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Magmatism of the Uda sector enclosed within the West Transbaikalian rift zone (WTRZ) is discussed in this paper. Seven stages of the Late Mesozoic-Cenozoic volcanism have been recognized within span 174-51 Ma. On the border about 135 Ma the nature of volcanism changed noticeably: (a) the volume of volcanic rocks essentially reduced; (b) transition from differentiated to basaltic associations proceeded with the disappearance of volcanics containing SiO2 over 54 wt.%; (c) alkali and subalkaline basaltoids appeared in the associations, their volume increasing at later stages. Geochemical features of the Uda volcanics are determined by participation in their formation of the mantle source close in composition to the source with OIB parameters. They are responsible for high concentrations of incompatible elements in magmatic products. The isotope characteristics of rocks indicate conformity of this mantle source to the varying behavior of EMII and PREMA with the role of the latter strengthening in time. The basaltoids of initial stages show the deficit of Ti, Nb, and Ta caused by involvement of water-saturated lithosphere mantle in magma formation. The main specifics of the Uda volcanics composition and the pattern of their variability in time correspond to those in WTRZ, as well as in the other Late Mesozoic-Cenozoic rift zones of Central Asia. This evidence suggests similar geodynamic settings for origination and development of rifting processes, when continuously evolving mantle plume affects the regional lithosphere. The magmatism of the Uda sector, as in the entire WTRZ, differs considerably from magmatic processes developing over the convergent boundaries of the Mongol-Okhotsk belt; their products are represented by differentiated magmatic associations with geochemical properties are common for the rocks of suprasubduction zones.

Structures and relative energies of binuclear iron-manganese complexes with the phosphine ligand L, which exist in vinylidene Cp(CO)(L)MnFe(m-C=CHPh)(CO)₄ (2) and benzylidene ketene h⁴-{C[Mn(CO)(L)Cp]××(CO)CHPh}Fe(CO)₃ (3) forms are calculated by the B3LYP density functional method. Four isomers with different positions of ligand L relative to the phenyl ring (conformers a and b) and the substituent Ph relative to the С=С bond (conformers E and Z) are considered for each form and their relative stability is determined. It is shown that all isomers of 2 have approximately the same energy (within 4 kcal/mol) whereas the energies of isomers of 3 differ within 21 kcal/mol. Isomer 3Ea in which the PPh₃ ligand contacts with the phenyl substituent of the vinylidene group is most energetically favorable. It is found that with an increase in the L ligand size in the order PH₃ < PH₂Ph < PHPh₂ < PPh₃ the Mn-P bond length increases to 2.37 Å in the most stable isomer of form 3 and to 2.43 Å in the isomers of 2 and three conformers of 3. A more substantial increase in the Mn-P bond length in complexes 2 and 3 correlates with their lower stability as compared to isomer Ea of 3, which is consistent with experimental data on the presence of only one conformer 3Ea in solution.

Solid-state ¹H NMR is applied to investigate the kinetics of diffusion of H₂O molecules in the fibrous zeolite natrolite [Na₂Al₂Si₃O₁₀]×2H₂O. It is found that the stepwise heating of the zeolite in air leads to the following pattern of molecular diffusion jumps: at first they increase in number and then decrease exponentially with time. Conducting such an experiment in an aqueous medium leads to the opposite effect. The results obtained confirm our previous suggestion about the importance of interstitial defects, or over-hydrated local states, in molecular diffusion.

The ²⁷Al, ¹H MAS NMR method is used to study initial nanosized metastable aluminum oxides of a pseudoboehmite series (g- and d-Al₂O₃) after being coated with graphene (С@Al₂O₃) and annealed in the air (С@Al₂O₃-Т). It is demonstrated that aluminum nanoparticles coated with graphene and annealed at high temperatures (to 750°C for g and 1180°C for d) preserve their phase composition but differ from initial oxides by a very low concentration of defects (ОН groups). After the annealing of the graphene coating the hydroxyl cover of oxides is reduced, however, the set of ОН groups differs greatly from that of the initial oxides. Only one type of terminal ОН groups with a ~0.2 ppm shift and one type of bridging m²-ОН groups with a 1.8 ppm shift for g-Al₂O₃ from OH-m²-Al_VAl _n and 2.1 ppm for d-Al₂O₃ OH-m²-Al_IVAl _n are observed. The data obtained make it possible to characterize in detail the d-Al₂O₃ pure phase.

It is considered practically impossible to differentiate between oxygen and fluorine atoms by X-ray diffraction in disordered structures of oxyfluoride compounds due to the similarity of their ionic radii and diffusion factors. Indeed, many transition metal oxyfluoride compounds containing polar pseudo-octahedral MO _x F_{6- x} ( x = 1-3) anions form crystal structures without any fluorine-oxygen (F/O) ordering owing to a large number of local anion configurations. Because of this static disorder, it is impossible to determine the positions of O and F atoms and find the real geometry of the polyhedron. However, this becomes possible in the case of dynamic disorder of oxyfluoride anions when the central atom is displaced from the center of the octahedron toward a vertex, edge, or face (depending on the number of oxygen atoms in the polyhedron), which enables the identification of O and F atoms owing to inherent differences between M-O and M-F bonding. On cooling, such compounds undergo phase transitions of the order-disorder type with substantial changes in the entropy. The examples of static and dynamic orientational disorder in oxyfluoride compounds of d ⁰ transition metals are given.

The reasons for the preference of glide planes in natural crystals are considered by studying the results of an X-ray crystallography analysis of the minerals salzburgite, eldragonite, izoklakeite, and vikingite. The glide planes organize the combination of right- of atomic fragments, which appear during crystallization, and contribute to a uniform distribution of atoms in complex compositions and a more dense and symmetrical packing. The fact that the structures have cation and anion sublattices with similar dimensions and orientations creates a situation similar to that of beats in oscillatory systems and, hence, modulates the intensity of X-ray reflections. The progressively increasing number of structures where individual atomic positions are occupied by two or more types of atoms suggests a stable geometry of the corresponding atomic sublattices with respect to compositional variations. Analysis of these “skeletal” sublattices is a key to understanding the solid-phase transformations, contact interactions, and dynamic processes in mineral associations.

The Rietveld method is used to determine the structure of two samples of high-hydrated zeolite paranatrolite: {Na_1.15Ca_0.38Sr_0.04(H₂O)_3.1}[Al_2.19Si_2.81O₁₀] (Vishnevye Mountains, Urals) and {Na_2.01K_0.04H_0.04(H₂O)_3.8}[Al_2.10Si_2.90O₁₀] (Kirov Mine, Khibiny Massif). Paranatrolite from the Vishnevye Mountains is characterized by the presence of split water positions and a relatively low total H₂O content. Local water-cation assemblages (WCAs) of three configurations are identified in the statistical “mixture”. The extraframework subsystem in the structure of Khibiny paranatrolite is made of WCAs of one configuration. The H₂O content of this mineral is close to the maximum possible amount and is a record-breaker for natrolite-type minerals.

The inclusion compound of the composition [Zn₂(dmf)(bdc)(lac)]×[Mn(C₅H₅)(CO)₃] (C₅H₅ = cyclopentadienyl) is obtained by keeping a mixture of crystals of a porous homochiral metal-organic polymer of the composition [Zn₂(dmf)(bdc)(lac)]×DMF (DMF = N,N¢-dimethylformamide, H₂bdc = terephthalic acid, H₂lac = S -lactic acid) with the excess of cymantrene at 100°C, and the crystal structure of this compound is determined.

Based on the hypothesis advanced by S. P. Gabuda that the SiO₂ molecule could undergo a transition from the linear form to the isomeric form with a ring-shaped (bent) structure, an idea is proposed that when the mantle substance melts, a phase transition of the bent SiO₂ form into the linear SiO₂ form can occur in the lower mantle. This phase transition might be of great importance for the lower-mantle convection processes and also for the rise of mantle plumes carrying both heat energy, and broad range of platinum group and rare elements to the Earth surface.

The bibliometric and subject analysis of the scientific heritage of Professor S. P. Gabuda is carried out using the national (RSCI) and international (CAPlus, WoS, and Scopus) databases.