection of system A were constructed. Characteristic features of the title system are extensive fields of solid solutions extended along the TlSbS₂-TlBiS₂ quasi-binary section and a continuous solubility belt 1–2 mol % wide extended along the Sb₂S₃-Bi₂S₃ binary subsystem. Primary separation fields of phases and the types and coordinates of invariant and monovariant equilibria in system A were determined.     

Reactivity of triangular oxalate cluster complexes [M<Subscript>3</Subscript>Q<Subscript>7</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>3</Subscript>]<Superscript>2−</Superscript> (M = Mo or W; Q = S or Se)

The reactions of the oxalate complexes [M₃Q₇(C₂O₄)₃]²⁻ (M = Mo or W; Q = S or Se) with Mn^II, Co^II, Ni^II, and Cu^II aqua and ethylenediamine complexes in aqueous and aqueous ethanolic solutions were studied. The previously unknown heterometallic complexes [Mo₃Se₇(C₂O₄)₃Ni(H₂O)₅]·3.5H₂O (1) and K₃{[Cu(en)₂H₂O]([Mo₃S₇(ox)₃]₂Br)}·5.5H₂O (2) were synthesized. In these complexes, the oxalate clusters serve as monodentate ligands. The K(H₂en)₂[W₃S₇(C₂O₄)₃]₂Br·4H₂O salt (3) was isolated from solutions containing Co^II, Ni^II, or Cu^II aqua complexes and ethylenediamine. The reaction of [Mo₃Se₇(C₂O₄)₃]²⁻ with HBr produced the bromide complex [Mo₃Se₇Br₆]²⁻, which was isolated as (Bu₄N)₂[Mo₃Se₇Br₆] (4). Complexes 1–3 were characterized by X-ray diffraction, IR spectra, and elemental analysis. The formation of 4 was detected by electrospray mass spectrometry. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1645–1649, September, 2007.     

Chemical conversions of rhodium selenochloride Rh<Subscript>2</Subscript>Se<Subscript>9</Subscript>Cl<Subscript>6</Subscript>

Rhodium selenochloride Rh₂Se₉Cl₆ (1) reacts with aqueous solutions of KCN and CsCl and 4-cyanopyridine (4-CNPy) to give complexes KCs₂Rh(CN)₆ (2) and RhCl₃(4-CNPy)₃ (3). According to X-ray diffraction data, 2 and 3 have mononuclear structures in which the rhodium atoms are in the oxidation state III and six-coordinate environment. Reactions 1 with CN-containing ligands lead to complete displacement of selenium-containing ligands from the rhodium coordination sphere.     

Ternary reciprocal systems Na,K||BO<Subscript>2</Subscript>,CO<Subscript>3</Subscript> and Na,K||BO<Subscript>2</Subscript>,Cl

The phase diagrams of the ternary reciprocal systems Na,K||BO₂,CO₃ and Na,K||BO₂,Cl were studied for the first time by a calculation-experimental method and by differential thermal analysis. Analytical models of phase equilibrium states were derived, and the coordinates of eutectics were found to be (680°C, 32 mol % NaBO₂, 68 mol % KCl) and (648°C, 9 mol % NaBO₂, 45.5 mol % NaCl, 45.5 mol % KCl). Binary solid solutions based on metaborates and carbonates of sodium and potassium were shown to be stable. The possibility of synthesizing tungsten oxide bronzes in a eutectic melt in the ternary system NaBO₂–NaCl–КCl was revealed.