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1.
Kavun V. Ya. Uvarov N. F. Sergienko V. I. Zemnukhova L. A. 《Russian Journal of Coordination Chemistry》2004,30(7):505-510
The internal mobility of fluoride ions and electrophysical characteristics of alkali metal tetrafluoroantimonates(III) (M = Na, K, Rb, and Cs) are studied by 19F NMR and impedance spectroscopies. The types of ion motions in the anionic sublattice of these compounds are determined in the 180-510 K temperature range. The superionic conductivity of the MSbF4 compounds is established above 480 K ( 2.9 × 10-2 to 1.3 × 10-4 S/cm). 相似文献
2.
V. Ya. Kavun N. F. Uvarov A. B. Slobodyuk V. K. Goncharuk A. Yu. Kotenkov I. A. Tkachenko A. V. Gerasimenko V. I. Sergienko 《Russian Journal of Electrochemistry》2005,41(5):501-509
Methods of (19F, 1H) NMR and impedance spectroscopy are used to investigate the internal mobility and ionic conduction in solid solutions arising in the system PbF2-ZrF4 and polycrystals KSnZrF7, Li(Na)(NH4)6Zr4F23, and M2ZrF6 (M = K, NH4). Factors responsible for the form of ionic motions and their energetics at 170–550 K are considered. It is established that the phase transitions in these compounds are connected with the crystal transition to a superionic state and that the high ionic (superionic) conductivity of beta phases is due to the diffusion of fluoride ions, ammonium cations, and possibly alkali metal cations. The obtained data testify to a substantial role of chainlike aggregation of anionic groupings and a variableness of structural mechanisms of formation of such chains in fluorozirconates for the development of translational diffusion in these compounds.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 573–582.Original Russian Text Copyright © 2005 by Kavun, Uvarov, Slobodyuk, Goncharuk, Kotenkov, Tkachenko, Gerasimenko, Sergienko. 相似文献
3.
Dynamics of octahedral ions in crystal compounds MM′AF6 (M, M′=Li, Na, K, Rb, Cs; A=Ge, Ti) has been studied in the temperature range 115–500 K. Types of inner motions of complex
ions have been established, and their activation energies have been estimated. First-order transition has been found in compound
LiRbTiF6.
Institute of Chemistry, Far-East Branch, Russian Academy of Sciences. Translated fromZhurmal Strukturnoi Khimii, Vol. 36, No. 4, pp. 697–702, July–August, 1995.
Translated by L. Smolina 相似文献
4.
V. Ya. Kavun N. A. Didenko A. B. Slobodyuk I. A. Tkachenko A. V. Gerasimenko N. F. Uvarov V. I. Sergienko 《Journal of Structural Chemistry》2005,46(5):839-847
The mobility of fluoride and ammonium ions (180–480 K) in compounds K2? n (NH4)nZrF6 (0.2 ≤ n ≤ 1.70) was investigated by 19F and 1H NMR. Correlations have been found between the composition of the cation sublattice, the character of ion motions, and phase transition temperature in these compounds. The hightemperature modifications with n ≥ 0.85 of the compounds are characterized by translational diffusion of fluoride and ammonium ions and by uniaxial anisotropy of the 19F magnetic shielding tensor. The electrophysical characteristics of these compounds were studied in the temperature range 300–480 K. 相似文献
5.
N. V. Petrochenkova I. A. Tkachenko A. G. Mirochnik V. E. Karasev V. Ya. Kavun 《Optics and Spectroscopy》2010,109(6):917-920
This paper reports on the results of an investigation of the luminescence and magnetic properties of europium(III) carboxylates, which are determined by the structure of the Stark and Zeeman sublevels. It has been established that the energy splittings λlum between the 7 F 0 ground level and the 7 F 1 term in the luminescence spectra of these compounds well correlate with the energy splittings λmagn obtained from magnetochemical measurements. 相似文献
6.
V. Ya. Kavun N. F. Uvarov L. A. Zemnukhova A. S. Ulikhin N. A. Didenko O. V. Brovkina V. I. Sergienko 《Russian Journal of Electrochemistry》2013,49(7):633-644
The ion mobility, phase transitions, and ionic conductivity in the crystal phases in the KF-NH4F-SbF3 system were studied by NMR, DTA, and impedance spectroscopy. An analysis of the 19F and 1H NMR spectra showed how the character of ionic motions in the fluoride and proton sublattices changed with temperature. The types and temperature ranges of ionic motions were determined. Diffusion of the fluoride and partially ammonium ions was found to be the dominant form of ionic motion in the high-temperature modifications formed as a result of phase transitions. According to the electrophysical data, the high-temperature K1 ? x (NH4) x SbF4 phases (0.05 ≤ x ≤ 0.75) are superionic, their conductivity reaching ~10?2–10?3 S/cm at 450–500 K. 相似文献
7.
L. A. Zemnukhova A. A. Udovenko A. E. Panasenko V. Ya. Kavun G. A. Fedorishcheva 《Russian Journal of Inorganic Chemistry》2013,58(12):1452-1456
Na2Sb5F9O3(NCS)2, a new complex, has been synthesized from NaSCN and SbF3 aqueous solutions and studied by chemical, X-ray diffraction, and thermal analyses and IR, 121,123Sb NQR, and 19F NMR spectroscopy. Its layered structure (triclinic symmetry system, a = 6.9998(1) Å, b = 9.4180(1) Å, c = 13.1094(2) Å, α = 74.815(1)°, β = 78.188(1)°, γ = 82.779(1)°, Z = 2, space group P $\bar 1$ ) is built of Na+ cations and [Sb10F18O6(NCS)4]4? decanuclear complex anions that consist of two [Sb5F9O3(NCS)2]2? pentanuclear complex anions linked by two weak Sb-F ionic bonds (2.529(2) Å). Decanuclear complex anions are linked into layers by secondary Sb…F bonds and Na-F bonds. Van der Waals interactions link these layers into a framework. The complex is stable up to 200°C. 相似文献
8.
Gerasimenko A. V. Merkulov E. B. Tkachenko I. A. Kavun V. Ya. Goncharuk V. K. Sergienko V. I. 《Russian Journal of Coordination Chemistry》2002,28(12):839-842
The crystal structure of SnZrF6 is determined. The compound is synthesized by slow crystallization from a melted mixture of SnF2 and ZrF4 (2 : 1). The crystals are monoclinic: a = 6.6119(5), b = 5.2503(5), c = 6.9929(6) Å, = 114.239(4)°, space group P2/n, Z = 2. The structure is layered. The layers are formed from the chains of edge-sharing, eight-vertex zirconium polyhedra and Sn2+ cations. The Zr–F and Sn–F bond lengths in the layer vary from 2.309(1) to 2.269(1) Å and from 2.186(1) to 2.361(1) Å, respectively. The layers are linked by intermolecular Sn–F bonds with lengths of 2.868(1) and 2.871(1) Å. 相似文献
9.
The flow with a free-stream Mach number M
∞ = 6 around a cylindrical body with a sharp spike is studied. The existence of a supersonic reverse flow for one of the phases
of the pulsating flow regime is experimentally validated. A range of spike lengths is determined, which ensures a region of
a supersonic reverse flow near the side surface of the spike. The time of existence of the supersonic reverse flow region
is shown to be 0.15 of the period of pulsations if the spike length equals the model diameter.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 4, pp. 30–39, July–August, 2007. 相似文献
10.
O. Yu. Kavun A. I. Popykin R. A. Shevchenko S. A. Shevchenko 《Physics of Atomic Nuclei》2012,75(13):1596-1602
This paper presents comparisons between the effectiveness of the emergency protection under both stationary and nonstationary formulations calculated with the use of the RADUGA-7.5 package [1] and experimental data obtained in measuring the ??weight?? of the emergency protection in the process of physical start-up of the VVER-1000 reactor of unit no. 3 of the Kalinin NPP. On the basis of the results obtained, recommendations are given on comparing the measured and calculated reactivity and parameters determined by using its value. 相似文献