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1.
G. A. Bandurkin N. N. Chudinova G. V. Lysanova K. K. Palkina E. V. Murashova V. A. Krut’ko G. M. Balagina 《Russian Journal of Inorganic Chemistry》2006,51(2):292-305
Specific features of the textures (the preferred orientation of the nanometer building blocks) in the structures of mixed-anion
compounds—rare-earth borogermanates, germanophosphates, and borotungstates that arise from the acid-base interaction in the
Ln2O3-B2O3-GeO2, Ln2O3-GeO2-P2O5, and Ln2O3-B2O3-WO3 systems (Ln = La-Gd)—have been studied. Based on characteristic texture traits, the mixed-anion compounds of early rare-earth
elements can be divided into three groups: (i) Ln2O3: ExOy > 1, (ii) Ln2O3: ExOy = 1, and (iii) Ln2O3: ExOy < 1. Because of the dominant structural effect of the basic oxide Ln2O3 in the compounds of the first group, the structures of Nd14O8(BO3)6(GeO4)2 and Pr11O10(GeO4)(PO4)3 are composed of infinite [LnOn] bands and layers and discrete groups [EOm] located in the interband and interlayer spaces. The dominant structural effect of the acid oxides [ExOy] in the compounds of the third group leads to the appearance of ring textures composed of [LnOn], as well as to the appearance of chains and networks composed of [EOm], in the structures of Ln(BGeO5) and Ln(BO2)(WO4).
Original Russian Text ¢ G.A. Bandurkin, N.N. Chudinova, G.V. Lysanova, K.K. Palkina, E.V. Murashcva, V.A. Krut’ko, G.M. Balagina,
2006, published in Zhurnal Neorganicheskoi Khimii, 2006, Vol. 51, No. 2, pp. 334–347. 相似文献
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The isotropic cationic networks (CNs) completing the anisotropic CNs ai isotropic CNs binary opposition are identical in the
structures of various rare earth compounds. 相似文献
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Bandurkin I. V. Peskov N. Yu. Savilov A. V. 《Radiophysics and Quantum Electronics》2003,46(12):957-966
We study a new regime of electron–wave interaction in microwave amplifiers and demonstrate its efficiency for a wide class of devices. A mildly relativistic millimeter-wave free-electron maser is calculated as a particular system implementing this regime. 相似文献
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G. A. Bandurkin V. A. Krut’ko G. V. Lysanova M. G. Komova 《Russian Journal of Inorganic Chemistry》2011,56(1):82-92
The cationic networks in the structures of the initial oxides and all binary and ternary compounds forming in the Ln2O3-GeO2-P2O5 systems have been studied. In the phase diagrams of the Nd2O3-GeO2-P2O5 and Er2O3-GeO2-P2O5 systems, the regions of the structural influence of individual compounds with topologically identical cationic networks—anisotropic
(A), combined (C), and isotropic (I)—are united into common areas. The A: C: I area ratio is 1: 1: 1 in the neodymium system
and 1.7: 1: 3.4 in the erbium system. 相似文献
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G. A. Bandurkin N. N. Chudinova G. V. Lysanova V. A. Krut’ko M. G. Komova G. M. Balagina 《Russian Journal of Inorganic Chemistry》2007,52(7):1081-1087
The structural aspects of the acid-base interaction in the course of formation of molybdates in the binary systems Ln2O3-MoO3 have been considered. The structures of rare earth molybdates inherit infinite bands of {[LnO n ]-[LnO n ]} dimers from the structures of Ln2O3 oxides. The nanostructural oxide “memory” of molybdates implies that the dimers in these bands retain approximately nanometer sizes and predominant mutual orientation despite the fact that, as the Mo formula content increases, the types of polyhedra in the dimers change and the contacts between dimers and, eventually, between the polyhedra in these dimers are lost. 相似文献
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V. A. Krut’ko V. P. Tarasov G. A. Bandurkin M. G. Komova 《Russian Journal of Inorganic Chemistry》2013,58(9):1090-1096
The structure of fine crystalline borogermanate La12GdEuB6Ge2O34 has been studied by NMR and IR spectroscopy. It has been demonstrated that this compound is isostructural to the homonuclear Ln14B6Ge2O34 compounds (Ln = Pr-Gd) and crystallizes in space group P31. The rare-earth elements have been distributed over the LnO n polyhedra in La12GdEuB6Ge2O34 by analogy with the known structures. Lanthanum can occupy positions with CN 7–10, and the symmetry of these LnO n coordination polyhedra is not higher than C 2v . In the La12GdEuB6Ge2O34 structure, the LnO n coordination polyhedra are formed by oxygen atoms of oxo groups and anions, some of the oxygen atoms being shared by LnO n polyhedra. The BO3 and GeO4 groups in the structure are also bridging, i.e., are involved in bonding of LnO n polyhedra. One of the B-O bonds in La12EuGd(BO3)6(GeO4)2O8 is elongated as compared with the B-O bond lengths in homonuclear compounds Pr14(BO3)6(GeO4)2O8 and Nd14(BO3)6(GeO4)2O8. In the La12GdEuB6Ge2O34 structure, germanium is located in isolated GeO4 tetrahedra with distorted T d symmetry. The local symmetry of lanthanum in fine crystalline La12GdEuB6Ge2O34 have been assessed using 139La NMR (B 0 = 7.04 T, room temperature). For comparison, binary lanthanum compounds with a simpler structure— LaBO3, La(BO2)3, and La2GeO5—have been used. The spectra of all compounds are rather broad (ν1/2 = 180–240 kHz). The 139La NMR spectra of the LaBO3, La(BO2)3, and La12GdEu(BO3)6(GeO4)2O8 borates show a signal at (1080 ± 40) ppm, which is absent in the spectrum of La2GeO5. The shape of the 139La NMR spectra of La12GdEu(BO3)6(GeO4)2O8 and LaBO3 is characterized by the second-order quadrupole splitting with a downfield shoulder. The similarity of these spectra points to close 139La NMR chemical shifts of La12GdEu(BO3)6(GeO4)2O8 and LaBO3. No quadrupole splitting was observed in the spectra of La(BO2)3 and La2GeO5. 相似文献
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G. A. Bandurkin N. N. Chudinova G. V. Lysanova V. A. Krut’ko M. G. Komova 《Russian Journal of Inorganic Chemistry》2006,51(3):429-437
Studying the textures (the preferred orientation of the nanometer building blocks) in the structures of neodymium tungstates shows that infinite dimeric bands {[LnOn]-[LnOn]}-{[LnOn]-[LnOn]} in a fluoritelike structure field of the Nd2O3-WO3 binary system undergo fragmentation and modification. The structural background (staggered arrangement of polyhedra) is determined by the like effects of both the basic oxide Ln2O3 (a fluorite-type structure) and the acid oxide WO3 (a ReO3-type structure). 相似文献