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Research has been conducted on the vanadyl pyrophosphate' large transparent blue crystals. The study of their growth from a phosphorus pentoxide flux and of their single-crystal X-ray structure is presented.

The reaction enthalpies of the complexes (RPNP)Rh(COE) ((RPNP) = N(SiMe2CH2PPh2)2, N(SiMe2CH2PPr2)2; COE = cyclooctene) with a series of phosphine ligands and CO were obtained through solution calorimetry. These systems prefer coordination of strong pi-acceptor/weak sigma-donor ligands. Findings indicated that the significance of reorganization energies in thermodynamic studies of metal-ligand bonding, particularly in the presence of synergistic bonding involving sigma-donor, pi-donor and pi-acceptor ligands, interacting through shared metal orbitals.

The air-stable crystalline carbene 1,3-dimesityl-4,5-dichloroimidazol-2-ylidene (2) was formed through the chlorination of 1,3-dimesitylimidazol-2-ylidene (1) by carbon tetrachloride. The physical and spectroscopic characteristics were investigated. Further reaction of 2 with carbon tetrachloride was found to cause the reduction of CCl4 to dichlorocarbene. The tellurones derived from 1 and 2 were synthesized and compared.

The carbene-pnictinidene adducts of phenylphosphinidene, phenyllarsinidene, (trifluoromethyl)phosphinidene and (pentafluorophenyl)arsinidene with 1,3-dimesityllimidazol-2-ylidene are described. The formation of these adducts is via the direct reaction of a stable nucleophilic carbene with the corresponding pnictinidene cyclic oligomers. The adducts have strongly polarized pnictinidene-carbene bonds and are best described as coordination complexes between the singlet pnictinidenes and the nucleophilic carbene.

This work presents an assessment of the applicability of existing benchmark critical experiments to the criticality safety code validation for a large-capacity high-assay low-enriched uranium (HALEU) transportation package concept. Numerous next-generation nuclear reactor designs require HALEU fuel, which is characterized by an enrichment between 5 and 20 wt% 235U. The U.S. Department of Energy (DOE) has proposed to recover and downblend highly enriched uranium from DOE-owned used nuclear fuel to accelerate the demonstration of commercially viable microreactor technologies. One element of the infrastructure needed to demonstrate HALEU-fueled reactors is the ability to safely transport enriched product to be used for fuel fabrication. There is uncertainty as to whether existing critical benchmark experiment data are sufficient to support criticality safety code validation for HALEU transportation applications. The anticipated chemical form of the HALEU in the proposed transportation concept is UO2 with 20 wt% 235U/U. The concept uses a combination of an existing transportation packaging design and a novel basket design, including borated aluminum flux traps. The basket provides space for 18 reusable, stainless steel canisters that contain the HALEU. In 10 CFR 71, normal conditions of transport (NCTs) and hypothetical accident conditions (HACs) are defined for fissile material transportation packages. NCT and HAC KENO-VI models of the transportation package were developed using the Standardized Computer Analyses for Licensing Evaluation (SCALE) 6.2.3 computer code package, and optimum moderation conditions were determined using the SCALE SAMPLER sequence. The SCALE Tools for Sensitivity and Uncertainty Analysis Methodology Implementation (TSUNAMI) sequences were then used to compare the neutronic characteristics of 1584 International Criticality Safety Benchmark Evaluation Project benchmark critical experiments with the NCT and HAC HALEU transportation models. The TSUNAMI integral correlation coefficient ck was the criterion used to rank neutronic similarity. Thirty-four experiments were identified as similar (ck ≥ 0.9) to the NCT model, and 55 experiments were identified as similar to the HAC model. Hundreds of experiments were also identified as at least marginally similar (ck ≥ 0.8) to both models. The results indicate that additional critical experiments are unlikely to be needed to support HALEU transportation criticality safety analyses for package concepts similar to the concept package analyzed. [ABSTRACT FROM AUTHOR]

Research has been conducted on the mononuclear monohydridoiridate monoanions. The synthesis of these complexes, their X-ray structures and solution behavior are described.