TY - JOUR

T1 - Selective Se-for-S substitution in Cs-bearing uranyl compounds

AU - Gurzhiy, V.V.

AU - Tyumentseva, O.S.

AU - Krivovichev, S.V.

AU - Tananaev, I.G.

PY - 2017/4/1

Y1 - 2017/4/1

N2 - 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 Cs2[(UO2)2(TO4)3] (T= S, Se), which crystallizes in tetragonal system, P-421m, a =9.616(1)–9.856(2), c =8.105(1)–8.159(1) Å, V =749.6(2)–792.5(3) Å3. Nine phases with variable amount of S and Se have been structurally characterized. The structures of the Cs2[(UO2)2(TO4)3] (T= S, Se) compounds are based upon the [(UO2)2(TO4)3]2- layers of corner-sharing uranyl pentagonal bipyramids and TO4 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 S6+ cation showing a strong preference for the more tightly bonded T2 site. Crystallization in the pure Se system starts with the formation of Cs2[(UO2)(SeO4)2(H2O)](H2O) crystals, its subsequent dissolution and formation of Cs2[(UO2)2(SeO4)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.

AB - 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 Cs2[(UO2)2(TO4)3] (T= S, Se), which crystallizes in tetragonal system, P-421m, a =9.616(1)–9.856(2), c =8.105(1)–8.159(1) Å, V =749.6(2)–792.5(3) Å3. Nine phases with variable amount of S and Se have been structurally characterized. The structures of the Cs2[(UO2)2(TO4)3] (T= S, Se) compounds are based upon the [(UO2)2(TO4)3]2- layers of corner-sharing uranyl pentagonal bipyramids and TO4 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 S6+ cation showing a strong preference for the more tightly bonded T2 site. Crystallization in the pure Se system starts with the formation of Cs2[(UO2)(SeO4)2(H2O)](H2O) crystals, its subsequent dissolution and formation of Cs2[(UO2)2(SeO4)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.

U2 - 10.1016/j.jssc.2017.02.005

DO - 10.1016/j.jssc.2017.02.005

M3 - Article

VL - 248

SP - 126

EP - 133

JO - Journal of Solid State Chemistry

JF - Journal of Solid State Chemistry

SN - 0022-4596

IS - 1 April

ER -