Anomalies of the external and internal gravitational fields of the Earth’s isostatically balanced crust in the quadratic approximation

Formulas that include the contribution from dipole-distributed anomalous masses represented as layers distributed in height relative to the reference ellipsoid to the gravitational field in the quadratic approximation have been derived. The relationships between the expansion coefficients of some function and its square in terms of spherical functions have been established. The contribution from the relief masses and the density jump at the Mohorovicic discontinuity is used to illustrate the results.     

μ-Oxo-Bis(Tetraphenylantimony): Synthesis,Structure, and Reactions

Heating of a solution of pentaphenylantimony in toluene in atmospheric oxygen affords -oxo-bis(tetraphenylantimony) (I) in a 63% yield. The latter compound can be converted to bis(tetraphenylantimony) carbonate or phthalate by the action of carbon dioxide or phthalic anhydride, respectively. According to X-ray diffraction data, the antimony atoms in compound Ihave a distorted trigonal-bipyramidal coordination (Sb–O 2.0050(4) Å, the SbOSb angle 151.71(9)°). The molecule of bis(tetraphenylantimony) phthalate is composed of two equal fragments, and its Sb atoms also have trigonal-bipyramidal coordination (Sb–O 2.2421(8) Å; Sb–C 2.176(1), 2.115(1), 2.130(1), and 2.137(1) Å).     

On one possibility of determining the atom position in the crystal unit cell

The possibility of the determination of the position of an atom incorporated in the crystal unit cell by measuring the yield of characteristic radiation of this atom, excited by an X-ray wave nonuniform over the cell cross section, is shown. Such a wave can appear, in particular, in the mode of dynamical diffraction of an ordinary plane wave.     

Natural radioactivity in springs of Sverdlovsk region,Middle Urals,Russia

Journal of Radioanalytical and Nuclear Chemistry - Activity concentrations of natural radionuclides were determined in water from 31 springs of Sverdlovsk region, Middle Urals, Russia. Activity...     

Analyzing the adsorption of blood plasma components by means of fullerene-containing silica gels and NMR spectroscopy in solids

The results from studying the adsorption of blood plasma components (e.g., protein, triglycerides, cholesterol, and lipoproteins of low and high density) using silica gels modified with fullerene molecules (in the form of C₆₀ or the hydroxylated form of C₆₀(OH) _x ) and subjected to hydration (or, alternatively, dehydration) are presented. The conditions for preparing adsorbents that allow us to control the adsorption capacity of silica gel and the selectivity of adsorption toward the components of blood plasma, are revealed. The nature and strength of the interactions of the introduced components (fullerene molecules and water) with functional groups on the silica surface are studied by means of solid state NMR spectroscopy (NMR-SS). Conclusions regarding the nature of the centers that control adsorption are drawn on the basis of NMR-SS spectra in combination with direct measurements of adsorption. The interaction of the oxygen of the hydroxyl group of silica gel with fullerene, leading to the formation of electron-donor complexes of C₆₀-H, C₆₀-OH, or C₆₀-OSi type, is demonstrated by the observed changes in the NMR-SS spectra of silica gels in the presence of fullerene.     

Collimator-size effect on the parametric-radiation spectrum

It is shown that, by varying the angular size of a collimator, the spectral distribution of parametric x-ray radiation can be split into two isolated peaks and that the center of the spectral distribution of this radiation is shifted in frequency in response to an increase in the collimator size. It is also predicted that an increase in the angular size of the collimator will lead to a substantial modification of the character of the orientation dependence of the radiation spectrum.     

Synthesis and molecular structure of the complex [Ph3Sb(NO3)]2O·Me2CO

The reaction of silver nitrate with Ph₃-SbBr₂ in an ethanol-acetone solution afforded the complex [Ph₃Sb(NO₃)]₂O·Me₂C=O (1). According to the data of X-ray diffraction study of crystals of1, molecule1 contains a nonlinear O-bridge, which links two Sb atoms. The Sb atoms have a trigonal-bipyramidal configuration. The NO₃ group and the bridging oxygen atom are in axial positions and the three Ph substituents are in equatorial positions. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 174–176, January, 1999.     

X-ray spectra and electronic structure of K x C60

Highly resolved CK_α spectra of the compounds K₃C₆₀ and K₆C₆₀ synthesized by thermal decomposition of potassium azide in a vacuum chamber of an X-ray tube were obtained. The possibility of monitoring the extent of intercalation of fullerenes by the CK_α spectra is demonstrated. The results are compared with the MNDO calculations for K₆C₆₀. The data are used to construct a diagram of the structure of the highest occupied and C1s levels in the series C₆₀−K₃C₆₀−K₆C₆₀. Deceased. Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 3, pp. 514–519, May–June, 1996.     

μ-Oxo-Bis[(Bromo)Tri-m-Tolylantimony]: Synthesis and Structure

-Oxo-bis[(bromo)tri-m-tolylantimony] was synthesized by the reaction of tri-m-tolylstibine with hydrobromic acid in ether in the presence of hydrogen peroxide. The complex was structurally characterized by X-ray diffraction analysis. The coordination polyhedron of the Sb atoms is a distorted trigonal bipyramid with the bromine and the bridging O atoms in the axial positions. The Sb(1)–C(Ph) distances vary from 2.085(9) to 2.111(8) Å. The Sb(1)–Br(1) and Sb(2)–Br(2) bond lengths are 2.739(2) and 2.735(2) Å, respectively; the Sb–O_br distances measure 1.949(1) Å.