Vibrational spectroscopy of a crystallographically unsettled uranyl carbonate: Structural impact and model

Faulques, Eric; Perry, Dale L.; Kalashnyk, Nataliya

doi:10.1016/j.vibspec.2018.10.004

Cited by 8 publications

(3 citation statements)

References 26 publications

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“…The presence of low-energy OH stretching modes in sample A (and B) is again attributed to the hydrogen bonding between equatorial hydroxide groups and interlayer water molecules. 25,27,63 The high-energy shoulder on the OH stretching peak in sample C at 3480 cm −1 and the weak H 2 O bending mode at 1621 cm −1 indicate the existence of some remaining crystallographic water molecules in sample C, consistent with the determination that sample C still contains approximately 10% synthetic metaschoepite by weight (Table 2). A small peak in the IR spectrum of sample C at 1540 cm −1 is consistent with a weak peak at 1532 cm −1 observed in the IR spectrum of stoichiometric α-UO 2 (OH) 2 by Hoekstra and Siegel.…”

Section: ■ Discussionmentioning

confidence: 99%

Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

et al. 2019

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We confirm that synthetic uranyl hydroxide hydrate metaschoepite [(UO)24O(OH)6]·5H2O is unstable against dehydration under dry conditions, and we present a structural and vibrational spectroscopic study of synthetic metaschoepite and its ambient temperature dehydration product. Complementary structural (X-ray diffraction and neutron diffraction) and vibrational spectroscopic techniques (Raman spectroscopy, infrared spectroscopy, and inelastic neutron scattering) are used to probe different components of these species. Analysis of the dehydration product suggests that it contains both pentagonally coordinated and hexagonally coordinated uranyl ions, necessitating that some uranyl ions undergo a coordination change during the dehydration of pentagonally coordinated metaschoepite. Vibrational spectra of metaschoepite and its dehydration product are interpreted with power spectra generated from ab initio molecular dynamics trajectories, allowing assignment of all major features. We identify the uranyl symmetric stretching modes of the four distinct uranyl ions in synthetic metaschoepite and clarify the assignment of lower energy Raman modes in both structures. The coanalysis of experimental and computational data reveals a strong coupling between the uranyl stretching modes and hydroxide bending modes in the anhydrous structure, leading to the presence of several high-energy combination bands in the inelastic neutron scattering data.

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Section: ■ Discussionmentioning

confidence: 99%

Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

et al. 2019

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“…The local extremum at E = −0.11 eV; λ = 11.3 μm (ṽ = 887 cm −1 ) is specific to calcium carbonate ions [ 32 , 40 ]. The local extremum at E = −0.1112 eV or (λ = 11.3 μm; ṽ = 887 cm −1 ) is typical for calcium conductivity [ 41 , 42 ].…”

Section: Resultsmentioning

confidence: 99%

Research of Water Molecules Cluster Structuring during Haberlea rhodopensis Friv. Hydration

Ignatov

Huether²,

Neshev

et al. 2022

Plants

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Gesneriaceae plant family is comprised of resurrection species, namely Boea hygrometrica and Paraboea rufescens, that are native to the Southeast Asia and Haberlea rhodopensis, Ramonda myconi, and Ramonda serbica, which are mainly found in the Balkan Peninsula. Haberlea rhodopensis is known to be able to survive extreme and prolonged dehydration. Study was carried out after the dried plant Haberlea rhodopensis Friv. had been hydrated and had reached its fresh state. Two juice samples were collected from the plant blossom: The first sample was prepared with 1% filtered water through a patented EVOdrop device. Then the sample was saturated with hydrogen with EVOdrop booster to a concentration of 1.2 ppm, pH = 7.3, ORP = −390 mV. This first sample was prepared with filtered tap water from Sofia, Bulgaria. The second sample, which was a control one, was developed with tap water from Sofia, Bulgaria, consisting of 1% solutions of Haberlea rhodopensis. A study revealed that during the drying process in H. rhodopensis the number of free water molecules decreases, and water dimers are formed. The aim of our study was to determine the number of water molecules in clusters in 1% solutions of hydrated H. rhodopensis plants. Results were analyzed according to the two types of water used in the experiment. Th EVOdrop device is equipped with an ultranano membrane and rotating jet nozzle to create a vortex water and saturation thanks to a second device EVObooster to obtain hydrogen-rich water. In the current study Hydrogen-rich water is referred to as Hydrogen EVOdrop Water (HEW). Research was conducted using the following methods—spectral methods non-equilibrium energy spectrum (NES) and differential non-equilibrium energy spectrum (DNES), mathematical models, and study of the distribution of water molecules in water clusters. In a licensed Eurotest Laboratory, the research of tap water before and after flowing through the EVOdrop device was proven. Studies have been carried out on the structuring of water molecule clusters after change of hydrogen bond energies. The restructuring comes with rearrangement of water molecules by the energy levels of hydrogen bonds. Local extrema can be observed in the spectrum with largest amount of water molecules. The structural changes were tested using the NES and DNES spectral methods. The conducted research proved that the application of EVOdrop device and EVObooster changes the parameters of water to benefit hydration and health.

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“…This spectrum contains peaks of N-H bond vibrations in NH4 + at 1393 and 2900-3300 cm -1 [37] as well as the of the carbonate anion at 1471 cm -1 . The CO3 2− vibrations overlap with the intense peak of the ammonium cation vibrations and contribute to the broadened shoulder at 1000-1200 cm −1 [36,38]. Peaks at 2336 and 2360 cm −1 are due to atmospheric CO2.…”

Section: Vibrational Spectroscopymentioning

confidence: 97%

Crystal Structure of Mixed Np(V)-Ammonium Carbonate

et al. 2022

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This work presents details of the synthesis, properties and structure of a novel neptunium carbonate (NH4)[NpO2CO3], a member of the M[AnO2CO3] (M = K, (NH4), Rb, Cs) class of compounds. Carbonates play an important role in the migration of actinides in the environment, and thus are relevant for handling and disposal of radioactive wastes, including spent nuclear fuel and vitrified raffinates. Knowledge of the crystallographic structure of these compounds is important for models of the environmental migration behavior based on thermodynamic descriptions of such chemical processes. (NH4)[NpO2CO3] crystals were obtained during long-term hydrothermal treatment of Np(VI) in aqueous ammonia at 250 °C. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) show that a single-phase sample containing only Np(V) was obtained. Structural features of (NH4)[NpO2CO3] were elucidated from single crystal X-ray diffraction and confirmed by vibrational spectroscopy. The results obtained are of interest both for fundamental radiochemistry and for applied problems of the nuclear fuel cycle.

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Vibrational spectroscopy of a crystallographically unsettled uranyl carbonate: Structural impact and model

Cited by 8 publications

References 26 publications

Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

Research of Water Molecules Cluster Structuring during Haberlea rhodopensis Friv. Hydration

Crystal Structure of Mixed Np(V)-Ammonium Carbonate

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