Abstract:Quartz samples of different origin from 10 localities in the Southern Ural region, Russia have been investigated to characterize their trace element compositions and defect structures. The analytical combination of cathodoluminescence (CL) microscopy and spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and trace-element analysis by inductively coupled plasma mass spectrometry (ICP-MS) revealed that almost all investigated quartz samples showed very low concentrations of trace elements (cumulative concentrations of <50 ppm with <30 ppm Al and <10 ppm Ti) and low abundances of paramagnetic defects, defining them economically as "high-purity" quartz (HPQ) suitable for high-tech applications. EPR and CL data confirmed the low abundances of substitutional Ti and Fe, and showed Al to be the only significant trace element structurally bound in the investigated quartz samples. CL microscopy revealed a heterogeneous distribution of luminescence centres (i.e., luminescence active trace elements such as Al) as well as features of deformation and recrystallization. It is suggested that healing of defects due to deformation-related recrystallization and reorganization processes of the quartz lattice during retrograde metamorphism resulted in low concentrations of CL activator and other trace elements or vacancies, and thus are the main driving processes for the formation of HPQ deposits in the investigated area.

Статья посвящена 150-летнему юбилею Периодической таблицы химических элементов Д.И.Менделеева. Фундаментальный закон природы, открытый Д.И.Менделеевым, имеет аномалии и парадоксы, связанные с некоторыми группами металлов. При изучении физико-химических свойств комплексных металлических соединений можно встретить большое количество несоответствий, а именно, места расположения элементов в группах, которые в первую очередь относятся к металлам с разной валентностью. Изучая подходы и методы прогнозирования расстановки химических элементов, можно установить, что многие различия по некоторым металлам были устранены Д.И.Менделеевым в процессе формирования Периодической системы химических элементов. Д.И.Менделеев выработал принцип, исключающий подобные ошибки при нахождении и открытии новых элементов. Аналитические исследования, проведенные российским ученым, помогли вычислить атомные массы и описать свойства трех элементов, не известных еще в тот период времени -«экабора», «экасилиция», «экаалюминия», существование которых доказано и подтверждено последующими открытиями скандия, германия, бора, галлия. В работе дана значимая оценка прогнозирования металлов в различных группах периодической системы. Изменение свойств некоторых металлов существенно повлияло на их расположение в таблице Д.И.Менделеева.

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Three new rubidium polychromates, Rb2[(UO2)(Cr2O7)(NO3)2] (1), γ-Rb2Cr3O10 (2) and δ-Rb2Cr3O10 (3) were prepared by combination of hydrothermal treatment at 220 °C and evaporation of aqueous solutions under ambient conditions. Compound 1 is monoclinic, P 2 1 / c $P{2}_{1}/c$ , a = 13.6542(19), b = 19.698(3), c = 11.6984(17) Å, β = 114.326(2)°, V = 2867.0(7) Å3, R 1 = 0.040; 2 is hexagonal, P 6 3 / m $P{6}_{3}/m$ , a = 11.991(2), c = 12.828(3) Å, γ = 120°, V = 1597.3(5) Å3, R 1 = 0.031; 3 is monoclinic, P 2 1 / n $P{2}_{1}/n$ , a = 7.446(3), b = 18.194(6), c = 7.848(3) Å, β = 99.953(9)°, V = 1047.3(7) Å3, R 1 = 0.037. In the crystal structure of 1, UO8 bipyramids and NO3 groups share edges to form [(UO2)(NO3)2] species which share common corners with dichromate Cr2O7 groups producing novel type of uranyl dichromate chains [(UO2)(Cr2O7)(NO3)2]2−. In the structures of new Rb2Cr3O10 polymorphs, CrO4 tetrahedra share vertices to form Cr3O10 2− species. The trichromate groups are aligned along the 63 screw axis forming channels running in the ab plane in the structure of 2. The Rb cations reside between the channels and in their centers completing the structure. The trichromate anions are linked by the Rb+ cations into a 3D framework in the structure of 3. Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems is discussed.

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The scientific basis for the development of innovative materials (microporous, nanostructured, composite) based on natural (technogenic and synthetic) aluminosilicate raw materials determine prototypes of new technologies in modern industry. Inspired by this, we studied interphase boundary interactions of the “aluminosicate resource – nanoproduct” type system as a key factor of aggregation and nanostructuring in the processes of mineral formation and synthesis. To study features of the heterogeneity of the structure and their correlations with the thermodynamic parameters of the formation of mineral aggregates and individuals, instrumental and methodological resources were used. Based on previous and current studies of natural, synthesized and technogenic aluminosilicates (zeolites, clays, halloysite, fly ash, halloysite nanotubes, etc., features of the constitution and surfaces, sorption, ion-exchange, catalytic, –QS and +QS, biocompatibility, nontoxicity and other useful properties) the prospects for promotion of their industrial application were considered.

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It was found as a result of SIMS study of beryl with various color zoning from the Uralian Izumrudnye Kopi that the content of a number of trace elements regularly varies to the margin of the crystal regardless of the color nature of the central and marginal crystal parts. The Na, Mn, Ga, Fe and Rb content increases towards the periphery of both crystals forming a U-shaped zoning. This pattern is less pronounced for Ni and Co. The Ti content, on the contrary, decreases towards the crystal margin forming a bell-shaped zoning. The distribution of a number of elements demonstrates another zoning pattern. For the beryl crystal (sample 24), the color saturation and transparency of which increases from a colorless to green-yellow from the center to the periphery of the crystal, the Sc, Cr and V forms U-shaped zoning with an increasing content to the margin of the crystal and Li exhibits a bell-shaped zoning. In transparent beryl crystal with more intense green color in the center (sample 25), the zoning pattern is dramatically distinct: bell-shaped for Sc, Cr and V and U-shaped for Li. The content of each element for both crystals coincides in the marginal zones, which have color comparable in intensity and transparency, despite the diferent color pattern with a sharply contrast¬ing distribution in the central part. In discriminant diagrams proposed for the identifcation of emeralds from various world regions, the composition of beryl from the Uralian Izumrudnye Kopi correspond to the feld of compositions of the Uralian emeralds or is close to them.