SovietRxiv · Open Access in English
Rediscovering the Soviet scientific archive, in English
25357 full-text translations 14926 English PDFs 22539 abstracts
Showing 50 of 4600 papers in Chemistry
This study examines whether amide resonance is inhibited when the amide nitrogen is incorporated into a three-membered ethylenimine ring. p-Bromobenzoylethylenimine and the comparison compound p-bromobenzoyldimethylamine were synthesized and analyzed by X-ray diffraction using Weissenberg photograph…
This study uses proton magnetic resonance to investigate proton positions and water molecule dynamics in natural edingtonite, a fibrous zeolite whose hydrogen atom arrangement had not been directly established. Single-crystal spectra were measured over a broad temperature range to separate room-temp…
The paper addresses competing structural models for antimony(III) tartrate complexes related to tartar emetic, particularly whether the complex is mononuclear or binuclear and whether water is coordinated to antimony. Single-crystal X-ray analysis was applied to the isostructural ammonium, rubidium,…
The crystal structure of di-p-tolyl disulfide is refined to clarify the role of sulfur lone electron pairs in aromatic disulfides. Starting from an earlier molecular model, the authors used three-dimensional Fourier electron-density synthesis and least-squares refinement of scale factors, atomic coo…
This paper investigates how the probability of deactivation of the first vibrational level of iodine molecules depends on the ratio of collision time to vibrational period, particularly in the poorly studied region where this ratio is near or below unity. Vibrational relaxation times were measured b…
The paper determines the crystal structure of a synthetic sodium zinc diorthosilicate phase, Na2Zn2Si2O7, obtained by hydrothermal synthesis in the Na2O, ZnO, SiO2 system and characterized by luminescent properties. Using Weissenberg X-ray intensity data, Patterson analysis, electron-density synthes…
The paper determines the crystal structure of vinogradovite, a monoclinic sodium titanium silicate mineral from alkaline pegmatites, using three-dimensional X-ray diffraction data and Patterson, minimization, and superposition methods in space group A2/a. The analysis revises the ideal formula to Na…
This paper examines crystal growth during solid solid polymorphic transformations in glutaric acid and hexachloroethane, extending earlier work on organic crystals. Using polarizing microscopy, controlled heating and cooling, and X-ray methods, the authors observe the formation and growth of faceted…
The paper addresses the unresolved relation between the dielectric constant of a liquid and the molecular dipole moment, noting limitations of the Debye and Onsager treatments and the need for a unified approach for pure liquids and solutions. It argues that the orienting field must be weaker than t…
This paper investigates multiphoton excitation and laser induced decomposition of organic molecules using high intensity ruby laser radiation and, for selected compounds, dysprosium laser irradiation. Luminescence measurements on polycrystalline samples at 77 K and 300 K show fluorescence consistent…
Infrared absorption spectra of tetraethoxysilane and methylethoxysilanes, with compositions varying from trimethylethoxysilane to tetraethoxysilane, are analyzed through integral intensities, peak absorption coefficients, and band half-widths in the 400 to 3000 cm⁻¹ region. The study assigns princip…
This paper investigates the structural origin of optical inhomogeneities in natural and synthetic quartz, including schlieren, banding, sectoriality, and zonal structures. Using X-ray diffraction topography with a Lang camera and comparing the resulting images with optical observations and etching p…
This paper investigates the hyperfine structure of electron paramagnetic resonance spectra of vanadium-containing borate, silicate, and phosphate glasses in order to relate spectral parameters to chemical bonding. Using room-temperature and liquid-nitrogen-temperature EPR measurements and an axial s…
The paper reports an X-ray crystallographic determination of the triclinic structure of potassium bichromate, K2Cr2O7, lopezite, using single-crystal diffraction data and three-dimensional Patterson and electron-density syntheses. The structure is refined in the centrosymmetric space group P1bar, wi…
The paper addresses the physicochemical effects attributed to magnetic treatment of water, especially the formation of crystallization centers and changes in surface tension in aqueous electrolyte solutions. It proposes a molecular model in which magnetic treatment promotes spatial separation of ion…
The paper determines the crystal structure of hydrothermally synthesized sodium samarium orthosilicate, NaSmSiO4, using single-crystal X-ray diffraction data. Patterson, ordinary Fourier, and difference Fourier syntheses establish a tetragonal body-centered cell with space group I4/m, parameters a =…
This paper investigates structural changes in alpha quartz during heating through the alpha to beta transition, with attention to whether atomic rearrangement occurs abruptly or over an extended temperature interval. Using x-ray diffuse scattering and Laue photography, the authors track changes in r…
The paper reports an X-ray crystallographic determination of the ternary compound Mo3CoSi, found in the Mo, Co, Si alloy system over a limited homogeneity range. Single-crystal and powder diffraction data were used to establish a tetragonal cell with a = 12.649 Å and c = 4.889 Å, to analyze extincti…
This paper investigates the crystal structures of cobalt(III) pentaammine complexes containing an inner-sphere thiocyanato group, with nitrate, chloride, or thiocyanate counterions. Using X-ray diffraction methods, including Fourier refinement for the nitrate salt and powder or limited single-crysta…
The paper determines the crystal structure of a synthetic sodium cadmium metasilicate phase in the Na2O, CdO, SiO2 system, with approximate composition Na2CdSi2O6. X-ray diffraction data, Patterson projections, and three-dimensional Fourier syntheses are used to establish a pseudotetragonal orthorho…
The study determines the crystal structure of liroconite, Cu2Al[AsO4][OH]4·4H2O, to clarify structural principles in copper arsenate and phosphate minerals related to the turquoise group. X-ray rotation and layer-line data using MoKα and CuKα radiation were analyzed through Patterson maps, electron-…
The paper reports an X-ray structural study of the double molybdate KY(MoO4)2, a compound distinguished among related molybdates and tungstates by pronounced cleavage. Using Weissenberg photographs with Mo K alpha radiation, Patterson projections, and least-squares refinement, the structure was dete…
This study investigates the long-range action of active centers on crystalline surfaces and its relation to surface structure. Using electron-microscopic chemical and electrical decoration through amorphous parlodion layers of varying thickness, the authors examined mica, silicon, quartz, sodalite, …
This paper constructs an equation of state for crystalline trinitrotoluene using the Debye, Einstein, Grüneisen approach, with separate treatments of intermolecular and intramolecular contributions to interaction energy and thermal motion. The model parameters are determined from experimental data o…
This paper reports the hydrothermal formation and characterization of rare-earth tungstate chlorides LnWO4Cl, where Ln is Ce, Pr, or Nd, produced from intermediate rare-earth tungstates in ammonium chloride containing media. The authors describe synthesis conditions, crystal habit, chemical and ther…
This study examines the low-temperature polarization spectra of asymmetric aza-tetrabenzoporphins and their magnesium complexes in order to clarify how aza substitution affects the electronic transitions of the porphyrin chromophore. Using polarization of fluorescence as a function of excitation wav…
This paper examines the classification of electronically excited states in uranyl compounds from electronic vibrational absorption and emission spectra. Arguing against a five state scheme that assigns ultraviolet absorption bands to the uranyl ion, the authors interpret experimental spectral eviden…
This paper reports an X-ray diffraction study of crystalline iodine at room temperature under pressures up to 60 kbar, motivated by earlier evidence for pressure-induced changes in its physical properties and Bridgman’s low-pressure phase transition. Powder diffraction patterns were measured in a hi…
This study examines the hydrothermal synthesis and crystallographic characterization of rare-earth oxytungstates with composition Ln2W2O9, where Ln is Ce, Pr, or Nd, in chloride aqueous media at high temperature and pressure. Crystals were obtained from rare-earth tungstate charges in concentrated o…
This paper reports the preparation and characterization of filamentary single crystals of magnesium oxide, an oxide of interest because of its high melting temperature. The crystals were grown by heating polycrystalline magnesium oxide at 1600 to 1700 degrees in a cryptol furnace, where transport re…
The paper reports an X-ray crystallographic determination of nitrobis(ethylenediamine)nickel chloride, synthesized as violet orthorhombic crystals with space group Fdd2 and eight formula units per unit cell. Using measured Mo K-alpha diffraction intensities and the material-point method, the authors…
The paper determines the crystal structure of iron molybdate, Fe2(MoO4)3, the active component of iron molybdenum oxide catalysts, for a class of small-cation molybdates whose structures had not previously been described. Single-crystal X-ray diffraction data were analyzed using Patterson methods, F…
This paper reformulates the principal computational expressions of crystal structure analysis in terms of common parameters of crystallographic symmetry groups. It decomposes symmetry operations into rhombic and nonequivalent transformations, then derives unified trigonometric formulas for electron …
A material point method is proposed for minimizing functionals arising in crystal structural analysis, treating the unknown parameters as coordinates of a point constrained to move on the surface defined by the functional. The paper derives differential equations for this motion under a conditional …
The paper reports an X-ray crystallographic determination of the synthetic sodium zincosilicate phase Na2ZnSiO4, obtained hydrothermally in a strongly alkaline Na2O, ZnO, SiO2, H2O system and noted for Mn-activated green luminescence and a strong piezoelectric effect. Single-crystal diffraction data…
This paper investigates the fine structure of the scandium K-beta X-ray fluorescence emission spectrum in metallic scandium and in scandium diboride, carbide, nitride, and oxide, with the aim of relating spectral features to valence-band structure and chemical bonding. Using secondary excitation and…
This paper examines the mechanism by which thallium enters galena, focusing on the proposed coupled substitution of lead by monovalent thallium and trivalent bismuth or related elements. Synthetic compositions in the PbS, BiTlS2 system were prepared from pure elements and studied by thermal analysis…
This paper proposes a procedure for accounting for anharmonicity in molecular vibrations using general formulas for vibrational transition frequencies and successive approximations. The method expresses anharmonic force constants in natural or symmetry coordinates, derives the transformation to norm…
This paper examines whether the fluorescence quantum yield of solutions of polyatomic molecules decreases under long-wavelength, anti-Stokes excitation, or whether reported decreases arise from extrinsic effects. Using relative quantum-yield measurements with an integrating sphere and a comparison o…
The paper addresses the statistical theory of adsorption with explicit allowance for interactions among adsorbed particles, using molecular distribution functions rather than a separation into bulk and surface phases. Starting from the Bogolyubov hierarchy, the authors introduce an approximate closu…
This study investigates the quasilinear electronic spectra of magnesium and zinc derivatives of tetrabenzoporphin and phthalocyanine as model chlorophyll-like metalloporphyrins. Using Shpol’skii-type spectra in frozen n-octane matrices at 77 K with selected solvent additives, the authors obtained su…
Anhydrous copper propionate and copper n-butyrate were examined as initial representatives of copper fatty acid salts, motivated by EPR evidence for exchange-bonded copper pairs and by the limited structural knowledge of metallic soaps. Single crystals obtained from anhydrous acids were studied by X…
An X-ray structural study was carried out to test the proposed formula of a nickel hydrazinecarbonic compound previously assigned from analytical, conductivity, and chemical data. Using Cu K radiation, electron-density maps, interatomic function projections, and least-squares refinement, the monocli…
This paper examines the crystal structure and symmetry of Canadian niocalite, addressing conflicting earlier assignments of monoclinic and orthorhombic symmetry. Single-crystal X-ray photographs, Patterson projections, minimization functions, and projected electron-density refinement were used to de…
This paper examines the high-temperature reaction of graphitized carbon with carbon dioxide above about 2300 K, where gas penetration into the specimen is excluded but changes in the density of the solid are observed. Using spherical carbon specimens, the authors measured radial density profiles aft…
This paper examines the distinction between exact natural vibrational coordinates, defined by changes in molecular geometrical parameters, and approximate natural coordinates, defined as linear functions of atomic displacements from equilibrium. It shows that approximate coordinates simplify the kin…
The paper determines the crystal structure of hydrothermally synthesized cadmium tungstate, CdWO4, as an end member of the monoclinic wolframite-type tungstates with medium divalent cations. X-ray precession data and Patterson and difference Fourier analyses are used to locate Cd, W, and O atoms in …
This paper investigates whether polymorphic transformations in organic crystals proceed by the same layer-by-layer growth mechanism known for crystal growth from liquids and vapors. Using optical microscopy and microcinematography, the authors observed the alpha to beta transformation of n-dichlorob…
This paper reports the synthesis and characterization of previously undescribed stereoisomeric propenyl derivatives of germanium and related isopropenyl compounds. Tetra-cis-propenylgermane, tetra-trans-propenylgermane, tetraisopropenylgermane, cis- and trans-triethylpropenylgermane, and triethyliso…
