Topologically and geometrically flexible structural units in seven new organically templated uranyl selenates and selenite–selenates

Gurzhiy, Vladislav V.; Kovrugin, Vadim M.; Tyumentseva, Olga S.; Mikhaylenko, Pavel A.; Krivovichev, Sergey V.; Тананаев, И. Г.

doi:10.1016/j.jssc.2015.04.040

Cited by 21 publications

(10 citation statements)

References 57 publications

(43 reference statements)

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“…This type of topology has three-connected sulfate tetrahedra with the fourth non-shared vertex arranged up or down relative to the plane of the layer. This variability gives rise to geometric isomers with various orientations of the sulfate polyhedra (Krivovichev & Burns, 2003;Krivovichev et al, 2005;Gurzhiy et al, 2015). To identify and classify the isomers of this topological type, their orientation matrices should be determined.…”

Section: Topological and Structural Complexitymentioning

confidence: 99%

Structural complexity of natural uranyl sulfates

Gurzhiy

Plášil

2019

Acta Crystallogr Sect B

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Uranyl sulfates, including those occurring in Nature (∼40 known members), possess particularly interesting structures. They exhibit a great dimensional and topological diversity of structures: from those based upon clusters of polyhedra to layered structures. There is also a great variability in the type of linkages between U and S polyhedra. From the point of view of complexity of those structures (measured as the amount of Shannon information per unit cell), most of the natural uranyl sulfates are intermediate (300–500 bits per cell) to complex (500–1000 bits per cell) with some exceptions, which can be considered as very complex structures (>1000 bits per cell). These exceptions are minerals alwilkinsite‐(Y) (1685.95 bits per cell), sejkoraite‐(Y) (1859.72 bits per cell), and natrozippeite (2528.63 bits per cell). The complexity of these structures is due to an extensive hydrogen bonding network which is crucial for the stability of these mineral structures. The hydrogen bonds help to propagate the charge from the highly charged interlayer cations (such as Y3+) or to link a high number of interlayer sites (i.e. five independent Na sites in the monoclinic natrozippeite) occupied by monovalent cations (Na+). The concept of informational ladder diagrams was applied to the structures of uranyl sulfates in order to quantify the particular contributions to the overall informational complexity and identifying the most contributing sources (topology, real symmetry, interlayer bonding).

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Section: Topological and Structural Complexitymentioning

confidence: 99%

Structural complexity of natural uranyl sulfates

Gurzhiy

Plášil

2019

Acta Crystallogr Sect B

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“…Next compound, 42 [56], got into the review with a large tolerance. There are three nonequivalent positions of Se in the structure, only one of which was occupied by both Se(VI) and Se(IV), and the amount of the latter is very small (~0.07 per formula unit).…”

Section: Topological Analysismentioning

confidence: 99%

“…The crystal structures of three organically templated compounds, 43 [57], 44, and 45 [56], are based upon the layers with U:Se (Figure 2i,j). This topology of inorganic complexes is typical for uranyl selenite-selenates but has also been observed in some pure uranyl selenates, for instance, Rb 4 [(UO 2 ) 3 (SeO 4 ) 5 (H 2 O)] [79].…”

Section: Topological Analysismentioning

confidence: 99%

Crystal Chemistry and Structural Complexity of Natural and Synthetic Uranyl Selenites

et al. 2019

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Comparison of the natural and synthetic phases allows an overview to be made and even an understanding of the crystal growth processes and mechanisms of the particular crystal structure formation. Thus, in this work, we review the crystal chemistry of the family of uranyl selenite compounds, paying special attention to the pathways of synthesis and topological analysis of the known crystal structures. Comparison of the isotypic natural and synthetic uranyl-bearing compounds suggests that uranyl selenite mineral formation requires heating, which most likely can be attributed to the radioactive decay. Structural complexity studies revealed that the majority of synthetic compounds have the topological symmetry of uranyl selenite building blocks equal to the structural symmetry, which means that the highest symmetry of uranyl complexes is preserved regardless of the interstitial filling of the structures. Whereas the real symmetry of U-Se complexes in the structures of minerals is lower than their topological symmetry, which means that interstitial cations and H 2 O molecules significantly affect the structural architecture of natural compounds. At the same time, structural complexity parameters for the whole structure are usually higher for the minerals than those for the synthetic compounds of a similar or close organization, which probably indicates the preferred existence of such natural-born architectures. In addition, the reexamination of the crystal structures of two uranyl selenite minerals guilleminite and demesmaekerite is reported. As a result of the single crystal X-ray diffraction analysis of demesmaekerite, Pb 2 Cu 5 [(UO 2 ) 2 (SeO 3 ) 6 (OH) 6 ](H 2 O) 2 , the H atoms positions belonging to the interstitial H 2 O molecules were assigned. The refinement of the guilleminite crystal structure allowed the determination of an additional site arranged within the void of the interlayer space and occupied by an H 2 O molecule, which suggests the formula of guilleminite to be written as Ba 3 . occurrence is limited to just a few localities. First, these are Musonoi and Shinkolobwe mines in DR Congo [6], two of the minerals were only found in the Repete mine (San Juan County, Utah, USA) [5], and a few more occurrences in Europe could be mentioned (small uranium deposit Zálesí in the Czech Republic, Liauzun in France, and La Creusaz U prospect in Switzerland) [8]. Nevertheless, apart from mineralogy, uranyl selenites are of great interest from the geochemical and radiochemical points of view. It is known that fission products contain 53 g per ton [9] of long-lived 79 Se isotope with a half-life of 1.1 × 10 6 years [10] after three years of nuclear fuel irradiation in the reactor. Thus, an understanding of the processes of mineral formation in nature and their synthetic analogs in laboratories can help in the processing of nuclear wastes. Crystal chemical and structural investigations are key points in such a material's scientific studies due to the essential knowledge of how the variation in the chemical composi...

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“…The influence of the degree of hydration has been demonstrated to play a subtle but significant role in the formation of thorium nitrates [56] as well as uranium and neptunium nitrates [17] where changes to the number of H 2 O units present can lead to variability in structure formation often modulated through the presence of specific counter ions present. Accordingly, the subtle structural variation between Rb 2 [ [59] that such a configuration can lead to geometric isomerism occurring in the orientation of the sheets in these structures. It is noteworthy then that, through a variety of different synthesis/formation means, e.g., natural mineral formation, hydrothermal methods, or organic templating, that similar topological products can be obtained.…”

Section: Resultsmentioning

confidence: 99%

The Role of Acidity in the Synthesis of Novel Uranyl Selenate and Selenite Compounds and Their Structures

et al. 2021

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Herein, the novel uranyl selenate and selenite compounds Rb2[(UO2)2(SeO4)3], Rb2[(UO2)3(SeO3)2O2], Rb2[UO2(SeO4)2(H2O)]·2H2O, and (UO2)2(HSeO3)2(H2SeO3)2Se2O5 have been synthesized using either slow evaporation or hydrothermal methods under acidic conditions and their structures were refined using single crystal X-ray diffraction. Rb2[(UO2)2(SeO4)3] synthesized hydrothermally adopts a layered 2D tetragonal structure in space group P42/ncm with a = 9.8312(4) Å, c = 15.4924(9) Å, and V = 1497.38(15) Å, where it consists of UO7 polyhedra coordinated via SeO4 units to create units UO2(SeO4)58− moieties which interlink to create layers in which Rb+ cations reside in the interspace. Rb2[(UO2)3(SeO3)2O2] synthesized hydrothermally adopts a layered 2D triclinic structure in space group P1¯ with a = 7.0116(6) Å, b = 7.0646(6) Å, c = 8.1793(7) Å, α = 103.318(7)°, β = 105.968(7)°, γ = 100.642(7)° and V = 365.48(6) Å3, where it consists of edge sharing UO7, UO8 and SeO3 polyhedra that form [(UO2)3(SeO3)2O2] layers in which Rb+ cations are found in the interlayer space. Rb2[UO2(SeO4)2(H2O)]·2H2O synthesized hydrothermally adopts a chain 1D orthorhombic structure in space group Pmn21 with a = 13.041(3) Å, b = 8.579(2) Å, c = 11.583(2) Å, and V = 1295.9(5) Å3, consisting of UO7 polyhedra that corner share with one H2O and four SeO42− ligands, creating infinite chains. (UO2)2(HSeO3)2(H2SeO3)2Se2O5 synthesized under slow evaporation conditions adopts a 0D orthorhombic structure in space group Cmc21 with a = 28.4752(12) Å, b = 6.3410(3) Å, c = 10.8575(6) Å, and V = 1960.45(16) Å3, consisting of discrete rings of [(UO2)2(HSeO3)2(H2SeO3)2Se2O5]2. (UO2)2(HSeO3)2(H2SeO3)2Se2O5 is apparently only the second example of a uranyl diselenite compound to be reported. A combination of single crystal X-ray diffraction and bond valance sums calculations are used to characterise all samples obtained in this investigation. The structures uncovered in this investigation are discussed together with the broader family of uranyl selenates and selenites, particularly in the context of the role acidity plays during synthesis in coercing specific structure, functional group, and topology formations.

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Topologically and geometrically flexible structural units in seven new organically templated uranyl selenates and selenite–selenates

Cited by 21 publications

References 57 publications

Structural complexity of natural uranyl sulfates

Structural complexity of natural uranyl sulfates

Crystal Chemistry and Structural Complexity of Natural and Synthetic Uranyl Selenites

The Role of Acidity in the Synthesis of Novel Uranyl Selenate and Selenite Compounds and Their Structures

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