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[en] The crystal monohydrate of thorium selenite Th(SeO₃)₂.H₂O was obtained by the Th(IV) precipitation selenious acid from water solution. The yield of the mentioned compound in regard to Th (IV) was up to 100 %. The identity of the compound was proved by the methods of X-Ray phase analysis and derivatography. The process of synthesized thorium selenite monohydrate dehydration was studied by the vapour pressure method. The values of enthalpy and entropy of the dehydration process are ΔH_T⁰ = 92.9 ± 2.1 kJ.mol^-1 and ΔS_T⁰ = 187.9 ± 3.8 J.mol^-1, respectively. On the basis of the value of dehydration enthalpy and calculated standard enthalpy of anhydrous thorium selenite formation Δ_fH⁰ (Th(SeO₃)_2(cr); 298 K), the value Δ_fH^o (Th(SeO₃)₂.H₂O _(cr); 298 K) was obtained, which was found to be -2082.4 ± 8 kJ.mol^-1. (author)

[en] The degree of ionicity of bonds in oxochlorides and oxobromides of trivalent metals (MeOHal) has been calculated. The derived values have been compared with some physicochemical parameters of Me³⁺ ions, MeO molecules, and molecular MeO⁺ ions. A satisfactory correlation has been established between the polarizing capacity of the Me³⁺ cation and bonding ionicity in oxohalides

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[en] Standard formation enthalpies of boron, silicon and phosphorus are calculated. For calculations thermochemical method in conjunction with potential energy model of oxoanions in approximation of valence-force field of molecules and crystals are used. In the model of valence-force field ion-covalent crystals are considered as population of clusters of molecular type the number of which is equal to number of translation-nonequivalent atoms in the lattice dipped in nonhomogeneous electrostatic field of long-range interactions. For gaseous oxoanions field created by end oxygen atoms or other ones on which negative charge of anions is localized serves as equivalent of nonhomogeneous electrostatic field. In such approach potential energy of oxoanion is equal to sum of energy of electrostatic repulsion of negatively charged atoms and energy of valent element-oxygen bonds in neutral cluster

[en] The system MeCl-(La,Y)OCl (Me=Li,Na,K,Rb,Cs) and MeCl-ErOCl (Me=Li,Rb,Cs) have been studied by the methods of differential-thermal and X-ray phase analyses. The system NaCl-LaOCl has been studied by cryoscopic method as well. It has been established that the systems refer to the type of fusibility diagrams with a simple eutectics. A comparison of the fusibility diagrams with calculations for ideal systems, under the assumption that the association degree of ions is different, makes it possible to assume a considerable polymerizations degree of oxychloride in the melts MeCl-(Y,Er)OCl

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[en] The structure of thin ZrO₂ films synthesized on silicon substrates to create a buffer layer for further deposition of high-temperature superconductor films, is investigated. It is ascertained that Y⁺³ addition facilitates the formation of zirconium dioxide cubic modification with the degree of film texturing exceeding 95%. The films obtained are resistant to high temperatures (up to 1000 deg C) and stable in time

[en] This work is devoted to research relating to the development of new thin film barrier coatings, the associated preparation technique, and their use for solving various scientific and engineering problems associated with the improvement of the performance of low level waste disposal facilities. The work presents the main results of zirconium dioxide thin film coatings preparation process by organometallic composite solutions on various substrates and bases with subsequent thermal treatment at 400-1000 deg. C. Experimental work on the formation of isolating corrosion-resistant ZrO₂ (Y₂O₃) coatings over different substrates and bases, including microporous ones, indicate potential applications of the technology to coating barrier materials such as quartz, sand, concrete, alumina