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The volatile Fe(dpm)₃ complex was studied by X-ray diffraction at 243 K and 210 K. A phase transition from monoclinic to triclinic structure was found in the temperature range 236-226 K. The packing of complexes in the structures is analyzed by the procedure of translation sublattice isolation. The motif of mutual arrangement of Fe atoms is pseudohexagonal in both modifications. Apart from the differences in the Fe…Fe distances, there are differences in rotation of definite chelate rings.

[RhPy₄Cl₂]₄[Re₆S₈(CN)₆]⋅1.5H₂O (Py is pyridine) was investigated by X-ray analysis. In the cluster anion, the Re-Re distances vary from 2.6063(2) Å to 2.6125(2) Å. For two crystallographically independent complex cations, the distances are 〈Rh-N〉 2.060 Å and 〈Rh-Cl〉 2.336 Å. The motif of the three-layered close packing was found; the [Re₆S₈(CN)₆]^4- anions follow the vertices of a rhombohedron with the parameters a_c ≈ 15.5 Å and α_c ≈ 61°.

The crystal and molecular structure of 1-phenyl-1-fluoro-5-methylquasisilatrane PhFSi(OCH₂CH₂)₂NMe was investigated by X-ray diffraction at 100 K. The coordination polyhedron of the silicon atom in the molecule is a slightly distorted trigonal bipyramid containing fluorine and nitrogen atoms in the axial positions and two endocyclic oxygen atoms and the carbon atom of the phenyl group at three vertices of the equatorial plane.

The products obtained from the Pt_0.25Os_0.75 nonequilibrium solid solution treated by the thermobaric procedure (1.5-2 GPa, 2000°C, 3 min) were investigated by X-ray powder diffraction. The phase compositions were evaluated from quantitative X-ray phase analysis, energy dispersion spectroscopy, and crystal-chemical analysis data for known Pt_хOs_1-х phases.

The many-electron wave function is represented as the product of the wave function of the independent particles and the function that depends only on the value of the interelectron interaction potential. The function defines the electron correlation effects; a standard linear differential equation was derived to define the function. The equation depends on the functions of independent particles; a generalization of the Hartree-Fock equations including electron correlation was obtained for these functions. The total energy calculation of two-electron ions shows that even solving an ordinary differential equation for the function of independent particles represented by the functions of noninteracting electrons leads to higher accuracy than the one achieved in the Hartree-Fock theory.

This paper reports on our quantum-chemical analysis of the nucleophilic substitution of the bromine atom by the cyano group in the reaction of methylbromoacetylene with copper cyanide. According to calculations, the reaction can form a four-membered ring containing a copper atom.

Density functional theory (B3LYP/6-31G*) is applied to calculate structures, energy, dipole moment, polarizability, frequencies of normal vibrations in the harmonic approximation and intensities in vibrational spectra of 2-, 3-, and 4-biphenylmethanol molecules and their H-complexes that can form in crystalline, amorphous, and liquid phases. Based on the analysis of simulation results, the effect of the position of a methanol group in the molecule on its vibrational spectrum is discussed. The structure forming role of a hydrogen bonds in biphenylmethanols and the possibility of realization of two polymorphic modifications in 2-biphenylmethanol are stated. These modifications are: metastable monoclinic, in which each of four molecules of the unit cell is a link of a chain Н-associate; and stable triclinic, in which four molecules of the unit cell organize an Н-complex in the form of a cyclic tetramer. It is found that crystalline samples of 3- and 4-biphenylmethanols consist of chain Н-associates. A glass-like sample of 2BPhM being a mixture of Н-complexes consisting of cyclic tetramers and chain associates contains crystalline nuclei of triclinic and monoclinic polymorphous modifications in the supercooled state. In a liquid sample of 2BPhm, chain Н-associates and free molecules are realized.

The division algorithm for additive and multiplicative noise components of the electron scattering intensity is proposed in the work. The procedure presented provides a substantial improvement in experimental data processing in comparison with the traditional method used by Russian research groups. A comparison of the additive noise with the simulated residual gas scattering shows that it is this scattering that is largely responsible for the strange contribution to the measured diffraction pattern.

This work presents a way to select the optimal form of the sector lobe and practical algorithms to determine the sector function of the device in use. Knowledge of the sector function enhances the quality of drawing a background line and ensures the division of multiplicative and additive noise components, thus increasing the reliability of structural parameters determined by gas electron diffraction.
Keywords: gas electron diffraction, sector function, background line.

Samples of synthetic high-silica zeolites after high-temperature activation in oxygen are studied by ferromagnetic resonance. Observation of the fine structure of ferromagnetic resonance (FMR FS) indicates the formation of magnetic iron oxide nanoparticles in the course of thermal treatment of zeolites in oxygen. Features of the formation of a dispersed ferromagnetic phase in zeolites, geometric and magnetic characteristics of constituent nanoparticles are discussed.
Keywords: zeolites, thermal oxygen treatment, ferromagnetic nanoparticles, ferromagnetic resonance.