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Title: Selective Se-for-S substitution in Cs-bearing uranyl compounds

Abstract

Phase formation in the mixed sulfate-selenate aqueous system of uranyl nitrate and cesium nitrate has been investigated. Two types of crystalline compounds have been obtained and characterized using a number of experimental (single crystal XRD, FTIR, SEM) and theoretical (information-based complexity calculations, topological analysis) techniques. No miscibility gaps have been observed for Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se), which crystallizes in tetragonal system, P-42{sub 1}m, a =9.616(1)–9.856(2), c =8.105(1)–8.159(1) Å, V =749.6(2)–792.5(3) Å{sup 3}. Nine phases with variable amount of S and Se have been structurally characterized. The structures of the Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se) compounds are based upon the [(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}]{sup 2-} layers of corner-sharing uranyl pentagonal bipyramids and TO{sub 4} tetrahedra. The layers contain two types of tetrahedral sites: T1 (3-connected, i.e. having three O atoms shared by adjacent uranyl polyhedra) and T2 (4-connected). The Se-for-S substitution in tetrahedral sites is highly selective with smaller S{sup 6+} cation showing a strong preference for the more tightly bonded T2 site. Crystallization in the pure Se system starts with the formation of Cs{sub 2}[(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)](H{sub 2}O) crystals, its subsequent dissolution and formation of Cs{sub 2}[(UO{sub 2}){submore » 2}(SeO{sub 4}){sub 3}]. The information-based structural complexity calculations for these two phases support the rule that more topologically complex structures form at the latest stages of crystallization. - Graphical abstract: Nine phases representing the Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se) solid solution series with variable amount of S and Se have been prepared by isothermal evaporation from aqueous solutions and characterized using a number of experimental and theoretical techniques. No immiscibility is observed between the pure sulfate and selenate compounds. The Se-for-S substitution in tetrahedral sites is highly selective with smaller S{sup 6+} cation showing a strong preference for the more tightly bonded 4-connected site. - Highlights: • Single crystals of novel mixed sulfate-selenate uranyl oxysalts were prepared by evaporation method. • Topological analysis and information-based complexity calculations were used for structure description. • The selective Se-for-S substitution was observed. • Evolution of phase formation in the aqueous Cs{sup +}–UO{sub 2}{sup 2+}–SO{sub 4}{sup 2–}–SeO{sub 4}{sup 2–} system was analyzed.« less

Authors:
 [1]; ;  [1];  [2]
  1. Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg, Russia Federation (Russian Federation)
  2. Far Eastern Federal University, Suhanova st. 8, Vladivostok 690950 (Russian Federation)
Publication Date:
OSTI Identifier:
22658245
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 248; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; AQUEOUS SOLUTIONS; CARBON SULFIDES; CATALYST SUPPORTS; CESIUM IONS; CRYSTALLIZATION; FOURIER TRANSFORMATION; INFRARED SPECTRA; MONOCRYSTALS; SCANNING ELECTRON MICROSCOPY; SELENATES; SOLID SOLUTIONS; SULFUR IONS; URANIUM DIOXIDE; X-RAY DIFFRACTION

Citation Formats

Gurzhiy, Vladislav V., E-mail: vladgeo17@mail.ru, Tyumentseva, Olga S., Krivovichev, Sergey V., and Tananaev, Ivan G. Selective Se-for-S substitution in Cs-bearing uranyl compounds. United States: N. p., 2017. Web. doi:10.1016/J.JSSC.2017.02.005.
Gurzhiy, Vladislav V., E-mail: vladgeo17@mail.ru, Tyumentseva, Olga S., Krivovichev, Sergey V., & Tananaev, Ivan G. Selective Se-for-S substitution in Cs-bearing uranyl compounds. United States. doi:10.1016/J.JSSC.2017.02.005.
Gurzhiy, Vladislav V., E-mail: vladgeo17@mail.ru, Tyumentseva, Olga S., Krivovichev, Sergey V., and Tananaev, Ivan G. Sat . "Selective Se-for-S substitution in Cs-bearing uranyl compounds". United States. doi:10.1016/J.JSSC.2017.02.005.
@article{osti_22658245,
title = {Selective Se-for-S substitution in Cs-bearing uranyl compounds},
author = {Gurzhiy, Vladislav V., E-mail: vladgeo17@mail.ru and Tyumentseva, Olga S. and Krivovichev, Sergey V. and Tananaev, Ivan G.},
abstractNote = {Phase formation in the mixed sulfate-selenate aqueous system of uranyl nitrate and cesium nitrate has been investigated. Two types of crystalline compounds have been obtained and characterized using a number of experimental (single crystal XRD, FTIR, SEM) and theoretical (information-based complexity calculations, topological analysis) techniques. No miscibility gaps have been observed for Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se), which crystallizes in tetragonal system, P-42{sub 1}m, a =9.616(1)–9.856(2), c =8.105(1)–8.159(1) Å, V =749.6(2)–792.5(3) Å{sup 3}. Nine phases with variable amount of S and Se have been structurally characterized. The structures of the Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se) compounds are based upon the [(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}]{sup 2-} layers of corner-sharing uranyl pentagonal bipyramids and TO{sub 4} tetrahedra. The layers contain two types of tetrahedral sites: T1 (3-connected, i.e. having three O atoms shared by adjacent uranyl polyhedra) and T2 (4-connected). The Se-for-S substitution in tetrahedral sites is highly selective with smaller S{sup 6+} cation showing a strong preference for the more tightly bonded T2 site. Crystallization in the pure Se system starts with the formation of Cs{sub 2}[(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)](H{sub 2}O) crystals, its subsequent dissolution and formation of Cs{sub 2}[(UO{sub 2}){sub 2}(SeO{sub 4}){sub 3}]. The information-based structural complexity calculations for these two phases support the rule that more topologically complex structures form at the latest stages of crystallization. - Graphical abstract: Nine phases representing the Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se) solid solution series with variable amount of S and Se have been prepared by isothermal evaporation from aqueous solutions and characterized using a number of experimental and theoretical techniques. No immiscibility is observed between the pure sulfate and selenate compounds. The Se-for-S substitution in tetrahedral sites is highly selective with smaller S{sup 6+} cation showing a strong preference for the more tightly bonded 4-connected site. - Highlights: • Single crystals of novel mixed sulfate-selenate uranyl oxysalts were prepared by evaporation method. • Topological analysis and information-based complexity calculations were used for structure description. • The selective Se-for-S substitution was observed. • Evolution of phase formation in the aqueous Cs{sup +}–UO{sub 2}{sup 2+}–SO{sub 4}{sup 2–}–SeO{sub 4}{sup 2–} system was analyzed.},
doi = {10.1016/J.JSSC.2017.02.005},
journal = {Journal of Solid State Chemistry},
number = ,
volume = 248,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2017},
month = {Sat Apr 15 00:00:00 EDT 2017}
}
  • {alpha}-CsPbBi{sub 3}Se{sub 6} (I), {beta}-CsPbBi{sub 3}Se{sub 6} (II), RbPbBi{sub 3}Se{sub 6} (III), KPbBi{sub 3}Se{sub 6} (IV), CsPbBi{sub 3}S{sub 6} (V), and RbPbBi{sub 3}S{sub 6} (VI) were synthesized by the polychalcogenide flux method. {alpha}-CsPbBi{sub 3}Se{sub 6} was obtained at 720 C and crystallizes in the space group Pnma (No. 62) with a = 23.564(6) {angstrom}, b = 4.210(2) {angstrom}, c = 13.798(3) {angstrom} at room temperature. Final R/R{sub w} = 3.0/3.6%. In this compound, parallel NaCl-type Pb/Bi/Se columns with rectangularly shaped cross-sections are interconnected by edge sharing to build a 3-D tunnel framework with Cs atoms located inside the tunnels. Themore » hexagonal plates of {beta}-CsPbBi{sub 3}Se{sub 6} were obtained at 400 C and crystallize in the space group P6{sub 3}/mmc (No. 194) with a = 4.213(2) {angstrom}, c = 25.22(1) {angstrom}, {gamma} = 120 at {minus}100 C. Final R/R{sub w} = 4.2/4.7%. APbBi{sub 3}Se{sub 6} (A = Rb, K) and APbBi{sub 3}S{sub 6} (A = Cs, Rb) are isostructural with {beta}-CsPbBi{sub 3}Se{sub 6} and their hexagonal cell parameters were obtained at room temperature. The structure is composed of negatively charged Bi{sub 2}Te{sub 3}-type bilayers separated by alkali metals, which are distributed over two different crystallographic sites. The alkali metal ions are loosely packed in the interlayer space making them mobile. Topotactic ion-exchange reactions of two compounds, {beta}-CsPbBi{sub 3}Se{sub 6} and RbPbBi{sub 3}Se{sub 6}, were examined with LiI and NaI in the solid state and in aqueous solution. Prolonged water contact of the hexagonal compounds leads to decomposition and leaching of alkali metal and Pb{sup 2+} ions. Electrical conductivity and thermopower measurements for single crystals of I, II, and III show n-type semiconductor behavior with 0.6, 0.3, and 0.3 S/cm and {minus}730, {minus}550, and {minus}560 {micro}V/K at room temperature, respectively. The optical band gaps of all compounds range from 0.27 to 0.89 eV. Thermal properties of the compounds are reported.« less
  • The electrophysical and photoelectric characteristics of ternary compounds A/sup I/BiS/sub 2/, A/sup I/BiSe/sub 2/, and A/sup I/Bi/sub 3/S/sub 5/ (A/sup I/ - Li, Na, K, Rb, Cs) were studied. It was established that the conductivities and melting points decrease and the thermo-emfs and forbidden band widths increase with increase in the atomic number of the alkali metal in the compounds A/sup I/BiS/sub 2/(Se/sub 2/). The discovered relationship is due to the change in the ionic component of the chemical bond.
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  • We studied the normal and superconducting states of the title compounds by measuring the conductivity and magnetization of single crystals and powder samples. From the upper and lower critical fields we deduced the characteristic lengths and thermodynamical fields. These results are borne out by our specific-heat measurements. We recognize in these compounds many features of the Chevrel-phase superconductors, including very small coherence lengths and strong-coupling-like effects. However, we show that the electron system is much more anisotropic and still less delocalized in these materials where the Mo{sub 6}Se{sub 8} clusters have condensed in Mo{sub 6{ital n}}Se{sub 6{ital n}+2} finite chains.more » This condensation is accompanied by an enhancement of the magnetic response whereas the lengthening of the chains leads to a counteracting reduction of the density of carriers. This indicates that superconductivity is built upon highly correlated molecular states. Reviewing the available data on the other Chevrel-cluster-based superconductors confirms this picture and suggests that the small coherence lengths reflect the local character of the electron pairing. This comparison also shows that forming finite chains of Mo{sub 6}Se{sub 8} clusters makes the electron correlations more repulsive and pushes the electron system near the borderline between superconductivity and magnetism. In this respect these compounds could provide valuable complementary information on issues which are at the center of the research upon high-{ital Y}{sub {ital c}} superconductivity.« less