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All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Coarse-Grained Simulations of Polyrotaxane Hydrogels under Quiescent and Shear Conditions

Cyclodextrin-based polyrotaxanes (PR) form hydrogels in water through cyclodextrin (CD) aggregation and crystallization. These networks can break under shear flows, making them versatile platforms for extrusion-based 3D printing. To optimize the material properties of 3D-printed PR gels, a microscopic understanding of the structural evolution during 3D printing is necessary. Here, we employ coarse-grained (CG) simulations to reveal the PR assembly process at the molecular level. Our simulations reproduce the experimental crystal morphologies of PR at varying concentrations and chain lengths under quiescent conditions. Using nonequilibrium simulations, we show shear flow ruptures crystalline domain connectivity in PR gels and stacks the lamellae in the gradient direction, allowing the materials to flow during 3D printing. After the cessation of flow, the anisotropic crystal alignment and absence of available dangling PR diminish the intercrystal connectivity. The printed materials are therefore mechanically weaker than the pristine hydrogels, in agreement with experimental results. Nonetheless, by relating the microscopic structural evolution with viscoelastic properties of PR gels and solutions, we elucidate how flow conditions and sample composition affect the 3D printing performance of PR hydrogels.

Smith, Cameron D. [Dartmouth College, Hanover, NH ↗
DOE OSTI2021

CO2 refixation is higher in leaves of woody species with high mesophyll and stomatal resistances to CO2 diffusion

Abstract The percentage of respiratory and photorespiratory CO2 refixed in leaves (Pr) represents part of the CO2 used in photosynthesis. The importance of Pr as well as differences between species and functional types are still not well investigated. In this study, we examine how Pr differs between six temperate and boreal woody species: Betula pendula, Quercus robur, Larix decidua, Pinus sylvestris, Picea abies and Vaccinium vitis-idaea. The study covers early and late successional species, deciduous broadleaves, deciduous conifers, evergreen conifers and evergreen broadleaves. We investigated whether some species or functional types had higher refixation percentages than others, whether leaf traits could predict higher Pr and whether these traits and their impact on Pr changed during growing seasons. Photosynthesis CO2 response (A/Ci)-curves, measured early, mid and late season, were used to estimate and compare Pr, mesophyll resistance (rm) and stomatal resistance (rs) to CO2 diffusion. Additionally, light images and transmission electron microscope images were used to approximate the fraction of intercellular airspace and cell wall thickness. We found that evergreens, especially late successional species, refixed a significantly higher amount of CO2 than the other species throughout the entire growing season. In addition, rm, rs and leaf mass per area, traits that typically are higher in evergreen species, were also significantly, positively correlated with Pr. We suggest that this is due to higher rm decreasing diffusion of (photo) respiratory CO2 out of the leaf. Cell wall thickness had a positive effect on Pr and rm, while the fraction of intercellular airspace had no effect. Both were significantly different between evergreen conifers and other types. Our findings suggest that species with a higher rm use a greater fraction of mitochondria-derived CO2, especially when stomatal conductance is low. This should be taken into account when modeling the overall CO2 fertilization effect for terrestrial ecosystems dominated by high rm species.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

GIF Supercritical Water Cooled Reactor: Proliferation Resistance and Physical Protection White Paper

This report is part of a series of six white papers, prepared jointly by the Proliferation Resistance and Physical Protection Working Group (PRPPWG) and the six System Steering Committees (SSCs) and provisional System Steering Committees (pSSCs). This publication is an update to a similar series published in 2011 presenting the status of Proliferation Resistance & Physical Protection (PR&PP) characteristics for each of the six systems selected by the Generation IV International Forum (GIF) for further research and development, namely: the Sodium-cooled fast Reactor (SFR), the Very high temperature reactor (VHTR), the gas-cooled fast reactor (GFR), the Molten salt reactor (MSR) and the Supercritical water–cooled reactor (SCWR). This white paper represents the status of Proliferation Resistance and Physical Protection (PR&PP) characteristics for the Supercritical Water-cooled Fast reactor (SCFR) reference designs selected by the Generation IV International Forum (GIF) SCWR System Steering Committee (SSC). The intent is to generate preliminary information about the PR&PP features of the SCWR reactor technology and to provide insights for optimizing their PR&PP performance for the benefit of SCWR system designers. It updates the SCWR analysis published in the 2011 report “Proliferation Resistance and Physical Protection of the Six Generation IV Nuclear Energy Systems”, prepared Jointly by the Proliferation Resistance and Physical Protection Working Group (PRPPWG) and the System Steering Committees and provisional System Steering Committees of the Generation IV International Forum, taking into account the evolution of both the systems, the GIF R&D activities, and an increased understanding of the PR&PP features. The white paper, prepared jointly by the GIF PRPPWG and the GIF SCWR SSC, follows the highlevel paradigm of the GIF PR&PP Evaluation Methodology to investigate the PR&PP features of the eight proposed GIF SCWR designs. Two small modular reactors, the Canadian SSR and the Canada/China/Europe ECC-SMART are also mentioned. An overview of the fuel cycles for the GIF designs are provided. For PR, the document analyses and discusses the proliferation resistance aspects in terms of robustness against State-based threats associated with diversion of materials, misuse of facilities, breakout scenarios, and production in clandestine facilities. Similarly, for PP, the document discusses the robustness against theft of material and sabotage by non-State actors. The document follows a common template adopted by all the white papers in the updated series.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

GIF Very High Temperature Reactor: Proliferation Resistance and Physical Protection White Paper

This report is part of a series of six white papers, prepared jointly by the Proliferation Resistance and Physical Protection Working Group (PRPPWG) and the six System Steering Committees (SSCs) and provisional System Steering Committees (pSSCs). This publication is an update to a similar series published in 2011 presenting the status of Proliferation Resistance & Physical Protection (PR&PP) characteristics for each of the six systems selected by the Generation IV International Forum (GIF) for further research and development, namely: the Sodium-cooled fast Reactor (SFR), the Very high temperature reactor (VHTR), the gas-cooled fast reactor (GFR), the Molten salt reactor (MSR) and the Supercritical water–cooled reactor (SCWR). This white paper represents the status of Proliferation Resistance and Physical Protection (PR&PP) characteristics for the Very-High-Temperature Reactor (VHTR) reference designs selected by the Generation IV International Forum (GIF) VHTR System Steering Committee (SSC). The intent is to generate preliminary information about the PR&PP features of the VHTR reactor technology and to provide insights for optimizing their PR&PP performance for the benefit of VHTR system designers. It updates the VHTR analysis published in the 2011 report “Proliferation Resistance and Physical Protection of the Six Generation IV Nuclear Energy Systems”, prepared Jointly by the Proliferation Resistance and Physical Protection Working Group (PRPPWG) and the System Steering Committees and provisional System Steering Committees of the Generation IV International Forum, taking into account the evolution of both the systems, the GIF R&D activities, and an increased understanding of the PR&PP features. The white paper, prepared jointly by the GIF PRPPWG and the GIF VHTR SSC, follows the high-level paradigm of the GIF PR&PP Evaluation Methodology to investigate the key points of PR&PP features extracted from the reference designs of VHTRs under consideration in various countries. A major update from the 2011 report is an explicit distinction between prismatic block-type VHTRs and pebble-bed VHTRs. The white paper also provides an overview of the TRISO fuel and fuel cycle. For PR, the document analyses and discusses the proliferation resistance aspects in terms of robustness against State-based threats associated with diversion of materials, misuse of facilities, breakout scenarios, and production in clandestine facilities. Similarly, for PP, the document discusses the robustness against theft of material and sabotage by non-State actors. The document follows a common template adopted by all the white papers in the updated series.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRS2006

TRMM On-Orbit Performance Re-Accessed After Control Change

The Tropical Rainfall Measuring Mission (TRMM) spacecraft, a joint mission between the U.S. and Japan, launched onboard an HI1 rocket on November 27,1997 and transitioned in August, 2001 from an average operating altitude of 350 kilometers to 402.5 kilometers. Due to problems using the Earth Sensor Assembly (ESA) at the higher altitude, TRMM switched to a backup attitude control mode. Prior to the orbit boost TRMM controlled pitch and roll to the local vertical using ESA measurements while using gyro data to propagate yaw attitude between yaw updates from the Sun sensors. After the orbit boost, a Kalman filter used 3-axis gyro data with Sun sensor and magnetometers to estimate onboard attitude. While originally intended to meet a degraded attitude accuracy of 0.7 degrees, the new control mode met the original 0.2 degree attitude accuracy requirement after improving onboard ephemeris prediction and adjusting the magnetometer calibration onboard. Independent roll attitude checks using a science instrument, the Precipitation Radar (PR) which was built in Japan, provided a novel insight into the pointing performance. The PR data helped identify the pointing errors after the orbit boost, track the performance improvements, and show subtle effects from ephemeris errors and gyro bias errors. It also helped identify average bias trends throughout the mission. Roll errors tracked by the PR from sample orbits pre-boost and post-boost are shown in Figure 1. Prior to the orbit boost the largest attitude errors were due to occasional interference in the ESA. These errors were sometime larger than 0.2 degrees in pitch and roll, but usually less, as estimated from a comprehensive review of the attitude excursions using gyro data. Sudden jumps in the onboard roll show up as spikes in the reported attitude since the control responds within tens of seconds to null the pointing error. The PR estimated roll tracks well with an estimate of the roll history propagated using gyro data. After the orbit boost, the attitude errors shown by the PR roll have a smooth sine-wave type signal because of the way that attitude errors propagate with the use of gyro data. Yaw errors couple at orbit period to roll with '/4 orbit lag. By tracking the amplitude, phase, and bias of the sinusoidal PR roll error signal, it was shown that the average pitch rotation axis tends to be offset from orbit normal in a direction perpendicular to the Sun direction, as shown in Figure 2 for a 200 day period following the orbit boost. This is a result of the higher accuracy and stability of the Sun sensor measurements relative to the magnetometer measurements used in the Kalman filter. In November, 2001 a magnetometer calibration adjustment was uploaded which improved the pointing performance, keeping the roll and yaw amplitudes within about 0.1 degrees. After the boost, onboard ephemeris errors had a direct effect on the pitch pointing, being used to compute the Earth pointing reference frame. Improvements after the orbit boost have kept the the onboard ephemeris errors generally below 20 kilometers. Ephemeris errors have secondary effects on roll and yaw, especially during high beta angle when pitch effects can couple into roll and yaw. This is illustrated in figure 3. The onboard roll bias trends as measured by PR data show correlations with the Kalman filter's gyro bias error. This particularly shows up after yaw turns (every 2 to 4 weeks) as shown in Figure 3, when a slight roll bias is observed while the onboard computed gyro biases settle to new values. As for longer term trends, the PR data shows that the roll bias was influenced by Earth horizon radiance effects prior to the boost, changing values at yaw turns, and indicated a long term drift as shown in Figure 4. After the boost, the bias variations were smaller and showed some possible correlation with solar beta angle, probably due to sun sensor misalignment effects.

Bilanow, Steve↗
NASA NTRSDate not supplied

Desert Research and Technology Studies (D-RATS) 2022 Quicklook Report

This report summarizes the Desert Research and Technology Studies (D-RATS) 2022 analog tests. BACKGROUND - Artemis Challenges – NASA’s concept of operations (ConOps) for the Artemis mission architecture brings new challenges for human exploration of the lunar surface, including: (1) Low-angle, natural lighting at lunar poles; and (2) Exploration sites that challenge communication with Earth. - International Partner Involvement – NASA is working with the Japan Aerospace Exploration Agency (JAXA) to scope mission & functional requirements for an Artemis Pressurized Rover (PR), which JAXA may provide. - Charter – HQ Exploration Systems Development Mission Directorate (ESDMD) Moon to Mars Architecture Development Office (M2MADO) Strategy and Architectures (SA) chartered the Human-in-the-Loop (HITL) test team to investigate Artemis architectural questions related to pressurized rover ConOps. - Rationale – to inform the NASA/JAXA pressurized rover study-agreement. PLAN - Objectives – Analog tests conducted in October 2022 by the D-RATS team addressed three high-level objectives: 1. Investigate pressurized rover (PR) ConOps and capabilities for Artemis exploration 2. Integrate with JAXA engineers & astronauts and incorporate JAXA PR design elements into testing. 3. Re-establish analog field-testing skills & capabilities with rovers to investigate Artemis architecture ConOps. - Secondary Objectives – Work with other groups to leverage D-RATS field test for additional objectives. 4. Work with the Public Affairs Office (PAO) to perform D-RATS public outreach activities. 5. Coordinate with the Human Physiology Performance Protection & Operations (H-3PO) team to facilitate in-field evaluation of human health and performance (HHP) objectives. 6. Share D-RATS field-site and assets with Lunar LTE Studies (Lunar LiTES) team, to aid their study of the use of 4G/LTE communication protocols and devices for astronauts and robotic nodes on the lunar surface. - Team – Fully integrated test team comprised of members from 5 NASA centers, JAXA, and the United States Geological Survey (USGS) - Location – Black Point Lava Flow, ~40 miles north of Flagstaff, AZ HIGH-LEVEL OBJECTIVES ACCOMPLISHED - Investigated Pressurized Rover ConOps & Capabilities for Artemis Exploration (Objective 1) - Completed testing with 4 crew pairs, each spending 3 days and 2 nights in the rover conducting Artemis PR dayin-the-life activities (2 JAXA astronauts, 2 JAXA engineers, 1 NASA astronaut, 3 NASA engineers). - Collected detailed objective & subjective data supporting 10 strategic questions related to Artemis PR operations. - Field geologists present in field observed rover operations & EVAs. - Science team in Houston MCC communicated directly with crew. - Demonstrated crew-led and MCC-led PR teleoperation use cases during EVAs. - Integrated with JAXA Engineers & Astronauts and Incorporated JAXA PR Design Elements into Testing (Objective 2) - NASA & JAXA engineers, flight controllers, scientists, roboticists, and astronauts directly participated in and/or observed testing both in field and in MCC-Houston. - Incorporated JAXA PR design elements into both integrated and standalone testing at JSC and in the field. - Re-established Analog Field-Testing Skills & Capabilities with Rovers to Investigate Artemis Architecture ConOps (Objective 3) - Multiple teams successfully worked to establish and manage field-test base camp, monitor and maintain the rover, and plan and execute 2 weeks of consecutive field-testing with little to no breaks between crews. TEST OUTCOMES - Results will inform Artemis architecture ConOps & capabilities related to pressurized rover operations (see sections 2 for more details) - Summary and team detailed reports will be posted on the D-RATS 2022 wiki

Analog↗
DOE OSTI2020

Materials Data on PrNiGe3 by Materials Project

PrNiGe3 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Pr is bonded in a 4-coordinate geometry to four equivalent Ni and ten Ge atoms. All Pr–Ni bond lengths are 3.24 Å. There are a spread of Pr–Ge bond distances ranging from 3.14–3.29 Å. Ni is bonded in a 9-coordinate geometry to four equivalent Pr and five Ge atoms. There are a spread of Ni–Ge bond distances ranging from 2.36–2.39 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 2-coordinate geometry to two equivalent Pr, two equivalent Ni, and five Ge atoms. There are one shorter (2.49 Å) and four longer (2.96 Å) Ge–Ge bond lengths. In the second Ge site, Ge is bonded in a 2-coordinate geometry to two equivalent Pr, two equivalent Ni, and five Ge atoms. The Ge–Ge bond length is 2.49 Å. In the third Ge site, Ge is bonded in a 1-coordinate geometry to six equivalent Pr, one Ni, and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.57 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrCu6 by Materials Project

PrCu6 is Bergman Structure: Mg32(Al,Zn)49 Bergman-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Pr is bonded in a 6-coordinate geometry to nineteen Cu atoms. There are a spread of Pr–Cu bond distances ranging from 2.90–3.38 Å. There are five inequivalent Cu sites. In the first Cu site, Cu is bonded in a 2-coordinate geometry to four equivalent Pr and ten Cu atoms. There are a spread of Cu–Cu bond distances ranging from 2.53–3.10 Å. In the second Cu site, Cu is bonded to three equivalent Pr and nine Cu atoms to form a mixture of face, edge, and corner-sharing CuPr3Cu9 cuboctahedra. There are a spread of Cu–Cu bond distances ranging from 2.47–2.61 Å. In the third Cu site, Cu is bonded in a 3-coordinate geometry to three equivalent Pr and eight Cu atoms. There are two shorter (2.51 Å) and one longer (2.85 Å) Cu–Cu bond lengths. In the fourth Cu site, Cu is bonded in a 12-coordinate geometry to three equivalent Pr and nine Cu atoms. There are a spread of Cu–Cu bond distances ranging from 2.46–3.03 Å. In the fifth Cu site, Cu is bonded to three equivalent Pr and nine Cu atoms to form a mixture of face, edge, and corner-sharing CuPr3Cu9 cuboctahedra. There are one shorter (2.49 Å) and one longer (2.60 Å) Cu–Cu bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrMg12 by Materials Project

PrMg12 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are three inequivalent Mg sites. In the first Mg site, Mg is bonded to ten Mg and two equivalent Pr atoms to form a mixture of distorted corner, edge, and face-sharing MgPr2Mg10 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 2.93–3.16 Å. Both Mg–Pr bond lengths are 3.94 Å. In the second Mg site, Mg is bonded in a distorted q6 geometry to ten Mg and two equivalent Pr atoms. There are a spread of Mg–Mg bond distances ranging from 3.12–3.35 Å. Both Mg–Pr bond lengths are 3.66 Å. In the third Mg site, Mg is bonded in a 10-coordinate geometry to nine Mg and one Pr atom. The Mg–Mg bond length is 3.06 Å. The Mg–Pr bond length is 3.65 Å. Pr is bonded in a 12-coordinate geometry to twenty Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr7BP2O17 by Materials Project

Pr7BP2O17 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are seven inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded to seven O2- atoms to form distorted PrO7 pentagonal bipyramids that share corners with three PO4 tetrahedra and an edgeedge with one PrO7 pentagonal bipyramid. There are a spread of Pr–O bond distances ranging from 2.31–2.59 Å. In the second Pr3+ site, Pr3+ is bonded to seven O2- atoms to form distorted PrO7 pentagonal bipyramids that share corners with two equivalent PO4 tetrahedra and an edgeedge with one PrO7 pentagonal bipyramid. There are a spread of Pr–O bond distances ranging from 2.35–2.62 Å. In the third Pr3+ site, Pr3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.37–2.70 Å. In the fourth Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.37–2.63 Å. In the fifth Pr3+ site, Pr3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.30–2.82 Å. In the sixth Pr3+ site, Pr3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.28–2.89 Å. In the seventh Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.34–2.78 Å. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.38–1.42 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent PrO7 pentagonal bipyramids. There is three shorter (1.55 Å) and one longer (1.57 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three PrO7 pentagonal bipyramids. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. There are seventeen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three Pr3+ and one B3+ atom. In the second O2- site, O2- is bonded to four Pr3+ atoms to form a mixture of distorted corner and edge-sharing OPr4 tetrahedra. In the third O2- site, O2- is bonded to four Pr3+ atoms to form a mixture of corner and edge-sharing OPr4 tetrahedra. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to three Pr3+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two Pr3+ and one P5+ atom. In the sixth O2- site, O2- is bonded to four Pr3+ atoms to form a mixture of corner and edge-sharing OPr4 tetrahedra. In the seventh O2- site, O2- is bonded to four Pr3+ atoms to form a mixture of corner and edge-sharing OPr4 tetrahedra. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one B3+ atom. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one P5+ atom. In the eleventh O2- site, O2- is bonded to four Pr3+ atoms to form a mixture of corner and edge-sharing OPr4 tetrahedra. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to three Pr3+ and one B3+ atom. In the thirteenth O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded to four Pr3+ atoms to form a mixture of corner and edge-sharing OPr4 tetrahedra. In the fifteenth O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrAl22O34 by Materials Project

PrAl22O34 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. Pr is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Pr–O bond distances ranging from 2.54–3.24 Å. There are eighteen inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.09 Å. In the second Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–59°. There is three shorter (1.82 Å) and one longer (1.83 Å) Al–O bond length. In the third Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with six AlO6 octahedra and a cornercorner with one AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Al–O bond distances ranging from 1.74–1.83 Å. In the fourth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.09 Å. In the fifth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.81–2.09 Å. In the sixth Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Al–O bond distances ranging from 1.81–1.85 Å. In the seventh Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–59°. There is three shorter (1.81 Å) and one longer (1.82 Å) Al–O bond length. In the eighth Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with six AlO6 octahedra and a cornercorner with one AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–54°. There is one shorter (1.72 Å) and three longer (1.79 Å) Al–O bond length. In the ninth Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with six AlO6 octahedra and a cornercorner with one AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Al–O bond distances ranging from 1.71–1.83 Å. In the tenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.83–2.05 Å. In the eleventh Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.01 Å. In the twelfth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.83–2.04 Å. In the thirteenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with six AlO6 octahedra. There is four shorter (1.90 Å) and two longer (1.91 Å) Al–O bond length. In the fourteenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.01 Å. In the fifteenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.81–2.08 Å. In the sixteenth Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with six AlO6 octahedra and a cornercorner with one AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–54°. There are a spread of Al–O bond distances ranging from 1.75–1.79 Å. In the seventeenth Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Al–O bond distances ranging from 1.81–1.86 Å. In the eighteenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–1.95 Å. There are twenty-six inequivalent O sites. In the first O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the second O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the third O site, O is bonded in a trigonal non-coplanar geometry to three Al atoms. In the fourth O site, O is bonded in a trigonal planar geometry to three Al atoms. In the fifth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the sixth O site, O is bonded in a trigonal planar geometry to three Al atoms. In the seventh O site, O is bonded in a trigonal planar geometry to three Al atoms. In the eighth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent Pr and two Al atoms. In the tenth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the eleventh O site, O is bonded in a trigonal planar geometry to three Al atoms. In the twelfth O site, O is bonded in a trigonal non-coplanar geometry to three Al atoms. In the thirteenth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the fourteenth O site, O is bonded in a 4-coordinate geometry to one Pr and three Al atoms. In the fifteenth O site, O is bonded in a trigonal planar geometry to three Al atoms. In the sixteenth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the seventeenth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the eighteenth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the nineteenth O site, O is bonded to one Pr and three Al atoms to form distorted corner-sharing OPrAl3 tetrahedra. In the twentieth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the twenty-first O site, O is bonded in a trigonal non-coplanar geometry to three Al atoms. In the twenty-second O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the twenty-third O site, O is bonded to one Pr and three Al atoms to form distorted corner-sharing OPrAl3 tetrahedra. In the twenty-fourth O site, O is bonded in a trigonal planar geometry to three Al atoms. In the twenty-fifth O site, O is bonded in a 2-coordinate geometry to one Pr and two Al atoms. In the twenty-sixth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrTm3 by Materials Project

Tm3Pr is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are three inequivalent Tm sites. In the first Tm site, Tm is bonded to eight Tm and four equivalent Pr atoms to form TmPr4Tm8 cuboctahedra that share corners with four equivalent PrTm12 cuboctahedra, corners with fourteen TmPr4Tm8 cuboctahedra, edges with six equivalent PrTm12 cuboctahedra, edges with twelve TmPr4Tm8 cuboctahedra, faces with four equivalent PrTm12 cuboctahedra, and faces with sixteen TmPr4Tm8 cuboctahedra. There are a spread of Tm–Tm bond distances ranging from 3.50–3.66 Å. There are two shorter (3.53 Å) and two longer (3.61 Å) Tm–Pr bond lengths. In the second Tm site, Tm is bonded to eight Tm and four equivalent Pr atoms to form TmPr4Tm8 cuboctahedra that share corners with four equivalent PrTm12 cuboctahedra, corners with fourteen TmPr4Tm8 cuboctahedra, edges with six equivalent PrTm12 cuboctahedra, edges with twelve TmPr4Tm8 cuboctahedra, faces with four equivalent PrTm12 cuboctahedra, and faces with sixteen TmPr4Tm8 cuboctahedra. There are a spread of Tm–Tm bond distances ranging from 3.50–3.66 Å. There are two shorter (3.53 Å) and two longer (3.61 Å) Tm–Pr bond lengths. In the third Tm site, Tm is bonded to eight Tm and four equivalent Pr atoms to form TmPr4Tm8 cuboctahedra that share corners with four equivalent PrTm12 cuboctahedra, corners with fourteen TmPr4Tm8 cuboctahedra, edges with six equivalent PrTm12 cuboctahedra, edges with twelve TmPr4Tm8 cuboctahedra, faces with four equivalent PrTm12 cuboctahedra, and faces with sixteen TmPr4Tm8 cuboctahedra. There are one shorter (3.56 Å) and one longer (3.66 Å) Tm–Tm bond lengths. There are two shorter (3.53 Å) and two longer (3.61 Å) Tm–Pr bond lengths. Pr is bonded to twelve Tm atoms to form PrTm12 cuboctahedra that share corners with six equivalent PrTm12 cuboctahedra, corners with twelve TmPr4Tm8 cuboctahedra, edges with eighteen TmPr4Tm8 cuboctahedra, faces with eight equivalent PrTm12 cuboctahedra, and faces with twelve TmPr4Tm8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrAl4Co by Materials Project

PrCoAl4 crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. Pr is bonded in a 1-coordinate geometry to one Co and twelve Al atoms. The Pr–Co bond length is 2.99 Å. There are a spread of Pr–Al bond distances ranging from 3.11–3.28 Å. Co is bonded in a 9-coordinate geometry to one Pr and eight Al atoms. There are a spread of Co–Al bond distances ranging from 2.30–2.57 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a distorted linear geometry to two equivalent Pr, two equivalent Co, and eight Al atoms. There are four shorter (2.80 Å) and four longer (2.94 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 4-coordinate geometry to two equivalent Pr, two equivalent Co, and eight Al atoms. There are two shorter (2.72 Å) and two longer (3.04 Å) Al–Al bond lengths. In the third Al site, Al is bonded in a 12-coordinate geometry to four equivalent Pr, two equivalent Co, and six Al atoms. There are one shorter (2.75 Å) and one longer (2.98 Å) Al–Al bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrLu3 by Materials Project

Lu3Pr is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are three inequivalent Lu sites. In the first Lu site, Lu is bonded to eight Lu and four equivalent Pr atoms to form LuPr4Lu8 cuboctahedra that share corners with four equivalent PrLu12 cuboctahedra, corners with fourteen equivalent LuPr4Lu8 cuboctahedra, edges with six equivalent PrLu12 cuboctahedra, edges with twelve LuPr4Lu8 cuboctahedra, faces with four equivalent PrLu12 cuboctahedra, and faces with sixteen LuPr4Lu8 cuboctahedra. There are a spread of Lu–Lu bond distances ranging from 3.47–3.64 Å. There are two shorter (3.51 Å) and two longer (3.58 Å) Lu–Pr bond lengths. In the second Lu site, Lu is bonded to eight Lu and four equivalent Pr atoms to form LuPr4Lu8 cuboctahedra that share corners with four equivalent PrLu12 cuboctahedra, corners with fourteen LuPr4Lu8 cuboctahedra, edges with six equivalent PrLu12 cuboctahedra, edges with twelve LuPr4Lu8 cuboctahedra, faces with four equivalent PrLu12 cuboctahedra, and faces with sixteen LuPr4Lu8 cuboctahedra. There are a spread of Lu–Lu bond distances ranging from 3.47–3.64 Å. There are two shorter (3.51 Å) and two longer (3.58 Å) Lu–Pr bond lengths. In the third Lu site, Lu is bonded to eight Lu and four equivalent Pr atoms to form LuPr4Lu8 cuboctahedra that share corners with four equivalent PrLu12 cuboctahedra, corners with fourteen LuPr4Lu8 cuboctahedra, edges with six equivalent PrLu12 cuboctahedra, edges with twelve LuPr4Lu8 cuboctahedra, faces with four equivalent PrLu12 cuboctahedra, and faces with sixteen LuPr4Lu8 cuboctahedra. There are two shorter (3.51 Å) and two longer (3.58 Å) Lu–Pr bond lengths. Pr is bonded to twelve Lu atoms to form PrLu12 cuboctahedra that share corners with six equivalent PrLu12 cuboctahedra, corners with twelve LuPr4Lu8 cuboctahedra, edges with eighteen LuPr4Lu8 cuboctahedra, faces with eight equivalent PrLu12 cuboctahedra, and faces with twelve LuPr4Lu8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr2Al2Co15 by Materials Project

Pr2Co15Al2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pr is bonded in a 3-coordinate geometry to eighteen Co and one Al atom. There are a spread of Pr–Co bond distances ranging from 2.96–3.34 Å. The Pr–Al bond length is 3.06 Å. There are three inequivalent Co sites. In the first Co site, Co is bonded in a 12-coordinate geometry to two equivalent Pr, eight Co, and two equivalent Al atoms. There are four shorter (2.41 Å) and four longer (2.42 Å) Co–Co bond lengths. Both Co–Al bond lengths are 2.55 Å. In the second Co site, Co is bonded in a distorted q6 geometry to two equivalent Pr, eight Co, and two equivalent Al atoms. There are a spread of Co–Co bond distances ranging from 2.38–2.61 Å. Both Co–Al bond lengths are 2.71 Å. In the third Co site, Co is bonded to three equivalent Pr, eight Co, and one Al atom to form a mixture of distorted edge, corner, and face-sharing CoPr3AlCo8 cuboctahedra. Both Co–Co bond lengths are 2.49 Å. The Co–Al bond length is 2.58 Å. Al is bonded in a 6-coordinate geometry to one Pr, twelve Co, and one Al atom. The Al–Al bond length is 2.60 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaPr9Si6(SO12)2 by Materials Project

NaPr9Si6(SO12)2 crystallizes in the trigonal P3 space group. The structure is three-dimensional. Na1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Na–O bond distances ranging from 2.52–2.97 Å. There are five inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 8-coordinate geometry to two S2- and six O2- atoms. There are one shorter (2.98 Å) and one longer (3.02 Å) Pr–S bond lengths. There are a spread of Pr–O bond distances ranging from 2.39–2.94 Å. In the second Pr3+ site, Pr3+ is bonded in a 5-coordinate geometry to two S2- and five O2- atoms. There are one shorter (3.02 Å) and one longer (3.03 Å) Pr–S bond lengths. There are a spread of Pr–O bond distances ranging from 2.35–2.58 Å. In the third Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.43–2.75 Å. In the fourth Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.44–2.77 Å. In the fifth Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.45–2.81 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the second Si4+ site, Si4+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.64 Å) and two longer (1.65 Å) Si–O bond length. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 12-coordinate geometry to six Pr3+ and six O2- atoms. There are three shorter (3.14 Å) and three longer (3.26 Å) S–O bond lengths. In the second S2- site, S2- is bonded in a distorted octahedral geometry to six Pr3+ atoms. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, two Pr3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two Pr3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, two Pr3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+, one Si4+, and one S2- atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, two Pr3+, one Si4+, and one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr2FeSi3 by Materials Project

Pr2FeSi3 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Pr is bonded to three equivalent Fe and nine Si atoms to form a mixture of edge and face-sharing PrFe3Si9 cuboctahedra. All Pr–Fe bond lengths are 3.16 Å. There are three shorter (3.16 Å) and six longer (3.24 Å) Pr–Si bond lengths. Fe is bonded in a 3-coordinate geometry to six equivalent Pr and three equivalent Si atoms. All Fe–Si bond lengths are 2.34 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to six equivalent Pr and three equivalent Si atoms. All Si–Si bond lengths are 2.34 Å. In the second Si site, Si is bonded in a 3-coordinate geometry to six equivalent Pr and three equivalent Fe atoms. In the third Si site, Si is bonded in a 9-coordinate geometry to six equivalent Pr and three equivalent Si atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrAl4Ni by Materials Project

PrNiAl4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Pr is bonded in a 9-coordinate geometry to two equivalent Ni and thirteen Al atoms. Both Pr–Ni bond lengths are 3.32 Å. There are a spread of Pr–Al bond distances ranging from 3.04–3.34 Å. Ni is bonded in a 7-coordinate geometry to two equivalent Pr and seven Al atoms. There are a spread of Ni–Al bond distances ranging from 2.31–2.51 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to four equivalent Pr and six Al atoms. There are four shorter (2.92 Å) and two longer (3.06 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a distorted single-bond geometry to three equivalent Pr, one Ni, and four equivalent Al atoms. In the third Al site, Al is bonded in a 3-coordinate geometry to three equivalent Pr, three equivalent Ni, and one Al atom.

36 MATERIALS SCIENCE↗