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EXAFS provides the capability to interrogate nanoparticle (NP) structure in atomistic detail without relying on long‐range crystallinity. There is a limitation in that EXAFS provides averaged structural information, making it difficult to separate a small amount of heterogeneous structure from bulk. In this work, models were developed to extract surface‐specific information from conventional EXAFS measurements collected on UO2 NPs of varying size. Specifically, the surface terminating species of UO2 NPs was determined from comparison of coordination numbers with geometric models while the origin of static disorder was interrogated from user‐defined simulations. Results show that the degree of oxygenation on the NP surface does not significantly deviate from bulk surface and that static disorder is highly enhanced in NP surface layers but cannot be attributed to surface relaxation effects alone. The approach described herein has the potential to be adapted to a range of inorganic NP systems to interrogate surface structure. [ABSTRACT FROM AUTHOR]

Soft X‐ray spectromicroscopy at the O K‐edge, U N4,5‐edges and Ce M4,5‐edges has been performed on focused ion beam sections of spent nuclear fuel for the first time, yielding chemical information on the sub‐micrometer scale. To analyze these data, a modification to non‐negative matrix factorization (NMF) was developed, in which the data are no longer required to be non‐negative, but the non‐negativity of the spectral components and fit coefficients is largely preserved. The modified NMF method was utilized at the O K‐edge to distinguish between two components, one present in the bulk of the sample similar to UO2 and one present at the interface of the sample which is a hyperstoichiometric UO2+x species. The species maps are consistent with a model of a thin layer of UO2+x over the entire sample, which is likely explained by oxidation after focused ion beam (FIB) sectioning. In addition to the uranium oxide bulk of the sample, Ce measurements were also performed to investigate the oxidation state of that fission product, which is the subject of considerable interest. Analysis of the Ce spectra shows that Ce is in a predominantly trivalent state, with a possible contribution from tetravalent Ce. Atom probe analysis was performed to provide confirmation of the presence and localization of Ce in the spent fuel. [ABSTRACT FROM AUTHOR]

Homoleptic uranium(IV) amidate complexes have been synthesized and applied as single‐source molecular precursors for the chemical vapor deposition of UO2 thin films. These precursors decompose by alkene elimination to give highly crystalline phase‐pure UO2 films with an unusual branched heterostructure. UO2 nanotree: Volatile uranium(IV) amidate complexes are used as single‐source molecular precursors to uranium oxide films. Chemical vapor deposition (CVD) of these single‐source precursors yields crystalline, phase‐pure UO2 films with a fir tree‐like microstructure and a high surface area. [ABSTRACT FROM AUTHOR]

Single crystals of the title compounds are synthesized by solid state reactions of the elements in an ACl flux (A: Cs, K, Rb) (Ar, silica tubes, 1073-1123 K, 96-168 h). [ABSTRACT FROM AUTHOR]

The geometric features of the title compound, [Sc(C5Me5)2(C4H11Si)], are similar to those found in related monomeric organometallic scandium compounds. It is of inter­est with respect to related systems which have achieved catalytic metathesis of olefins with methane. [ABSTRACT FROM AUTHOR]

Reaction of dichloridotetra-kis(dimethyl sulfoxide)ruthenium(II) and N-[3,5-di-tert-butyl-2-(trimethyl-silyl-oxy)benz-yl]-N,N-bis-(2-pyridylmeth-yl)amine (BPPA-TMS) affords the thermodynamic product cis,fac-[RuCl(2)(BPPA-TMS)(DMSO)] and kinetic product trans,mer-[RuCl(2)(BPPA-TMS)(DMSO)]. The title complex, [RuCl(2)(C(30)H(43)N(3)OSi)(C(2)H(6)OS)]·2CH(2)Cl(2), crystallizes as a dichloro-methane disolvate, with two formula units in the asymmetric unit. The complex exhibits a distorted-octa-hedral geometry about the low spin d(6) Ru(II) center. The BPPA-TMS ligand is coordinated in a facial fashion, with the DMSO ligand cis to the aliphatic nitro-gen atom of the BPPA-TMS ligand. One of the two dichloromethane solvate molecules is disordered over two positions in a 0.695:0.305 ratio.