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The article presents the results of EPR studies of Pb₂MoO₅ crystals containing a copper impurity. Based on the analysis of angular dependences of the EPR spectra, it is found that copper ions incorporate into the structure of the Pb₂MoO₅ crystal in the Cu²⁺ state and occupy the molybdenum site with the formation of a linear extended Cu(II)-V(O)-Pb(IV) defect along the а axis of the crystal. An oxygen vacancy appears in the structure of the defect to compensate the charge and the lead ion acquires the Pb⁴⁺ charge state. According to the structure of this center, one magnetically non-equivalent position with the direction of main values of А and g of A (Cu) _zz and g_zz tensors parallel to the а axis is observed in the EPR spectra. Moreover, the EPR spectra exhibit an addition hyperfine structure from one lead atom on which the unpaired electron density is 0.061 %. The obtained data on the structure of the defect formed when the copper impurity incorporates into the Pb₂MoO₅ crystal provided the assumption that the observed light scattering when the light beam is directed perpendicular to the а axis may be due to the cooperative effect of the presence of di- and tetravalent ions substituting for molybdenum in the linear configuration of Pb-O-Mo bonds.

Hexagonal boron nitride films are synthesized by plasma enhanced chemical vapor deposition (PECVD) from a gas mixture of borazine and ammonia or helium on a Si(100) substrate. X-ray photoelectron spectroscopy is used to study changes in the electronic structure and chemical composition of the films depending on the composition of the initial gas mixture. It is found that the chemical composition of the samples obtained depends on the gas used. The use of helium results in an excess of boron atoms on the film surface, the appearance of B-B bonds, and a decrease in the contribution of B-N bonds in the hexagonal environment. The preparation of h-BN films close to the stoichiometric composition by PECVD methods with the use of borazine is shown to be possible with the addition of ammonia. Based on the literature data, the binding energies in the B 1 s spectra are calculated for different boron environments in the hexagonal lattice.

A new potassium cadmium hydrogen diphosphate dihydrate, KCdHP₂O₇×2H₂O (1), has been synthesized by slow evaporation at room temperature and characterized by FT-IR, Raman, TG-DTA, and single crystal X-ray diffraction. Compound (1) crystallizes in the orthorhombic Pcmn space group with the unit cell parameters a = 6.5814(8) Å, b = 7.9428(9) Å, c = 15.961(6) Å, V = 834.4(3) ų and Z = 4. Its structure consists of polyhedral layers parallel to the ab plane where each CdO₆ octahedron ( m position) shares four edges with three different diphosphate groups. In the Cd octahedron, two oxygen atoms residing in ( m ) special positions belong to coordinated water molecules. These layers are joint by K⁺ cations (4 c Wyckoff position) and hydrogen bonds, leading thus to a two-dimensional framework. The structural model is supported by the bond-valence-sum validation tool as calculated valences are close to the formal oxidation numbers.

The optimal configurations and the vibrational spectra of heteroassociates (HA) of hydrogen fluoride and diethylketone molecules with 1:1, 2:2, 4:1, and 8:2 compositions are calculated using the density functional theory (B3LYP/6-31++G(d,p)). A comparison of the results of calculations and the known experimental data reveal that the following stable hydrogen-bonded molecular complexes are formed in HF-Et₂CO solutions: the C_2h-symmetry cyclic heterotetramer (HF)₂×(Et₂CO)₂ and the tricyclic HA (HF)₈×(Et₂CO)₂ formed based on the heterotetramer by the binding of two (HF)₃ moieties. It is shown that it is appropriate to decompose the spectral curve into the Gaussian functions or the Lorentzian functions to determine the frequencies and the integrated intensities of broad and overlapped IR bands. The first type of the decomposition enables one to estimate more correctly the values of the band frequencies, and the second type makes it possible to find more correctly the band intensities.

Dissolution heats of L-alanine in aqueous NaCl ( m ≤ 5 mol/kg water) and KCl ( m ≤ 4 mol/kg water) solutions are measured by the calorimetric method at temperatures of 288 K, 298 K, and 313 K. Enthalpic and heat capacity coefficients of the pair and triple interaction of alanine with non-aqueous components are determined. By means of the literature data the contributions of charged COO^- groups and hydrocarbon radicals of (СНСН_{3 of} L- alanine and СН₂ of glycine) in water mixtures with NaCl, KCl, and urea are found. The effects of the nature of additives and temperature on the interactions of hydrophilic and hydrophobic groups of the amino acids in the mentioned systems are discussed.

The organization principles of crystal structures of a series of fluoridoborates with large cations and their topological analogues are considered based on the current cation framework representations. Outer-framework anionic components are differentiated into leading (template) and subordinate with respect to their structure directing function.

Changes in the crystal structure, which are accompanied by iron intercalation and release in a layered intercalate TiSe₂ compound demonstrating retrograde solubility in the complete solid state are considered. Various concentration regions not exceeding, exceeding, and corresponding to the leakage limit of the overlap of titanium orbitals coordinated by iron are analyzed. It is shown that at low temperatures (below 400 С) the behavior of iron in the TiSe₂ lattice is governed by a covalent bond of iron with the lattice whereas at high temperatures (above 1000 С) iron becomes an ionic impurity. In the intermediate temperature range, iron atoms are involved in either covalent or ionic bond with the lattice. When the concentration of iron in the form of the ionic impurity increases, an increase in the cell parameter in the direction perpendicular to the layers is accompanied by a compression of the Se-Ti-Se sandwich and an increase in the van der Waals gap. When the covalent bond forms, there is a decrease in the lattice parameter in the direction perpendicular to the layers, which is accompanied by an increase in the width of the Se-Ti-Se sandwich and a decrease in the van der Waals gap.

Three new salts of the {[Ca(H₂O)]₆[P₄W₆O₃₄]₂}^12- polyanion, namely (NH₄)₁₂{[Ca(H₂O)]₆××[P₄W₆O₃₄]₂}×24H₂O (1), H₂[Na(H₂O)_1.6]₁₀{[Ca(H₂O)]₆[P₄W₆O₃₄]₂}×10H₂O (2), and [Ca(H₂O)₅]₆{[Ca(H₂O)]₆[P₄W₆O₃₄]₂}×11H₂O (3) are prepared. The change in the lattice as a function of the countercation and its coordination, specially calcium, is investigated. Full characterization is made by single crystal X-ray diffraction and also UV-visible spectroscopy, FT-IR, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS).

The monoclinic modification of complex [Cu(NH₃)₄](ReO₄)₂ salt is studied by single crystal X-ray diffraction in the range of 100-410 K. Crystallographic data at 300 K are as follows: a = 10.6123(3) Å, b = 7.5443(2) Å, c = 15.2261(4) Å, b = 108.406(1)°, V = 1156,67(5) ų, space group Р 2₁/ n , Z = 4, d _x = 3.623 g/cm³. The coordination environment of the Cu atom is a distorted square formed by four nitrogen atoms; Cu-N of 1.997-2.018 Å; supplemented with contacts with two oxygen atoms Cu…О 2.472 Å and 2.598 Å. A comparative crystallochemical analysis with the triclinic modification of [Cu(NH₃)₄](ReO₄)₂ known in the literature is performed.

The μ-oxo-bridged Fe(III) dimer complex [{Fe(4-MeOL1)}₂(m-O)]×HOCH₃, (H₂-4-MeOL1 = N , N '-bis(4-methoxy-2-hydroxybenzylidene)-2,2-dimethylpropane-1,3-diamine), 1 is synthesized and characterized by single crystal X-ray diffraction. Complex 1 contains a [{Fe(4-MeOL1)}₂(μ-O)] dimeric unit with a methanol solvent molecule of crystallization. Each Fe(III) ion has a distorted square-pyramidal coordination geometry. In the basal plane, the Fe(III) atom is coordinated by two N and two O atoms of the Schiff base ligand. The apical position is occupied by a bridging O^2- ion, linking another Fe(III) ion in the complex. There are intermolecular C-H⋯O and C-H⋯π interactions among the dinuclear complexes.