Registration Number
0219U003048,
0116U002521
, R & D reports
Title
Polyoxomolybdates and polyoxotungstates with single, double, and triple charged metal cations for the development of new materials
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Head
Rozantsev Georgii M., Доктор хімічних наук
Registration Date
16-01-2019
Organization
Donetsk State University
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The formation of cerium orthotungstate Ce2(WO4)3·9H2O from non-acidified solution of Na2WO4 (Z = ?(H+)/?(WO42-) = 0.00) was determined by the chemical analysis, XRD, and FTIR spectroscopy. From aqua-acetone media (v/v = 50/50) at Z = 0.80 the sodium heteropoly decatungstocerate (III) Na9[Ce(W5O18)2]·28H2O with Peacock-Weakley anion structure was synthesized. From acidified up to Z = 0.80 aqueous solution of sodium tungstate without acetone adding the acid sodium heteropoly decatungstocerate (IV) Na6H2[Ce(W5O18)2]·30H2O with Peacock-Weakley anion structure was synthesized. From the solution with Z = 1.00 the cerium heptatungstate Ce2W7O24·20H2O was synthesized, and by XRD it was shown that it thermal decomposition accompanied with crystallization of Ce4W9O33 and WO3 phases. By the chemical analysis and FTIR spectroscopy it was shown that the Ce5[HW7O24]3·56H2O was synthesized from solution with Z = 1.17, and by XRD method it was shown that calcination of Ce5[HW7O24]3·56H2O at 5000C occurs with only WO3 phase crystallization, and calcination at 7000C accompanied with crystallization of Ce4W9O33 phase. By the chemical analysis and FTIR spectroscopy it was shown that the cerium paratungstates B - Ce10[W12O40(OH)2]3·94H2O and Na10Ce20[W12O40(OH)2]7·180H2O were synthesized from equilibria solutions with Z = 1.17 and 1.29, respectively, and Na2Ce2[Ce2(H2O)10W22O72(OH)2]·35H2O with lacunar metatungstate-anions as ligands was synthesized from the solution at Z = 1.364. The conditions for the synthesis of novel praseodymium(III)-containing salt, Na9[Pr(W5O18)2]?34.25H2O, with heteropoly tungstate anion were determined. By the methods of chemical analysis, FT-IR, and FT-Raman spectroscopy it was shown that sodium heteropoly decatungstopraseodymate(III) Na9[Pr(W5O18)2]?34.25H2O was precipitated from Na2WO4 solution under Z=?(H+)/?(WO42-)=0.80 after adding of acetone. By FT-IR and FT-Raman spectroscopy, the heteropoly anion is shown to belong to the Peacock-Weakley structural type. By the method of scanning electron microscopy it was shown that the grain size of Na9[Pr(W5O18)2]?34.25H2O is within the range of 200-450 nm. Homogeneity of the obtained phase was confirmed by the uniform contrast of the surface mode of backscattered electrons. An X-ray single crystal analysis was carried out and crystal structure for Na9[Pr(W5O18)2]?34.25H2O was determined. It was established that no polytungstate structures of this type (both the unit cell parameters and the composition and packing within the structure) are described in the literature. Neodymium substitution with rare earth elements (REE) was studied in the systems Nd5 xLnxMo3O16 (Ln = La, Ce, Pr) by means of X-ray powder diffraction (including the Rietveld algorithm), scanning electron microscopy (SEM) and by measurements of the electrical conductivity. At x values of 0, 0.5, 0.3, and 5.0 the mixtures of REE oxides with MoO3 transform to single-phase solid solutions with fluorite structure and doubled unit cell parameters as a result of solid-state reactions occurring at 1050°C. In the systems with La and Pr the unit cell parameters of solid solutions increase as x increases while in the system with Ce these parameters decrease. Conductivity of ceramic solid electrolytes increases up to 17 times compared with the unmodified Nd5Mo3O16.
Product Description
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Єрошина Катерина Вікторівна
Іванцова Елла Сергіївна
Баумер Вячеслав Миколайович
Гетьман Євген Іванович
Гумерова Надія Ісмагілівна
Марійчак Олександра Юріївна
Радіо Сергій Вікторович
Розанцев Георгій Михайлович
Румянцева Жанна Олександрівна
Усачов Олег Михайлович
Шевченко Марія Миколаївна
Шульжук Богдан Володимирович
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2020-04-02
