O. N. Pestova

X-ray diffraction study of isomorphous crystal nonahydrates of aluminum, gallium, and scandium perchlorates

Crystal structures of isomorphous crystal nonahydrates of aluminum, gallium, and scandium perchlorates were determined by the X-ray crystal analysis at room temperature. The estimate of associates present in concentrated solutions was carried out by the method of X-ray diffraction in aqueous solutions of aluminum perchlorate.

Solubility of d-element salts in organic and aqueous–organic solvents: II. Effect of halocomplex formation on solubility of cobalt bromide and chloride and nickel chloride

Solubility of salts in the systems MCl2–H2O–Solv (M = Co, Ni) and CoBr2–H2O–Solv (Solv = dimethyl sulfoxide, dimethyl formamide, and dimethyl acetamide) at 25°C was measured experimentally. Dominating species of cobalt and nickel halides existing in various concentration regions were identified by analysis of electron absorption spectra. It was shown that the major factor defining solubility is the interaction of halocomplexes of metal ions with solvent molecules.

Solubility of aluminum, gallium, and indium perchlorates in water

Solubility polytherms of the system M(ClO4)3-H2O (M3+ = Al3+, Ga3+, In3+) were measured. Positions of singular points and vitrification ranges were determined. Values of eutectic concentrations were compared with earlier known data on the inversion concentrations measured by the viscometry method. Compositions of found crystalline hydrates were calculated from the solubility polytherms. The concept of the ability of the studied aqua cations to show properties of aqua acids, of the structure of solutions of posteutectic concentrations (structurally forced processes and microheterogeneity), of the electronic structure of M3+ cations, and of the localized hydrolysis phenomenon were used to understand the existence of the polyaqua compounds.

Structural microheterogeneites in strontium perchlorate solutions of posteutectic concentrations

Aqueous solutions of strontium perchlorate were studied in a wide range of concentrations at room temperature by X-ray diffraction, thermogravimetry, and calorimetry. The features of the solubility polytherm of strontium perchlorate, that distinguish it from those of other Group II metal perchlorates, were explained in terms of two coexisting interconverting crystal hydrates.

Formation of binary salts in the system LiCl–CsCl–H2O

In the ternary system LiCl–CsCl–H2O the binary salt LiCl·2CsCl·4H2O was formed. Its structure was proved by the X-ray structural analysis. The binary compound formed in the aqueous solution by the structurally-forced insertion mechanism.

Energy Characteristics of Lithium–Cesium Binary Chloride Dissolution in Water

Enthalpies of dissolution of the binary salt LiCl·3CsCl·4H2O and dry mixtures of lithium and cesium chlorides in the molar ratio 1: 3 were measured by the calorimetry method. The value of the mutual influence of ions in solution was determined, and the enthalpy of the binary salt formation from the individual components was calculated.

Solubility polytherms and eutectic concentrations of scandium, yttrium, and lanthanum perchlorate solutions

Freezing points of solutions M(ClO4)3-H2O (M = Sc, Y, La) of different concentrations were determined. The solubility polytherms of the perchlorate systems studied, as well as aluminum, gallium, and indium perchlorates were compared with the concentration dependences of different properties of the corresponding solutions. Viscometry and IR spectroscopy allowed the special points on these dependences to be correlated with eutectic concentrations. Structural changes in the systems studied as a function of solute concentration were described.