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At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Characterization of CST Post-Processing AP-105 Hanford Tank Waste

The primary goal of the Tank Side Cesium Removal (TSCR) system, under development by Washington River Protection Solutions, LLC (WRPS), is to remove entrained solids and 137 Cs from the Hanford tank waste supernate to expedite production of low-activity waste. Ion exchange (IX) testing of 10.9 L of waste from Hanford tank 241-AP-105 (AP-105), performed by Pacific Northwest National Laboratory, used a lead-lag-polish column format, with a bed volume of 10 mL per column, to decontaminate tank waste supernate using crystalline silicotitanate (CST) as the IX media. The AP-105 Cs IX processing test, discussed elsewhere, resulted in a shorter transition zone (i.e., steeper load curve) than those defined by wastes from tanks 241-AP-107 and 241-AW-102.1 The shorter transition zone was indicative of a matrix effect retarding Cs capacity. Therefore, aliquots of spent CST from the lead, lag, and polish columns were subjected to a digestion protocol to quantify analytes retained by the CST and extrapolate the impact on Cs capacity. The spent CST was digested using a combination of 5 M HNO 3 and H 2 O 2 with vigorous heating and stirring. Due to the radiation dose accompanying the 137 Cs on the CST columns, a secondary Cs separation by ammonium molybdophosphate embedded in polyacrylonitrile (AMP-PAN) was performed to separate the 137 Cs from the CST so the samples could be contact-handled for analysis outside of a shielded facility.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Materials Data on Cs3P7 by Materials Project

Cs3P7 crystallizes in the tetragonal P4_1 space group. The structure is three-dimensional. there are three inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 1-coordinate geometry to ten P+0.43- atoms. There are a spread of Cs–P bond distances ranging from 3.66–4.05 Å. In the second Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to nine P+0.43- atoms. There are a spread of Cs–P bond distances ranging from 3.69–4.20 Å. In the third Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight P+0.43- atoms. There are a spread of Cs–P bond distances ranging from 3.64–3.94 Å. There are seven inequivalent P+0.43- sites. In the first P+0.43- site, P+0.43- is bonded in a 7-coordinate geometry to four Cs1+ and three P+0.43- atoms. There are a spread of P–P bond distances ranging from 2.14–2.31 Å. In the second P+0.43- site, P+0.43- is bonded in a 6-coordinate geometry to three Cs1+ and three P+0.43- atoms. There are one shorter (2.14 Å) and one longer (2.31 Å) P–P bond lengths. In the third P+0.43- site, P+0.43- is bonded to four Cs1+ and two P+0.43- atoms to form distorted PCs4P2 pentagonal pyramids that share corners with two equivalent PCs3P3 octahedra, corners with two equivalent PCs4P2 pentagonal pyramids, and an edgeedge with one PCs3P3 octahedra. The corner-sharing octahedra tilt angles range from 37–145°. There are one shorter (2.14 Å) and one longer (2.20 Å) P–P bond lengths. In the fourth P+0.43- site, P+0.43- is bonded in a 6-coordinate geometry to four Cs1+ and two P+0.43- atoms. The P–P bond length is 2.19 Å. In the fifth P+0.43- site, P+0.43- is bonded in a 7-coordinate geometry to five Cs1+ and two P+0.43- atoms. The P–P bond length is 2.20 Å. In the sixth P+0.43- site, P+0.43- is bonded to three Cs1+ and three P+0.43- atoms to form distorted PCs3P3 octahedra that share corners with two equivalent PCs3P3 octahedra, corners with two equivalent PCs4P2 pentagonal pyramids, and an edgeedge with one PCs4P2 pentagonal pyramid. The corner-sharing octahedral tilt angles are 61°. In the seventh P+0.43- site, P+0.43- is bonded in a 7-coordinate geometry to four Cs1+ and three P+0.43- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs7(InAs2)3 by Materials Project

Cs7(InAs2)3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are seven inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 3-coordinate geometry to four As+2.67- atoms. There are a spread of Cs–As bond distances ranging from 3.67–4.17 Å. In the second Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six As+2.67- atoms. There are a spread of Cs–As bond distances ranging from 3.51–3.91 Å. In the third Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to six As+2.67- atoms. There are a spread of Cs–As bond distances ranging from 3.64–4.09 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four As+2.67- atoms. There are a spread of Cs–As bond distances ranging from 3.56–4.11 Å. In the fifth Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to five As+2.67- atoms. There are a spread of Cs–As bond distances ranging from 3.67–4.05 Å. In the sixth Cs1+ site, Cs1+ is bonded in a 3-coordinate geometry to three As+2.67- atoms. There are a spread of Cs–As bond distances ranging from 3.72–3.94 Å. In the seventh Cs1+ site, Cs1+ is bonded in a 3-coordinate geometry to three As+2.67- atoms. There are a spread of Cs–As bond distances ranging from 3.66–4.22 Å. There are three inequivalent In3+ sites. In the first In3+ site, In3+ is bonded in a distorted T-shaped geometry to three As+2.67- atoms. There are a spread of In–As bond distances ranging from 2.89–2.94 Å. In the second In3+ site, In3+ is bonded in a distorted T-shaped geometry to three As+2.67- atoms. There are a spread of In–As bond distances ranging from 2.87–2.97 Å. In the third In3+ site, In3+ is bonded in a distorted T-shaped geometry to three As+2.67- atoms. There are a spread of In–As bond distances ranging from 2.90–2.96 Å. There are six inequivalent As+2.67- sites. In the first As+2.67- site, As+2.67- is bonded in a 7-coordinate geometry to three Cs1+ and four As+2.67- atoms. There are a spread of As–As bond distances ranging from 2.38–2.56 Å. In the second As+2.67- site, As+2.67- is bonded in a 8-coordinate geometry to seven Cs1+ and one As+2.67- atom. In the third As+2.67- site, As+2.67- is bonded in a 9-coordinate geometry to six Cs1+, two In3+, and one As+2.67- atom. In the fourth As+2.67- site, As+2.67- is bonded in a 7-coordinate geometry to four Cs1+, two In3+, and one As+2.67- atom. In the fifth As+2.67- site, As+2.67- is bonded in a 7-coordinate geometry to five Cs1+, two In3+, and one As+2.67- atom. In the sixth As+2.67- site, As+2.67- is bonded in a 9-coordinate geometry to six Cs1+ and three In3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsU(PO4)2 by Materials Project

CsU(PO4)2 crystallizes in the monoclinic P2_1/m space group. The structure is two-dimensional and consists of one CsU(PO4)2 sheet oriented in the (1, 0, 0) direction. Cs1+ is bonded in a 1-coordinate geometry to one O2- atom. The Cs–O bond length is 2.95 Å. U5+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of U–O bond distances ranging from 2.15–2.47 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.54 Å) and two longer (1.57 Å) P–O bond length. In the second P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.49–1.58 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one U5+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one U5+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Cs1+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one U5+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to one U5+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U5+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3V(Cl3O2)2 by Materials Project

Cs3V(O2Cl3)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in a body-centered cubic geometry to eight Cl atoms. There are four shorter (3.41 Å) and four longer (3.43 Å) Cs–Cl bond lengths. In the second Cs site, Cs is bonded in a distorted body-centered cubic geometry to eight Cl atoms. There are a spread of Cs–Cl bond distances ranging from 3.46–3.78 Å. V is bonded in an octahedral geometry to four equivalent O and two equivalent Cl atoms. All V–O bond lengths are 1.83 Å. Both V–Cl bond lengths are 2.40 Å. O is bonded in a single-bond geometry to one V atom. There are two inequivalent Cl sites. In the first Cl site, Cl is bonded in a see-saw-like geometry to four Cs atoms. In the second Cl site, Cl is bonded in a 1-coordinate geometry to four Cs and one V atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3P11(H3N)3 by Materials Project

Cs3P11(NH3)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to four P+0.09-, one N3-, and one H+0.78+ atom. There are a spread of Cs–P bond distances ranging from 3.75–4.06 Å. The Cs–N bond length is 3.09 Å. The Cs–H bond length is 3.31 Å. In the second Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to eight P+0.09- and one N3- atom. There are a spread of Cs–P bond distances ranging from 3.74–4.06 Å. The Cs–N bond length is 3.55 Å. In the third Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to seven P+0.09-, one N3-, and three H+0.78+ atoms. There are a spread of Cs–P bond distances ranging from 3.66–4.09 Å. The Cs–N bond length is 3.14 Å. There are a spread of Cs–H bond distances ranging from 3.02–3.45 Å. There are eleven inequivalent P+0.09- sites. In the first P+0.09- site, P+0.09- is bonded in a 6-coordinate geometry to three Cs1+ and three P+0.09- atoms. There are a spread of P–P bond distances ranging from 2.17–2.26 Å. In the second P+0.09- site, P+0.09- is bonded in a 5-coordinate geometry to two Cs1+ and three P+0.09- atoms. There are a spread of P–P bond distances ranging from 2.17–2.26 Å. In the third P+0.09- site, P+0.09- is bonded to three Cs1+ and two P+0.09- atoms to form a mixture of distorted edge and corner-sharing PCs3P2 square pyramids. There are one shorter (2.17 Å) and one longer (2.18 Å) P–P bond lengths. In the fourth P+0.09- site, P+0.09- is bonded to two equivalent Cs1+ and three P+0.09- atoms to form distorted PCs2P3 trigonal bipyramids that share a cornercorner with one PCs3P2 square pyramid, an edgeedge with one PCs3P2 square pyramid, and an edgeedge with one PCs2P3 trigonal bipyramid. There are a spread of P–P bond distances ranging from 2.17–2.27 Å. In the fifth P+0.09- site, P+0.09- is bonded in a 3-coordinate geometry to one Cs1+ and three P+0.09- atoms. There are one shorter (2.18 Å) and one longer (2.27 Å) P–P bond lengths. In the sixth P+0.09- site, P+0.09- is bonded in a 2-coordinate geometry to two Cs1+ and two P+0.09- atoms. In the seventh P+0.09- site, P+0.09- is bonded in a 3-coordinate geometry to one Cs1+ and three P+0.09- atoms. The P–P bond length is 2.28 Å. In the eighth P+0.09- site, P+0.09- is bonded in a distorted trigonal non-coplanar geometry to three P+0.09- atoms. In the ninth P+0.09- site, P+0.09- is bonded in a 4-coordinate geometry to one Cs1+ and three P+0.09- atoms. The P–P bond length is 2.27 Å. In the tenth P+0.09- site, P+0.09- is bonded in a 4-coordinate geometry to three Cs1+ and two P+0.09- atoms. In the eleventh P+0.09- site, P+0.09- is bonded in a 4-coordinate geometry to one Cs1+ and three P+0.09- atoms. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a trigonal non-coplanar geometry to one Cs1+ and three H+0.78+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. In the second N3- site, N3- is bonded in a trigonal non-coplanar geometry to one Cs1+ and three H+0.78+ atoms. There is two shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the third N3- site, N3- is bonded in a trigonal non-coplanar geometry to one Cs1+ and three H+0.78+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. There are nine inequivalent H+0.78+ sites. In the first H+0.78+ site, H+0.78+ is bonded in a single-bond geometry to one N3- atom. In the second H+0.78+ site, H+0.78+ is bonded in a single-bond geometry to one Cs1+ and one N3- atom. In the third H+0.78+ site, H+0.78+ is bonded in a single-bond geometry to two Cs1+ and one N3- atom. In the fourth H+0.78+ site, H+0.78+ is bonded in a single-bond geometry to one N3- atom. In the fifth H+0.78+ site, H+0.78+ is bonded in a single-bond geometry to one N3- atom. In the sixth H+0.78+ site, H+0.78+ is bonded in a single-bond geometry to one N3- atom. In the seventh H+0.78+ site, H+0.78+ is bonded in a single-bond geometry to one Cs1+ and one N3- atom. In the eighth H+0.78+ site, H+0.78+ is bonded in a single-bond geometry to one N3- atom. In the ninth H+0.78+ site, H+0.78+ is bonded in a single-bond geometry to one N3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Uptake and binding of La 3+ and Cr 3+ ions by alkali metal substituted alpha-zirconium phosphate

The conversion of alpha-zirconium phosphate, Zr(HPO 4 ) 2 ·H 2 O, to the K-, Rb-, and Cs-phases and the subsequent ion exchange behavior of these alkali metal phases, A-ZrP, with La 3+ and Cr 3+ have been investigated. The conversion to the A-ZrP phases was achieved by reaction with metal chloride, metal hydroxide solution, and confirmed through various techniques, including X-ray powder diffraction, thermogravimetry analysis, IR spectroscopy, scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy. The effect of material hydration, which increased the interlayer distance, was also examined. The ion exchange behavior of the A-ZrP showed strong affinity for both La 3+ , a representative for trivalent lanthanide metals, and Cr 3+ , a representative for the trivalent transition metals, with a rapid, near quantitative removal of the M 3+ ions at a pH of 3 when the ion concentration was ≤25% of the ion exchange capacity of the materials. Additionally, the ion affinity was shown to be pH and concentration-dependent, decreasing with a decrease in pH or an increase in ion concentration. Lastly, the binding strength of La- and Cr-loaded ZrP materials was examined through a series of leaching experiments in a carbonate buffer, phosphate buffer, HEPES buffer, and a series of EDTA solutions at various concentrations. No observable leaching occurred in the carbonate buffer, phosphate buffer, HEPES buffer, or when the EDTA concentration was below 0.1 mM. These results highlight the potential for the A-ZrP materials to provide a platform for trivalent transition metal and trivalent lanthanide radionuclide capture for various applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Hydration and transport properties of cesium hydroxide and mixed cesium hydroxide–sodium nitrite aqueous solutions

Here, this study explores the hydration and transport properties of aqueous cesium hydroxide (CsOH) solution, with or without 1 molar (M) sodium nitrite (NaNO 2 ). Historic studies of electrolyte solutions indicate that Cs + ions decrease viscosity and increase diffusion rates, whereas OH − ions have the opposite effect. Here, the influence of OH − was dominant in CsOH solutions, leading to increased viscosity and reduced diffusion rates. There was a linear relationship between diffusion coefficients and water activity, emphasizing the significant role of ion–water interactions in determining transport properties. This may be because the interaction between Cs + and the anions is weak even when they are in direct contact with each other. The weakness of the ion-pairing was established through thermodynamic analysis. The findings suggest that ion-pairing is not the only important interaction controlling transport properties when ion-pairing is weak. Nonetheless, ion-pairing or obstructions did result in more sluggish transport properties as electrolyte concentrations increased. Overall, the research enhances the understanding of the complexities underlying ion interactions in multicomponent solutions.

Reynolds, Jacob G. [Hanford Site (HNF), Richland, ↗
NASA NTRS2016

Flight Test 4 Preliminary Results: NASA Ames SSI

Realization of the expected proliferation of Unmanned Aircraft System (UAS) operations in the National Airspace System (NAS) depends on the development and validation of performance standards for UAS Detect and Avoid (DAA) Systems. The RTCA Special Committee 228 is charged with leading the development of draft Minimum Operational Performance Standards (MOPS) for UAS DAA Systems. NASA, as a participating member of RTCA SC-228 is committed to supporting the development and validation of draft requirements as well as the safety substantiation and end-to-end assessment of DAA system performance. The Unmanned Aircraft System (UAS) Integration into the National Airspace System (NAS) Project conducted flight test program, referred to as Flight Test 4, at Armstrong Flight Research Center from April -June 2016. Part of the test flights were dedicated to the NASA Ames-developed Detect and Avoid (DAA) System referred to as JADEM (Java Architecture for DAA Extensibility and Modeling). The encounter scenarios, which involved NASA's Ikhana UAS and a manned intruder aircraft, were designed to collect data on DAA system performance in real-world conditions and uncertainties with four different surveillance sensor systems. Flight test 4 has four objectives: (1) validate DAA requirements in stressing cases that drive MOPS requirements, including: high-speed cooperative intruder, low-speed non-cooperative intruder, high vertical closure rate encounter, and Mode CS-only intruder (i.e. without ADS-B), (2) validate TCASDAA alerting and guidance interoperability concept in the presence of realistic sensor, tracking and navigational errors and in multiple-intruder encounters against both cooperative and non-cooperative intruders, (3) validate Well Clear Recovery guidance in the presence of realistic sensor, tracking and navigational errors, and (4) validate DAA alerting and guidance requirements in the presence of realistic sensor, tracking and navigational errors. The results will be presented at RTCA Special Committee 228 in support of final verification and validation of the DAA MOPS.

Detect-And-Avoid (DAA)↗
DOE OSTI2020

Materials Data on CsInH2(SeO4)2 by Materials Project

CsIn(SeO4)2H2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional and consists of four hydrogen molecules and one CsIn(SeO4)2 framework. In the CsIn(SeO4)2 framework, Cs1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Cs–O bond distances ranging from 3.15–3.65 Å. In3+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are two shorter (2.08 Å) and two longer (2.10 Å) In–O bond lengths. Se5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Se–O bond distances ranging from 1.63–1.74 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Cs1+, one In3+, and one Se5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one In3+ and one Se5+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Cs1+ and one Se5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Cs1+ and one Se5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs13Nb2(In3As5)2 by Materials Project

Cs13Nb2(In3As5)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are thirteen inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to five As3- atoms. There are a spread of Cs–As bond distances ranging from 3.63–4.19 Å. In the second Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to five As3- atoms. There are a spread of Cs–As bond distances ranging from 3.63–4.19 Å. In the third Cs1+ site, Cs1+ is bonded in a 1-coordinate geometry to one Cs1+ and two As3- atoms. The Cs–Cs bond length is 4.00 Å. There are one shorter (3.52 Å) and one longer (3.88 Å) Cs–As bond lengths. In the fourth Cs1+ site, Cs1+ is bonded in a 1-coordinate geometry to one Cs1+ and three As3- atoms. The Cs–Cs bond length is 4.00 Å. There are a spread of Cs–As bond distances ranging from 3.52–4.36 Å. In the fifth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four As3- atoms. There are a spread of Cs–As bond distances ranging from 3.92–4.03 Å. In the sixth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four As3- atoms. There are a spread of Cs–As bond distances ranging from 3.92–4.03 Å. In the seventh Cs1+ site, Cs1+ is bonded in a 3-coordinate geometry to five As3- atoms. There are a spread of Cs–As bond distances ranging from 3.75–4.09 Å. In the eighth Cs1+ site, Cs1+ is bonded in a 3-coordinate geometry to five As3- atoms. There are a spread of Cs–As bond distances ranging from 3.75–4.09 Å. In the ninth Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to four Cs1+ and six As3- atoms. Both Cs–Cs bond lengths are 4.09 Å. There are a spread of Cs–As bond distances ranging from 3.60–4.07 Å. In the tenth Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to one Cs1+ and three As3- atoms. There are a spread of Cs–As bond distances ranging from 3.65–4.14 Å. In the eleventh Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to one Cs1+ and three As3- atoms. There are a spread of Cs–As bond distances ranging from 3.65–4.15 Å. In the twelfth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four As3- atoms. There are a spread of Cs–As bond distances ranging from 3.69–4.16 Å. In the thirteenth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four As3- atoms. There are a spread of Cs–As bond distances ranging from 3.70–4.16 Å. There are two inequivalent Nb+3.50+ sites. In the first Nb+3.50+ site, Nb+3.50+ is bonded in a tetrahedral geometry to four As3- atoms. There are a spread of Nb–As bond distances ranging from 2.43–2.60 Å. In the second Nb+3.50+ site, Nb+3.50+ is bonded in a tetrahedral geometry to four As3- atoms. There are a spread of Nb–As bond distances ranging from 2.43–2.60 Å. There are six inequivalent In+1.67+ sites. In the first In+1.67+ site, In+1.67+ is bonded in a distorted T-shaped geometry to three As3- atoms. There are a spread of In–As bond distances ranging from 2.87–2.99 Å. In the second In+1.67+ site, In+1.67+ is bonded in a distorted T-shaped geometry to three As3- atoms. There are a spread of In–As bond distances ranging from 2.87–2.99 Å. In the third In+1.67+ site, In+1.67+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are a spread of In–As bond distances ranging from 2.81–2.84 Å. In the fourth In+1.67+ site, In+1.67+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are a spread of In–As bond distances ranging from 2.81–2.84 Å. In the fifth In+1.67+ site, In+1.67+ is bonded in a distorted T-shaped geometry to three As3- atoms. There are a spread of In–As bond distances ranging from 2.90–2.92 Å. In the sixth In+1.67+ site, In+1.67+ is bonded in a distorted T-shaped geometry to three As3- atoms. There are a spread of In–As bond distances ranging from 2.90–2.92 Å. There are ten inequivalent As3- sites. In the first As3- site, As3- is bonded in a 1-coordinate geometry to six Cs1+, one Nb+3.50+, and two In+1.67+ atoms. In the second As3- site, As3- is bonded in a 1-coordinate geometry to five Cs1+, one Nb+3.50+, and two In+1.67+ atoms. In the third As3- site, As3- is bonded in a 1-coordinate geometry to two Cs1+, one Nb+3.50+, and two In+1.67+ atoms. In the fourth As3- site, As3- is bonded in a 1-coordinate geometry to two Cs1+, one Nb+3.50+, and two In+1.67+ atoms. In the fifth As3- site, As3- is bonded in a 1-coordinate geometry to six Cs1+, one Nb+3.50+, and two In+1.67+ atoms. In the sixth As3- site, As3- is bonded in a 1-coordinate geometry to six Cs1+, one Nb+3.50+, and two In+1.67+ atoms. In the seventh As3- site, As3- is bonded in a 9-coordinate geometry to six Cs1+ and three In+1.67+ atoms. In the eighth As3- site, As3- is bonded in a 9-coordinate geometry to six Cs1+ and three In+1.67+ atoms. In the ninth As3- site, As3- is bonded in a 1-coordinate geometry to seven Cs1+ and one Nb+3.50+ atom. In the tenth As3- site, As3- is bonded in a 1-coordinate geometry to seven Cs1+ and one Nb+3.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Solvent and Temperature Effects on Photoinduced Proton-Coupled Electron Transfer in the Marcus Inverted Region

Concerted proton-coupled electron transfer (PCET) in the Marcus inverted region was recently demonstrated. Understanding the requirements for such reactivity is fundamentally important and holds promise as a design principle for solar energy conversion systems. Herein, we investigate the solvent polarity and temperature dependence of photoinduced proton-coupled charge separation (CS) and charge recombination (CR) in anthracene–phenol–pyridine triads: 1 (10-(4-hydroxy-3-(4-methylpyridin-2-yl)benzyl)anthracene-9-carbonitrile) and 2 (10-(4-hydroxy-3-(4-methoxypyridin-2-yl)benzyl)anthracene-9-carbonitrile). Both the CS and CR rate constants increased with increasing polarity in acetonitrile:n-butyronitrile mixtures. The kinetics were semi-quantitatively analyzed where changes in dielectric and refractive index, and thus consequently changes in driving force (–ΔG°) and reorganization energy (λ), were accounted for. The results were further validated by fitting the temperature dependence, from 180 to 298 K, in n-butyronitrile. The analyses support previous computational work where transitions to proton vibrational excited states dominate the CR reaction with a distinct activation free energy (ΔG* CR ~ 140 meV). However, the solvent continuum model fails to accurately describe the changes in ΔG° and λ with temperature via changes in dielectric constant and refractive index. Satisfactory modeling was obtained using the results of a molecular solvent model, which predicts that λ decreases with temperature, opposite to that of the continuum model. To further assess the solvent polarity control in the inverted region, the reactions were studied in toluene. Nonpolar solvents decrease both ΔG° CR and λ, slowing CR into the nanosecond time regime for 2 in toluene at 298 K. This demonstrates how PCET in the inverted region may be controlled to potentially use proton-coupled CS states for efficient solar fuel production and photoredox catalysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Cs2VH2(OF2)2 by Materials Project

Cs2VH2(OF2)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 12-coordinate geometry to two equivalent H1+, four equivalent O2-, and eight F1- atoms. Both Cs–H bond lengths are 3.33 Å. There are two shorter (3.28 Å) and two longer (3.53 Å) Cs–O bond lengths. There are a spread of Cs–F bond distances ranging from 3.18–3.52 Å. In the second Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to two equivalent F1- atoms. Both Cs–F bond lengths are 2.93 Å. V4+ is bonded in a distorted octahedral geometry to two O2- and four F1- atoms. There is one shorter (1.67 Å) and one longer (2.31 Å) V–O bond length. There is two shorter (1.95 Å) and two longer (1.98 Å) V–F bond length. H1+ is bonded in a single-bond geometry to one Cs1+ and one O2- atom. The H–O bond length is 0.99 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to four equivalent Cs1+ and one V4+ atom. In the second O2- site, O2- is bonded in a distorted water-like geometry to one V4+ and two equivalent H1+ atoms. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to three Cs1+ and one V4+ atom. In the second F1- site, F1- is bonded in a distorted single-bond geometry to two equivalent Cs1+ and one V4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsReS2 by Materials Project

CsReS2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Cs–S bond distances ranging from 3.34–3.70 Å. In the second Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to two S2- atoms. There are one shorter (3.29 Å) and one longer (3.33 Å) Cs–S bond lengths. In the third Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Cs–S bond distances ranging from 3.36–3.87 Å. There are five inequivalent Re3+ sites. In the first Re3+ site, Re3+ is bonded to five S2- atoms to form a mixture of corner and edge-sharing ReS5 square pyramids. There are four shorter (2.43 Å) and one longer (2.48 Å) Re–S bond lengths. In the second Re3+ site, Re3+ is bonded to five S2- atoms to form a mixture of corner and edge-sharing ReS5 square pyramids. There are a spread of Re–S bond distances ranging from 2.42–2.50 Å. In the third Re3+ site, Re3+ is bonded to five S2- atoms to form edge-sharing ReS5 square pyramids. There are a spread of Re–S bond distances ranging from 2.41–2.46 Å. In the fourth Re3+ site, Re3+ is bonded to five S2- atoms to form a mixture of corner and edge-sharing ReS5 square pyramids. There are four shorter (2.43 Å) and one longer (2.47 Å) Re–S bond lengths. In the fifth Re3+ site, Re3+ is bonded to five S2- atoms to form a mixture of corner and edge-sharing ReS5 square pyramids. There are a spread of Re–S bond distances ranging from 2.43–2.48 Å. There are seven inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two Cs1+ and three Re3+ atoms. In the second S2- site, S2- is bonded in a 6-coordinate geometry to three Cs1+ and three Re3+ atoms. In the third S2- site, S2- is bonded in a 2-coordinate geometry to two equivalent Cs1+ and two Re3+ atoms. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to three Cs1+ and three Re3+ atoms. In the fifth S2- site, S2- is bonded in a 1-coordinate geometry to one Cs1+ and one Re3+ atom. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to two Cs1+ and three Re3+ atoms. In the seventh S2- site, S2- is bonded in a 2-coordinate geometry to four Cs1+ and two Re3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2W(OF2)2 by Materials Project

Cs2WO2F4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Cs1+ is bonded in a 12-coordinate geometry to four equivalent O2- and eight equivalent F1- atoms. There are a spread of Cs–O bond distances ranging from 3.21–3.45 Å. There are a spread of Cs–F bond distances ranging from 3.24–3.40 Å. W6+ is bonded in an octahedral geometry to two equivalent O2- and four equivalent F1- atoms. Both W–O bond lengths are 1.84 Å. All W–F bond lengths are 1.98 Å. O2- is bonded in a distorted single-bond geometry to four equivalent Cs1+ and one W6+ atom. F1- is bonded in a distorted single-bond geometry to four equivalent Cs1+ and one W6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3SrCu2C7(SN)7 by Materials Project

Cs3SrCu2C7(NS)7 crystallizes in the tetragonal I-42m space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to two equivalent N3- atoms. Both Cs–N bond lengths are 3.17 Å. In the second Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.75 Å) and four longer (4.03 Å) Cs–S bond lengths. Sr2+ is bonded in a 9-coordinate geometry to nine N3- atoms. There are a spread of Sr–N bond distances ranging from 2.74–2.86 Å. Cu1+ is bonded to four S2- atoms to form corner-sharing CuS4 tetrahedra. There are a spread of Cu–S bond distances ranging from 2.32–2.37 Å. There are three inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a distorted linear geometry to one N3- and one S2- atom. The C–N bond length is 1.19 Å. The C–S bond length is 1.64 Å. In the second C4+ site, C4+ is bonded in a linear geometry to one N3- and one S2- atom. The C–N bond length is 1.18 Å. The C–S bond length is 1.66 Å. In the third C4+ site, C4+ is bonded in a distorted linear geometry to one N3- and one S2- atom. The C–N bond length is 1.18 Å. The C–S bond length is 1.65 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one C4+ atom. In the second N3- site, N3- is bonded in a distorted linear geometry to one Sr2+ and one C4+ atom. In the third N3- site, N3- is bonded in a 1-coordinate geometry to one Cs1+, one Sr2+, and one C4+ atom. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to two equivalent Cu1+ and one C4+ atom. In the second S2- site, S2- is bonded in a 2-coordinate geometry to one Cs1+, one Cu1+, and one C4+ atom. In the third S2- site, S2- is bonded in a distorted water-like geometry to two equivalent Cs1+, one Cu1+, and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Plutonium Retention by Crystalline Silicotitanate under Hyperalkaline Conditions Relevant to Tank-Side Cesium-Removal at the Hanford Site

Crystalline silicotitanate (CST) is used in Hanford’s Tank-Side Cesium-Removal (TSCR) process to selectively remove Cs-137 from highly caustic, nitrate-rich tank supernatants. Recent testing with actual waste samples suggests that CST can also retain measurable plutonium (Pu), which could affect radiological classification and disposal pathways for spent CST. To quantify this behavior, Pu partitioning to CST was studied under Hanford-relevant conditions using batch-contact experiments in a representative simulant (2 M NaNO3, 0.7 M NaOH). Isotherm data were measured and distribution ratios calculated, with Cs+ uptake used as benchmark. Under low-carbonate conditions, Pu was retained strongly by CST in systems initially contacted with either PuO2 nanoparticles (Pu(IV)) or aqueous Pu(VI), with distribution ratios of ~2,200–3,700 mL/g, generally exceeding those for Cs+ (~400–1,000 mL/g). Increasing carbonate concentration strongly reduced PuO2 nanoparticle retention; at [Na2CO3] = 1 M, distribution ratios decreased by up to one order of magnitude to roughly 100–300 mL/g. Electron microscopy suggests that Pu retention involves a combination of mechanisms such as PuO2 NP aggregation induced by CST leachate components, and association with CST bead surfaces.

Neumann, J.↗