Solid-liquid phase equilibria in the fullerenol-d-CuCl2-H2O system at 25°C

Solubility in the ternary fullerenol-d-CuCl₂-H₂O system at 25°C is studied by means of isothermal saturation in ampoules. It is established that the diagram consists of two branches corresponding to the crystallization of fullerenol-d crystallohydrate and copper(II) chloride dihydrate and contains a single non-variant eutonic point corresponding to the reciprocal saturation with both solid phases. The salting-in effect on the crystallization branch of CuCl₂ · 2H₂O and the salting-out effect on the crystallization branch of fullerenol-d is revealed.     

Solvation of cations in the LiNO3-Ca(NO3)2-H2O system at 25°C. A molecular dynamics simulation study

A series of solutions of the ternary LiNO₃-Ca(NO₃)₂-H₂O system is simulated under standard conditions by means of classical molecular dynamics (MD). Several variants of the potentials of interparticle interactions predicting different structures and compositions of the lithium cation hydration shell are used in the calculations. The coordination numbers of ions, the mean residence times of water molecules and nitrate anions in the solvation shells of cations, and the self-diffusion coefficients of solution components are estimated for all of the investigated systems. The structural features of the solvation shells of cations in multicomponent aqueous solutions are described on the basis of the obtained data.     

Phase formation in the ZrO(NO3)2-NaF(HF)-H3PO4-H2O system at 20°C

Phase formation in the ZrO(NO₃)₂-NaF(HF)-H₃PO₄-H₂O system was studied at 20°C and 2.0–14.5 wt % ZrO₂ in the initial solution along sections with molar ratios PO ₄ ^3? /Zr = 0.5 and 1.5 and also in the presence of hydrogen fluoride at Na/Zr = 1 and PO ₄ ^3? /Zr = 0.5, 1.0, and 1.5. Crystalline zirconium hydrophosphate Zr(HPO₄)₂ · H₂O, fluorozirconates Na₅Zr₂F₁₃ and Na₇Zr₆F₃₁ · 12H₂O, fluorophosphatozirconates NaH₂Zr₃F₃(PO₄)₄ · 3H₂O and NaZr₂F₆(PO₄) · 4H₂O, and amorphous NaZrO_0.5F(PO₄) · 4H₂O (provisional composition) were separated at room temperature. NaH₂Zr₃F₃(PO₄)₄ · 3H₂O and NaZr₂F₆(PO₄) · 4H₂O were prepared for the first time and were studied by crystal-optical, elemental, and thermal analyses, X-ray powder diffraction, IR spectroscopy, scanning electron microscopy (SEM), and X-ray microanalysis. Na₇Hf₆F₃₁ · 12H₂O was found to exist in a mixture with the hydrophosphate.     

Study of the system Pr2O3-SeO2-H2O at 100°C and the properties of the compounds obtained

The solubility of the system Pr₂O₃-SeO₂-H₂O at 100°C was studied. The fields of crystallization of Pr₂(SeO₃)₃·H₂O, PrH(SeO₃)₂, Pr(HSeO₃)₃ were established. The compounds obtained were identified by means of chemical, X-ray and thermal analysis. The thermal decomposition of Pr₂(SeO₃)₃·H₂O, PrH(SeO₃)₂, and Pr(HSeO₃)₃ was determined.This revised version was published online in November 2005 with corrections to the Cover Date.     

Löslichkeitsdiagramm des Systems CaPHO3-H3PO3-H2O bei 25°C

Zusammenfassung Das System CaPHO₃-H₃PO₃-H₂O wurde zum ersten Male mittels der Löslichkeitsmethode untersucht. Aus dem Löslichkeitsdiagramm wurde festgestellt, daß sich im System drei kongruent lösliche Verbindungen, das Calciumhydrogenphosphitmonohydrat CaH₂(PHO₃)₂·H₂O und die Additionsverbindungen CaH₂(PHO₃)₂·H₃PO₃ und 2 CaH₂(PHO₃)₂·H₃PO₃, bilden. Von diesen Salzen wurden bisher die beiden letzteren noch nicht in der Literatur beschrieben. Auf Grund des Löslichkeitsdiagramms wurden diese beiden Phosphite als weiße, kristalline, in Wasser gut lösliche Substanzen rein dargestellt.Mit 1 Abbildung     

La(CCl3COO)3-La(ClO4)3-H2O system at 25°C

The lanthanum trichloroacetate-lanthanum perchlorate-water ternary system was studied by the isothermal solubility method at 25°C. The compositions of solid phases were studied by the Schreinemakers method. The refraction indices, specific volumes, and viscosities of liquid phases were determined. The crystallization of the initial components and, the formation of a closed area of solid solutions were established in the system.     

Thermodynamical study of the zinc selenate-cobalt selenate-water system at 25°C

Summary The solubility in the ZnSeO₄-CoSeO₄-H₂O system has been studied at 25°C. It has been established that the CoSeO₄·6H₂O monoclinic crystal structure is unstable and undergoes a change into a tetragonal structure due to the included zinc ions. Activity coefficients of the salt components in the saturated solutions and in the mixed crystal hexahydrates have been determined by the isopiestic method. G ^F of (Zn_xCo_1–x)SeO₄·6H₂O mixed crystals shows a negative deviation from ideality.

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Thermodynamische Untersuchung des Systems Zinkselenat-Kobaltselenat-Wasser bei 25°C

Zusammenfassung Die Löslichkeitsisotherme des Systems ZnSeO₄-CoSeO₄-H₂O wurde bei 25°C untersucht. Es wird festgestellt, daß das monokline CoSeO₄·6H₂O unstabil ist und in tetragonale Mischkristalle übergeht. Mittels der isopiestischen Methode wurden die Aktivitätskoeffizienten der Komponenten in den gesättigten Dreistofflösungen und Mischkristallen bestimmt. G ^F der Mischkristallbildung weist eine negative Abweichung vom idealen Zustand auf.

     

Prediction of the solubility of HCl-MgCl2-H2O system at −5°C using the ion-interaction model

The component solubilities of the HCl-MgCl₂-H₂O system at −5°C were predicted by using the Pitzer ion interaction model and its extended Harvie and Weare model. The results indicated that the model supplies a good prediction of the above-mentioned system. The values of parameters of β⁽⁰⁾, β⁽¹⁾, and C ^φ of HCl and MgCl₂ were obtained by using the same optimization methods as in the literature, while those of θ_MgH and Ψ_MgHCl were derived by extrapolating the published data of 5, 15, 25, 35, and 45°C, as well as coupling the activity coefficients with the solubility data. The comparison between the calculated results and the experimental data indicated that the Pitzer ion interaction model and its extended Harvie and Weare model are quite reliable in the solubility prediction. The text was submitted by the authors in English     

NH4VO3在NH4H2PO4-H2O和(NH4)3PO4-H2O体系中的溶解度

采用等温溶解法测定了偏钒酸铵(NH₄VO₃)在NH₄H₂PO₄-H₂O和(NH₄)₃PO₄-H₂O体系中T = 298.15-328.15 K时的溶解度以及溶液的密度和pH值。结果表明, NH₄VO₃的溶解度随着(NH₄)₃PO₄或NH₄H₂PO₄溶液浓度的增大,先降低后升高,这是由于同离子效应、化学反应平衡及离子活度的共同作用。比较T = 298.15K时, NH₄VO₃分别在NH₄H₂PO₄-H₂O、(NH₄)₂HPO₄-H₂O和(NH₄)₃PO₄-H₂O体系中溶解度,发现在相同的磷酸盐浓度下, NH₄VO₃的溶解度在NH₄H₂PO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在(NH₄)₂HPO₄-H₂O体系中最小。进一步地,在T = 298.15 K和磷酸盐浓度C = 0.5 mol·kg^-1时,结合pH值和反应溶度积常数K_SP等计算三个体系中的平均离子活度系数(γ_±),发现γ_±值在(NH₄)₂HPO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在NH₄H₂PO₄-H₂O体系中最小,与溶解度规律一致。     

Phase formation along the PO 4 3− /Zr = 1.5–2.0 section of the ZrO(NO3)2-KF-H3PO4-H2O) system

The phase composition of precipitates at 20°C along the PO ₄ ^3? /Zr = 1.5–2.0 section at KF/Zr = 1–5 (mol/mol) of the ZrO(NO₃)₂-H₃PO₄-KF-H₂O system has been investigated. Phases in these precipitates have been identified by X-ray powder diffraction, crystal-optical, chemical, and thermal analyses and by IR spectroscopy. The previously known potassium zirconates K₃ZrF₇ and K₂ZrF₆ have been revealed, and crystalline fluorophosphate zirconate K₃Zr₃F₃(HPO₄)₃(PO₄)₂ and a phosphate nitrate of unknown formula have been obtained for the first time.     

Diffusion coefficients of the system α-cyclodextrin-n-butylurea-water at 25°C

Diffusion coefficients were measured for the ternary system -cyclodextrin(I)-n-butylurea(2)-water at three average concentrations. The cross coefficient D₁₂ was found to be almost zero and D₂₁ large and negative. These results are in agreement with the presence of an inclusion complex whose mobility is close to that of the host cyclodextrin molecules. The values of the four experimental diffusion coefficients are used to compute a value of the inclusion constant which is in reasonably good agreement with the calorimetric value.     

Liquid-solid equilibrium for the NaCl-NaHCO3-Na2CO3-H2O system at 45°C. Validation of mixed solvent electrolyte model

The main objective of this work was to verify the mixed solvent electrolyte (MSE) thermodynamic model for the prediction of the liquid-solid equilibrium in the soda system. The full quaternary system NaCl-NaHCO₃-Na₂CO₃-H₂O and its three subsystems were considered. Validation of the thermodynamic model was based on experimental data from literature. Phase diagrams for the soda system are plotted for isotherms of 45°C. Good agreement of the MSE results with those from experiments was found at 45°C. Similar phase diagrams for other temperature levels can be constructed based on the validated MSE model.     

Activity measurements in the ternary system NaBr+NaClO4+H2O at 25°C

The activity coefficients of sodium bromide in the ternary system NaBr+NaClO₄+H₂O were determined at 25°C and constant ionic strength of 0.1, 0.5, 1, 2, and 3 mol-kg^?1 from emf of the cell without, liquid junction $$ISE - Na|NaBr(m_A ), NaClO_4 (m_B ), AgCl_{(s)} 1 Ag$$ The experimental activity coefficients were comparatively analyzed by using the Harned, Scatchard, Pitzer and Lim-HOLL treatments. All these methods are adequate for the analysis of the experimental data. The results have been compared with those of Lanier for the system: NaCl+NaClO₄+H₂O. The Gibbs excess energy of mixing was obtained and qualitatively interpreted in terms of ionic interactions.     

Comparative analysis of the solubility in the systems CuBr2-NR4Br-H2O at 25°C

The solubility in the CuBr₂-NR₄Br-H₂O (R = Me, Et, n-Bu) ternary systems at 25°C was determined by the isothermal saturation method. Comparative analysis of the phase equilibria diagrams was done. The results obtained were interpreted in terms of the competition of two processes, association of tetraalkylammonium salts and copper(II) complex formation in water-salt systems.     

Solubility in the LaCl3-YbCl3-HCl-H2O System at 25°C

Solubility has been studied in the LaCl₃-YbCl₃-HCl-H₂O water-salt system at 25°C along the (40 ± 0.2)% HCl section; this is a eutonic-type system. The composition of the eutonic solution is as follows (wt %): LaCl₃ · 7H₂O, 4.67, YbCl₃ · 6H₂O, 0.37; HCl, 37.98; and H₂O, 56.98.     

Solubility in the ZnCl2-CO(NH2)2-HCl-H2O system at 25°C

The ZnCl₂-CO(NH₂)₂-HCl-H₂O quaternary system at 25°C was studied by the solubility method. The concentration boundaries of crystallization were established for the phases that correspond to the eutonic compositions of ternary systems, for double carbamide compounds with zinc chloride and hydrochloric acid, and for the compound ZnCl₂ · 2CO(NH₂)₂ · HCl.