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At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Pu5Ir3 by Materials Project

Pu5Ir3 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. there are two inequivalent Pu sites. In the first Pu site, Pu is bonded in a 4-coordinate geometry to four equivalent Ir atoms. All Pu–Ir bond lengths are 2.94 Å. In the second Pu site, Pu is bonded in a 6-coordinate geometry to six Ir atoms. There are a spread of Pu–Ir bond distances ranging from 2.89–3.20 Å. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 10-coordinate geometry to eight equivalent Pu and two equivalent Ir atoms. Both Ir–Ir bond lengths are 2.79 Å. In the second Ir site, Ir is bonded in a 10-coordinate geometry to ten Pu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuAl3 by Materials Project

PuAl3 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Pu sites. In the first Pu site, Pu is bonded to twelve Al atoms to form PuAl12 cuboctahedra that share corners with six equivalent PuAl12 cuboctahedra, edges with six equivalent AlPu4Al8 cuboctahedra, faces with six equivalent AlPu4Al8 cuboctahedra, and faces with eight equivalent PuAl12 cuboctahedra. There are six shorter (3.04 Å) and six longer (3.06 Å) Pu–Al bond lengths. In the second Pu site, Pu is bonded to twelve Al atoms to form PuAl12 cuboctahedra that share corners with six equivalent AlPu4Al8 cuboctahedra, corners with nine equivalent PuAl12 cuboctahedra, edges with six equivalent AlPu4Al8 cuboctahedra, faces with three equivalent AlPu4Al8 cuboctahedra, and faces with seven PuAl12 cuboctahedra. There are a spread of Pu–Al bond distances ranging from 3.00–3.06 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to four Pu and six Al atoms. There are a spread of Al–Al bond distances ranging from 2.84–2.93 Å. In the second Al site, Al is bonded to four Pu and eight Al atoms to form distorted AlPu4Al8 cuboctahedra that share corners with four equivalent PuAl12 cuboctahedra, corners with six equivalent AlPu4Al8 cuboctahedra, edges with four equivalent AlPu4Al8 cuboctahedra, edges with six PuAl12 cuboctahedra, faces with four PuAl12 cuboctahedra, and faces with four equivalent AlPu4Al8 cuboctahedra. All Al–Al bond lengths are 3.06 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu5Rh3 by Materials Project

Pu5Rh3 crystallizes in the tetragonal P4/ncc space group. The structure is three-dimensional. there are two inequivalent Pu sites. In the first Pu site, Pu is bonded in a 4-coordinate geometry to four equivalent Rh atoms. All Pu–Rh bond lengths are 2.94 Å. In the second Pu site, Pu is bonded in a 6-coordinate geometry to six Rh atoms. There are a spread of Pu–Rh bond distances ranging from 2.87–3.22 Å. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 10-coordinate geometry to ten Pu atoms. In the second Rh site, Rh is bonded in a 10-coordinate geometry to eight equivalent Pu and two equivalent Rh atoms. Both Rh–Rh bond lengths are 2.80 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Particulate plutonium released from the Fukushima Daiichi meltdowns

Traces of Pu have been detected in material released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March of 2011; however, to date the physical and chemical form of the Pu have remained unknown. Here we report the discovery of particulate Pu associated with cesium-rich microparticles (CsMPs) that formed in and were released from the reactors during the FDNPP meltdowns. The Cs-pollucite-based CsMP contained discrete U(IV)O 2 nanoparticles, <~10 nm, one of which is enriched in Pu adjacent to fragments of Zr-cladding. The isotope ratios, 235 U/ 238 U, 240 Pu/ 239 Pu, and 242 Pu/ 239 Pu, of the CsMPs were determined to be ~0.0193, ~0.347, and ~0.065, respectively, which are consistent with the calculated isotopic ratios of irradiated-fuel fragments. Thus, considering the regional distribution of CsMPs, the long-distance dispersion of Pu from FNDPP is attributed to the transport by CsMPs that have incorporated nanoscale fuel fragments prior to their dispersion up to 230 km away from the Fukushima Daiichi reactor site.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2020

Mechanisms of Plutonium Redox Reactions in Nitric Acid Solutions

Plutonium (Pu) exhibits a complex redox behavior in acidic solutions due to its ability to adapt a wide range of oxidation states typically from +3 to +6 and the tendency for dynamic interconversion between the oxidation states that depends upon electrochemical potential, acid concentration and coordination environments. In particular, the accurate redox speciation of Pu in nitric acid solutions and mapping the interconversion between the various oxidation states mechanistically is challenging due to overlapping chemical and electrochemical reactions leading to significant experimental uncertainties. The last several decades have seen the extensive use of spectroscopic methods to identify and characterize Pu solution species in the various oxidation states. However, dynamic redox mobility of Pu has led to discrepancies among the relevant spectral databases for Pu in nitric acid solutions. This work utilizes a combination of voltammetry and controlled-potential in-situ vis–NIR spectroelectrochemistry to overcome these challenges, and map the interconversion between Pu species in +3, +4, and +6 oxidation states. This allowed elucidation of the mechanisms of the involved redox reactions and an in-depth understanding of the relative stability of the Pu oxidation states through mapping of the Pu redox processes as a function of redox potentials and nitric acid concentrations. The NIR-spectroelectrochemistry studies used to spectroscopically map the redox speciation of Pu as a function of oxidation potentials with varying HNO3 concentrations allows a new perspective into the plutonium redox transformations.

Chatterjee, Sayandev↗
DOE OSTI2026

Ion-Specific Effects on PuO 2 Nanoparticle Aggregation and Dissolution in Concentrated Electrolytes

Hydrolytic PuO 2 nanoparticles (NPs) are a dominant aqueous Pu-bearing phase in high ionic strength nuclear wastes, yet their reactivity in nonideal brines remains poorly constrained. We quantify how electrolyte identity and concentration control PuO 2 NP aggregation and ligand-assisted dissolution in acidic, high salinity solutions (NaCl, NaNO 3 , NaClO 4 , Na 2 SO 4 , Na 2 C 2 O 4 up to 5 M). A multitechnique workflow combining liquid scintillation counting (operationally defined aqueous [Pu]), scattering/electrokinetic measurements (aggregate size and zeta potential), and spectroscopy (UV–vis, XPS, Raman) resolves electrolyte-dependent partitioning between colloidal and molecular Pu species. Weakly coordinating anions (ClO 4 – , Cl – , NO 3 – ) largely preserve the (aggregated) nanoparticulate fraction but generate distinct dissolved species at high concentration, i.e., Pu(IV)–nitrato complexes in NaNO 3 and Pu(VI)–chloro complexes in NaCl. In contrast, stronger ligands substantially perturb PuO 2 NP stability: sulfate promotes partial dissolution to Pu(IV)–sulfate complexes at low concentration but reduces aqueous [Pu] at higher sulfate levels via secondary Pu(IV) sulfate formation, whereas oxalate drives strong dissolution to aqueous Pu–oxalate complexes. Aged NPs show similar trends with reduced aqueous fractions and more dominant aggregation mechanisms. In conclusion, these spectroscopically constrained speciation data provide a foundation for incorporating PuO 2 NP reactivity into thermodynamic and reactive transport models for high salinity waste and brine environments.

Aggregation↗
DOE OSTI2025

Caustic Neutralization and Precipitation of Acidic Dissolved Simulated Stainless Steel–Clad Plutonium and Plutonium/Uranium Nuclear Fuel

Simulated dissolved stainless steel (SS) clad Pu and Pu/U nuclear fuel in HNO 3 was neutralized to a free hydroxide (OH - ) concentration of 0.6 M. A thermal neutron poison, Gd, was added to the simulants at concentrations of either ~3 - 6 g/L or ~37 - 38 g/L. The supernate Pu concentration the day of neutralization ranged from 0.48 to 8.75 mg/L. The supernate Pu concentration of a simplified simulant neutralized to 0.6 M OH - above precipitated solids containing Pu was demonstrated to decrease over 18 days. A significant portion of precipitated Pu was found to be insoluble in 8 M HNO 3 at ambient temperature, but essentially quantitative Pu dissolution was achieved in 11.5 M HNO 3 /0.1 M KF at 100 °C. The difficulty in dissolving the Pu precipitate is believed to be due to the formation of refractory PuO 2 •xH 2 O during the neutralization process. Initial Gd concentrations of ~37 – 38 g/L were found to result in a greater Al precipitation when neutralized to 0.6 M OH - than initial Gd concentrations of ~3 – 6 g/L. Physical properties of the resultant slurries were measured and used to calculate limiting flowrates and slurry velocities by gravity only in transfer piping between the Savannah River Site’s H-Canyon Facility and the Concentration, Storage, and Transfer Facility (CSTF). These results were compared to calculated deposition velocities to predict if solids would settle during the transfer. The Newtonian model was found to be reasonable for each diluted slurry evaluated. Deposition velocities of Pu containing slurries are lower than nuclear fuel slurries primarily composed of U due to the high density of Pu solids. In conclusion, dilution of slurries reduces the margin between the slurry and deposition velocities due to the reduction in viscosity because higher viscous forces on the particles promote maintained suspension.

Actinide Neutralization↗
DOE OSTI2025

Separation of dilute plutonium(IV) from nitric acid solutions via Reillex HPQ anion exchange resin

Anion exchange is a common method for the separation of plutonium (Pu) in aqueous systems, providing high recovery and decontamination from impurities. Reillex HPQ anion exchange resin has been used around the Department of Energy complex in this application for decades but has typically been used for Pu feed concentrations greater than 1 g/L. It is desirable to recover Pu at more dilute concentrations from a dissolved used fuel or target element, for example. In this work, the performance of Reillex HPQ anion exchange resin was characterized with feed solutions of ca. 0.24 g/L Pu. A significant reduction in the performance of the resin was realized with this dilute concentration relative to a feed solution of 2.35 g/L Pu with similar feed flow rates and the same resin column, likely due to the increased driving force for mass transfer with a higher feed concentration. The maximum capacity of Reillex HPQ resin for Pu can be improved by reducing the flow rate and increasing the feed Pu concentration. Furthermore, the breakthrough point of Pu can be improved in the same manner and by increasing the resin bed height. Diffusion of Pu into the resin was illustrated to be the rate limiting step.

Plutonium separations↗
DOE OSTI2023

Dose reconstruction for plutonium-239 intakes at the Rocky Flats Plant

Purpose: The Rocky Flats (RF) Plant was a weapons manufacturing facility that operated from the early 1950s to 1989. Its primary missions were the production of plutonium (Pu) pits for thermonuclear weapons and the processing of retired weapons for Pu recovery. The purpose of this study was to estimate radiation doses to a cohort of 4499 RF workers from an intake of 239 Pu, the primary plutonium isotope handled at the site. Materials and methods: The latest biokinetic models of the International Commission on Radiological Protection, or site-specific variations of those models, were used to estimate 239 Pu intakes for each worker based on model fits to bioassay data often coupled with lung measurements. Results: Urinary excretion and lung retention data for most 239 Pu intakes could be fit reasonably well by a mixture of Pu dioxide and moderately soluble material. For some workers, better fits were obtained by application of other absorption types including Type S, 239 Pu nitrate, or pure 239 Pu dioxide, or by assuming intake via a wound. The lungs typically received the highest tissue doses, with fifty-year committed equivalent doses in the range of 0.5–1 Sv for 275 workers, 1–5 Sv for 115 workers, and greater than 5 Sv for 12 workers. Conclusions: RF was a unique site regarding a large number of lung measurements available for determining the appropriate absorption types for inhaled material. Further, this provided higher confidence in reconstructed 239 Pu doses than is generally gained from urinary data alone.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2022

CSEWG Meeting Minutes

Work has been done at LANL to validate various updated evaluations from ENDF/BVIII.1b0 including: Fe, Cu, Si, U, Pu. Continuous energy tables were processed with NJOY2016 and output to ACE files. For non-Pu legacy critical benchmarks, all calculations were within the experimental benchmark uncertainty, with some benchmarks having shown lower bias using ENDF/B-VIII.1b0. In HST systems, ENDF/B-VIII.0 shows reasonable results above the thermal leakage fraction. ENDF/B-VIII.0.1 is doing slightly worse than ENDF/B- VIII.0. b0.2 and it also includes a new 19 F evaluation, so more work is needed to examine its impact. 233 U thermal and intermediate bare and water-reflected benchmarks agree well with ENDF/B-VIII.0. From ENDF/B-VIII.0 to ENDF/B-VIII.0b0.1, HMF-007 C/E are increasing and the new 19 F evaluation is helping the HMF-007 cases containing Teflon which have historically had high C/E. The Pu legacy benchmark suite is within experimental uncertainty with the exception of THOR. The INDEN evaluation followed by LANL gave the lowest mean absolute bias, but it remains difficult to make a determination on which Pu evaluation is the best. INDEN performs slightly better for the JEZEBEL series, while the LANL Pu evaluation is better for THOR and flattop benchmarks. For the PMI benchmark series INDEN outperforms the LLNL evaluation. For the PST benchmark series ENDF/B-VIII.0 and LLNL Pu evaluations are better than the INDEN evaluation. C/E ratios for Jezebel and Godiva reaction rate ratios show all the Pu evaluations are very close to one another, making it again difficult to say which is best. When examining neutron reactor kinetics parameters, each Pu evaluation is once again very close. Each individual Pu evaluation seems to have advantages in their own applications.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Colloidal Behavior of Plutonium Oxide in Concentrated Electrolyte Solutions

The Hanford Site in Washington State manages legacy high-level radioactive waste streams that display major chemistry and engineering challenges, including the high salt levels and pH values that correspond to conditions under which many classical concepts describing chemical reactivity cannot be applied. One particular challenge that needs to be tackled at Hanford is that Pu concentrations, [Pu], in the soluble phases of the tank wastes are higher than expected based on the solubility of crystalline PuO2, which is widely accepted to be caused by the formation of PuO2 colloid, consisting of nano- to submicron-sized particles (PuO2 NPs). Fundamental research underpinning the behavior of PuO2 NPs under conditions not only relevant to the Hanford tank waste but at high ionic strength in general is needed to reliably predict the chemical reactivity of PuO2 NPs and develop engineering solutions to safely and efficiently process high-level radioactive waste into forms suitable for long-term storage. In this work, we study the behavior of PuO2 NPs (particle size ~100 nm) under high ionic strength conditions by reacting it with highly concentrated (up to 5 M) salt solutions. We explore different electrolyte compositions to elucidate the impact of different anions (NO3-, Cl-, ClO4-, SO42-, C2O42-, CO32-) on the stability of PuO2 NP in the acidic and alkaline pH regime. PuO2 NP aggregation and precipitation as function electrolyte concentration is tracked by a combination of liquid scintillation counting, dynamic light scattering for determination of particle size distributions, and zeta potentials as a proxy for particle charge. At acidic pH, electrolytes containing non-coordinating anions, such as NaNO3, NaCl, and NaClO4 mostly stabilize PuO2 NPs over a large electrolyte concentration range, showing only subtle differences in their reactivity. Other electrolyte anions show a more pronounced effect on the PuO2 NP stability: SO42-, binds directly to the particles’ surface, reverses the particle charge, and precipitates the PuO2 NPs efficiently even at intermediate sulfate concentrations (>0.1 M). In contrast, C2O42- is found to lead to high [Pu] in solution, in the milli-molar range, even at mildly acidic pH (~4). Thermodynamic modeling of the dissolved Pu concentrations using PHREEQC is unable to predict the observed [Pu] in the acidic pH regime, supporting the influence of colloids in maintaining elevated [Pu]. It is noteworthy that the current thermodynamic databases do not include constants for colloidal Pu phases and cannot accurately predict many of the high ionic strength solutions relevant to this work. The mechanisms and models responsible for these observations will need further investigation in the future. At high pH values (~12), PuO2 NPs exhibits classical sol-gel chemistry, meaning that upon destabilization of the colloidal sol, for example by addition of concentrated NaOH, highly porous and viscid PuO2 coagulates are formed that consist of a three-dimensional network likely held together by physical interactions. The PuO2 NP coagulate shows no significant reversibility of the aggregation when contacted with concentrated brines; however, PuO2 NPs can be efficiently resuspended in solution by addition of diluted electrolytes, alkaline solutions containing high amounts of carbonate, or simple addition of water. Especially carbonate is shown to stabilize PuO2 NPs in solution at high pH, characterized by stable colloidal suspensions that are resistant against sedimentation during centrifugation. Thermodynamic modeling of the carbonate system was able to predict an increasing dissolved Pu concentration with increasing carbonate concentration. However, the model was profoundly sensitive to the fixed redox potential and does not include any thermodynamic constants for colloidal Pu species.

Neumann, Julia↗
DOE OSTI2021

Commonly Overlooked Material Attractiveness Issues [Slides]

SG-Pu, WG-Pu, FG-Pu, RG-Pu, HEU, and Np should not be ignored in safeguards or security discussions: Nation states prefer SG-Pu and WG-Pu for missile delivery. Terrorists and some nation states will prefer FG-Pu and RG-Pu to minimize the mass that must be stolen/diverted and to minimize the risk of detection. Terrorists and some nation states will prefer HEU to eliminate the need for testing. A nation state with reprocessing capabilities might prefer 237 Np because the IAEA doesn’t require it to be safeguarded. Terrorists might prefer 237 Np if the nation state does not provide adequate safeguards and security for it.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuB2Rh3 by Materials Project

PuRh3B2 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Pu is bonded in a 12-coordinate geometry to two equivalent Pu, twelve equivalent Rh, and six equivalent B atoms. Both Pu–Pu bond lengths are 2.93 Å. All Pu–Rh bond lengths are 3.18 Å. All Pu–B bond lengths are 3.26 Å. Rh is bonded in a distorted square co-planar geometry to four equivalent Pu and four equivalent B atoms. All Rh–B bond lengths are 2.19 Å. B is bonded in a 6-coordinate geometry to three equivalent Pu and six equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuB7IO14 by Materials Project

Pu(BO2)7I crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four hydriodic acid molecules and one Pu(BO2)7 framework. In the Pu(BO2)7 framework, Pu is bonded in a 3-coordinate geometry to three O atoms. There are a spread of Pu–O bond distances ranging from 1.82–2.05 Å. There are seven inequivalent B sites. In the first B site, B is bonded in a trigonal planar geometry to three O atoms. All B–O bond lengths are 1.37 Å. In the second B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.43–1.55 Å. In the third B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.44–1.49 Å. In the fourth B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.43–1.51 Å. In the fifth B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.36–1.39 Å. In the sixth B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.34–1.41 Å. In the seventh B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.35–1.40 Å. There are fourteen inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the second O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the third O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the fourth O site, O is bonded in a trigonal planar geometry to three B atoms. In the fifth O site, O is bonded in a distorted bent 120 degrees geometry to two B atoms. In the sixth O site, O is bonded in a bent 150 degrees geometry to two B atoms. In the seventh O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the eighth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the ninth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the tenth O site, O is bonded in a bent 150 degrees geometry to one Pu and one B atom. In the eleventh O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the twelfth O site, O is bonded in a single-bond geometry to one Pu atom. In the thirteenth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the fourteenth O site, O is bonded in a single-bond geometry to one Pu atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu3Si2 by Materials Project

Pu3Si2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Pu sites. In the first Pu site, Pu is bonded in a square co-planar geometry to four equivalent Si atoms. All Pu–Si bond lengths are 2.90 Å. In the second Pu site, Pu is bonded in a 6-coordinate geometry to six equivalent Si atoms. There are two shorter (2.90 Å) and four longer (3.00 Å) Pu–Si bond lengths. Si is bonded in a 9-coordinate geometry to eight Pu and one Si atom. The Si–Si bond length is 2.38 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce4Pu by Materials Project

PuCe4 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pu is bonded to six equivalent Pu and six equivalent Ce atoms to form PuCe6Pu6 cuboctahedra that share corners with six equivalent PuCe6Pu6 cuboctahedra, corners with six CeCe12 cuboctahedra, edges with six equivalent PuCe6Pu6 cuboctahedra, edges with eighteen CeCe9Pu3 cuboctahedra, faces with six equivalent PuCe6Pu6 cuboctahedra, and faces with twelve equivalent CeCe9Pu3 cuboctahedra. All Pu–Pu bond lengths are 3.21 Å. All Pu–Ce bond lengths are 3.14 Å. There are eight inequivalent Ce sites. In the first Ce site, Ce is bonded to three equivalent Pu and nine Ce atoms to form CeCe9Pu3 cuboctahedra that share corners with twelve CeCe9Pu3 cuboctahedra, edges with six equivalent PuCe6Pu6 cuboctahedra, edges with eighteen CeCe9Pu3 cuboctahedra, faces with six equivalent PuCe6Pu6 cuboctahedra, and faces with twelve CeCe9Pu3 cuboctahedra. There are six shorter (3.21 Å) and three longer (3.30 Å) Ce–Ce bond lengths. In the second Ce site, Ce is bonded to twelve Ce atoms to form CeCe12 cuboctahedra that share corners with three equivalent PuCe6Pu6 cuboctahedra, corners with nine CeCe9Pu3 cuboctahedra, edges with three equivalent PuCe6Pu6 cuboctahedra, edges with twenty-one CeCe9Pu3 cuboctahedra, and faces with eighteen CeCe9Pu3 cuboctahedra. There are six shorter (3.21 Å) and three longer (3.29 Å) Ce–Ce bond lengths. In the third Ce site, Ce is bonded to twelve Ce atoms to form CeCe12 cuboctahedra that share corners with three equivalent PuCe6Pu6 cuboctahedra, corners with nine CeCe9Pu3 cuboctahedra, edges with three equivalent PuCe6Pu6 cuboctahedra, edges with twenty-one CeCe9Pu3 cuboctahedra, and faces with eighteen CeCe9Pu3 cuboctahedra. There are six shorter (3.21 Å) and three longer (3.30 Å) Ce–Ce bond lengths. In the fourth Ce site, Ce is bonded to twelve Ce atoms to form CeCe12 cuboctahedra that share corners with three equivalent PuCe6Pu6 cuboctahedra, corners with nine CeCe9Pu3 cuboctahedra, edges with three equivalent PuCe6Pu6 cuboctahedra, edges with twenty-one CeCe9Pu3 cuboctahedra, and faces with eighteen CeCe9Pu3 cuboctahedra. There are a spread of Ce–Ce bond distances ranging from 3.21–3.30 Å. In the fifth Ce site, Ce is bonded to twelve Ce atoms to form CeCe12 cuboctahedra that share corners with three equivalent PuCe6Pu6 cuboctahedra, corners with nine CeCe9Pu3 cuboctahedra, edges with three equivalent PuCe6Pu6 cuboctahedra, edges with twenty-one CeCe9Pu3 cuboctahedra, and faces with eighteen CeCe9Pu3 cuboctahedra. There are six shorter (3.21 Å) and three longer (3.30 Å) Ce–Ce bond lengths. In the sixth Ce site, Ce is bonded to twelve Ce atoms to form CeCe12 cuboctahedra that share corners with three equivalent PuCe6Pu6 cuboctahedra, corners with fourteen CeCe12 cuboctahedra, edges with three equivalent PuCe6Pu6 cuboctahedra, edges with nineteen CeCe9Pu3 cuboctahedra, and faces with twenty-one CeCe9Pu3 cuboctahedra. There are a spread of Ce–Ce bond distances ranging from 3.21–3.30 Å. In the seventh Ce site, Ce is bonded to sixteen Ce atoms to form CeCe16 cuboctahedra that share corners with three equivalent PuCe6Pu6 cuboctahedra, corners with nineteen CeCe9Pu3 cuboctahedra, edges with three equivalent PuCe6Pu6 cuboctahedra, edges with twenty-one CeCe9Pu3 cuboctahedra, and faces with thirty-four CeCe12 cuboctahedra. There are a spread of Ce–Ce bond distances ranging from 3.21–6.42 Å. In the eighth Ce site, Ce is bonded to three equivalent Pu and nine Ce atoms to form CeCe9Pu3 cuboctahedra that share corners with seventeen CeCe9Pu3 cuboctahedra, edges with six equivalent PuCe6Pu6 cuboctahedra, edges with sixteen CeCe9Pu3 cuboctahedra, faces with six equivalent PuCe6Pu6 cuboctahedra, and faces with fifteen CeCe16 cuboctahedra. All Ce–Pu bond lengths are 3.14 Å. All Ce–Ce bond lengths are 3.21 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu3I by Materials Project

Pu3I is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Pu sites. In the first Pu site, Pu is bonded to four equivalent I atoms to form a mixture of distorted edge and corner-sharing PuI4 cuboctahedra. All Pu–I bond lengths are 3.28 Å. In the second Pu site, Pu is bonded in a square co-planar geometry to four equivalent I atoms. All Pu–I bond lengths are 3.17 Å. I is bonded to twelve Pu atoms to form a mixture of edge, corner, and face-sharing IPu12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuB2Ir3 by Materials Project

PuIr3B2 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Pu is bonded in a 12-coordinate geometry to two equivalent Pu, twelve equivalent Ir, and six equivalent B atoms. Both Pu–Pu bond lengths are 3.12 Å. All Pu–Ir bond lengths are 3.15 Å. All Pu–B bond lengths are 3.16 Å. Ir is bonded in a distorted square co-planar geometry to four equivalent Pu and four equivalent B atoms. All Ir–B bond lengths are 2.22 Å. B is bonded in a 6-coordinate geometry to three equivalent Pu and six equivalent Ir atoms.

36 MATERIALS SCIENCE↗