A5031693146- Radioactive element chemistry and processing
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Lanthanide and Transition Metal Complexes
- Nuclear Materials and Properties
- Chemical Synthesis and Characterization
- Polyoxometalates: Synthesis and Applications
- Radioactive contamination and transfer
- Crystallography and molecular interactions
- Nuclear materials and radiation effects
- Nuclear reactor physics and engineering
- Crystal Structures and Properties
- Analytical chemistry methods development
- Radioactivity and Radon Measurements
- Electrochemical Analysis and Applications
- Zeolite Catalysis and Synthesis
- Vanadium and Halogenation Chemistry
- Radiopharmaceutical Chemistry and Applications
- Geochemistry and Elemental Analysis
- Crystal structures of chemical compounds
- Spectroscopy and Quantum Chemical Studies
- Chemical Thermodynamics and Molecular Structure
- Solid-state spectroscopy and crystallography
- Mine drainage and remediation techniques
- Enhanced Oil Recovery Techniques
University of Notre Dame
2015-2024
Notre Dame of Dadiangas University
2015-2017
Argonne National Laboratory
2007
Waste not: Actinyl nanospheres self-assembled from alkaline solutions have been shown to be composed of 24, 28, and 32 actinyl peroxide polyhedra (for example, see picture the uranyl (U-28)). The represent a new class polyoxometalates, their formation in nuclear waste may an impact on mobility actinides environment.
C U soon: Clusters containing 60, 44, and 36 uranyl peroxide hydroxide polyhedra (see picture) adopt fullerene topologies of maximum symmetry. The largest these, denoted U60, is topologically identical to C(60) with no pentagonal adjacencies the highest possible U44 adopts topology symmetry rather than that lowest number adjacencies.
The Fukushima-Daiichi nuclear accident brought together compromised irradiated fuel and large amounts of seawater in a high radiation field. Based on newly acquired thermochemical data for series uranyl peroxide compounds containing charge-balancing alkali cations, here we show that nanoscale cage clusters as many 60 ions, bonded through hydroxide bridges, are likely to form solution or precipitates under such conditions. These species will enhance the corrosion damaged and, being...
Uranyl peroxide polyhedra are known to self-assemble into complex closed clusters with fullerene and other topologies containing as many 60 polyhedra. Here 20 uranyl pentagonal triperoxides have been isolated characterized that assume the smallest possible topology consisting only of 12 pentagons. Oxalate has used crystallize fragments larger clusters, these structures indicate U−O2−U dihedral angle is inherently bent. Such bending thought be essential in directing self-assembly clusters.
Despite potential applications in advanced nuclear energy systems, nanoscale control of uranium materials is its infancy. In hexavalent state, U occurs as (UO2)2+ uranyl ions that are coordinated by various ligands to give square, pentagonal, or hexagonal bipyramids. Creation and design nanostructured requires interruption the tendency bipyramids share equatorial edges form infinite sheets occur extended structures. Where a bidentate peroxide group bridges bipyramids, configuration...
Three unique thorium dimeric compounds have been crystallized from either direct hydrolysis of Th4+(aq)/HCl or titration Th(OH)4(am) with Th(NO3)4(aq) and their structures determined using single-crystal X-ray diffraction. The compound [Th2(micro2-OH)2(NO3)6(H2O)6]H2O (1) is identical to that identified previously by Johansson. Two additional unreported identified, [Th2(micro2-OH)2(NO3)4(H2O)8](NO3)2 (2) [Th2(micro2-OH)2Cl2(H2O)12]Cl4.2H2O (3). 1 crystallizes in the monoclinic space group...
Clusters built from 32 uranyl peroxide polyhedra self-assemble and crystallize within 15 min after combining nitrate, ammonium hydroxide, hydrogen in aqueous solution under ambient conditions. These novel crown-shaped clusters are remarkable that they form so quickly, have extraordinarily low solubility, with at least two distinct to hydroxyl ratios, very high yield. The clusters, which outer diameters of 23 Å, topologically consist eight pentagons four hexagons. Their rapid formation...
Strategies for interpreting mass spectrometric and Raman spectroscopic data have been developed to study the structure reactivity of uranyl peroxide cage clusters in aqueous solution. We demonstrate efficacy these methods using three best-characterized clusters, {U24}, {U28}, {U60}. Specifically, we show a correlation between uranyl-peroxo-uranyl dihedral bond angles position band symmetric stretching mode peroxo ligand, develop assignment ESI spectra that are generally applicable detecting...
Recent accidents resulting in worker injury and radioactive contamination occurred due to pressurization of uranium yellowcake drums produced the western U.S.A. The contained an X-ray amorphous reactive form oxide that may have contributed pressurization. Heating hydrated uranyl peroxides during situ mining can produce compound, as shown by powder diffraction material from impacted drums. Subsequently, studtite, [(UO2)(O2)(H2O)2](H2O)2, was heated laboratory. Its thermal decomposition a...
Bowl (U(16)) and crown-shaped clusters (U(20R) U(24R)) containing 16, 20, 24 uranyl peroxide polyhedra self-assemble in alkaline aqueous solution under ambient conditions. Structural analyses of crystallized provided details their topologies. Each contains hexagonal bipyramids which two cis edges are peroxide, with a third edge defined by OH groups, as well three peroxide. These the first open reported, they join growing family complex cluster topologies based on uranium that hold promise...
Abstract The critical gelation conditions observed in dilute aqueous solutions of multiple nanoscale uranyl peroxide molecular clusters are reported, the presence multivalent cations. This is dominantly driven by counterion‐mediated attraction. areas corresponding phase diagrams all appear similar locations, with a characteristic triangle shape outlining three boundary conditions, to cluster concentration, cation/cluster ratio, and degree counterion association increasing concentration....
Nicht vergeuden: Actinyl-Nanokugeln, die sich in alkalischen Lösungen bilden, bestehen aus 24, 28 und 32 Actinylperoxid-Polyedern (als Beispiel sind Uranylperoxid-Polyeder (U-28) gezeigt). Die Nanokugeln bilden eine neue Klasse von Polyoxometallaten, ihre Bildung Nuklearabfällen könnte einen Einfluss auf Mobilität Actinoiden der Umwelt haben.
Four self-assembling clusters of uranyl peroxide polyhedra have been formed in alkaline aqueous solutions and structurally characterized. These consist 28, 30, 36 44 exhibit complex new topologies. Each has a structure that contains topological squares, pentagons hexagons. Analysis possible topologies within boundary constraints indicates tendency for adoption higher symmetry these cases. Small angle X-ray scattering data demonstrated crystals one can be dissolved ultrapure water the remain...
Abstract Three uranyl sulfates, (C 6 H 20 N 4 )[(UO 2 ) (SO · (H O) ](H (TETAUS), 15 14 3 )(SO ](NO (TPUS), and K [(UO O)] O (KUS), two selenates, K(H O)[(UO (SeO O)](H (KUSe) (USe), were synthesized by slow evaporation of aqueous solutions at room temperature. TETAUS crystallizes in space group P -1, a = 6.7186(5) Å, b 9.2625(7) c 13.1078(9) α 72.337(2)°, β 89.198(2)°, γ 70.037(1)°, V 726.89(9) Å , Z 1. TPUS is triclinic, 6.9732(7) 13.569(1) 13.641(1) 111.809(2)°, 102.386(2)°, 93.833(2)°,...
Abstract Plutonium(IV) oxide nanoclusters represent an interesting scientific problem regarding structure‐function relationships and are also relevant to global concerns surrounding plutonium reprocessing, the remediation of plutonium‐contaminated soils, storage or disposal plutonium‐containing wastes. Here we report synthesis five unique Pu IV containing 38, 22, 16 metal centers capped only with inorganic ligands, such as chlorine water, which prevent formation extended PuO 2 structure. The...
Uranyl vanadate sulfate clusters isolated from a mixture of water and ionic liquid present structure intermediate between those typical transition metal polyoxometalates uranyl peroxide cage clusters.
Abstract Wahl der Nachbarn : Cluster mit 60, 44 und 36 Uranylperoxidhydroxid‐Polyedern (siehe Bild) nehmen Fullerentopologien von maximaler Symmetrie an. Der größte Cluster, U60, ist topologisch identisch C 60 (keine benachbarten Fünfecke, höchstmögliche Symmetrie). U44 hat eine Topologie anstelle einer niedrigsten Zahl benachbarter Fünfecke. magnified image
Uranium concentrations as high 2.94 × 105 parts per million (1.82 mol of U/1 kg H2O) occur in water containing nanoscale uranyl cage clusters. The anionic clusters, with diameters 1.5–2.5 nm, are charge-balanced by encapsulated cations, well cations within their electrical double layer solution. concentration uranium these systems is impacted the countercations (K, Li, Na), and molecular dynamics simulations have predicted distributions selected cases. Formation cages prevents hydrolysis...
The effects of radiation on a variety uranyl peroxide compounds were examined using γ-rays and 5 MeV He ions, the latter to simulate α-particles. studied materials studtite, [(UO2)(O2)(H2O)2](H2O)2, salt U60 cage cluster, Li44K16[(UO2)(O2)(OH)]60·255H2O, U60Ox30 oxalate Li12K48[{(UO2)(O2)}60(C2O4)30]·nH2O, U24Pp12 (Pp = pyrophosphate) pyrophosphate Li24Na24[(UO2)24(O2)24(P2O7)12]·120H2O. Irradiated powders characterized powder X-ray diffraction, Raman spectroscopy, infrared photoelectron...
We report a complex coacervate formed by 2.5 nm-diameter, rigid uranyl peroxide molecular cluster (Li
The family of cage clusters built by uranyl ions bridged through bidentate peroxide groups has been expanded incorporation 1-hydroxyethane-1,1-diphosphonic (etidronic) acid ligands. Six containing from 16 to 64 ions, as well eight 32 etidronic ligands have synthesized and characterized. Incorporation introduces both new cluster topologies organic functional this class nanoscale materials. anionic were crystallized aqueous solution under ambient conditions for structural characterization,...
Cation–cation interaction: A new 2 D sheet structure containing a side-on cation–cation interaction (CCI) has been synthesized and characterized (see figure). Unprecedentedly, no chelating ligands between the cations are present. The nature of ligand effects explored by using variety quantum chemical methods. spin–orbit-coupled ground state mixes singlet, triplet, quintet-pure spin states.