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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Pr(MnSn)6 by Materials Project

Pr(MnSn)6 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Pr sites. In the first Pr site, Pr is bonded to eight Sn atoms to form distorted edge-sharing PrSn8 hexagonal bipyramids. There are a spread of Pr–Sn bond distances ranging from 3.08–3.23 Å. In the second Pr site, Pr is bonded to eight Sn atoms to form distorted edge-sharing PrSn8 hexagonal bipyramids. There are a spread of Pr–Sn bond distances ranging from 3.07–3.21 Å. There are four inequivalent Mn sites. In the first Mn site, Mn is bonded in a 12-coordinate geometry to six Sn atoms. There are four shorter (2.79 Å) and two longer (2.87 Å) Mn–Sn bond lengths. In the second Mn site, Mn is bonded in a 12-coordinate geometry to six Sn atoms. There are a spread of Mn–Sn bond distances ranging from 2.77–2.87 Å. In the third Mn site, Mn is bonded in a 12-coordinate geometry to six Sn atoms. There are a spread of Mn–Sn bond distances ranging from 2.74–2.87 Å. In the fourth Mn site, Mn is bonded in a 12-coordinate geometry to six Sn atoms. There are a spread of Mn–Sn bond distances ranging from 2.77–2.87 Å. There are nine inequivalent Sn sites. In the first Sn site, Sn is bonded in a 12-coordinate geometry to three Pr and six Mn atoms. In the second Sn site, Sn is bonded in a 6-coordinate geometry to six Mn atoms. In the third Sn site, Sn is bonded in a 12-coordinate geometry to three Pr and six Mn atoms. In the fourth Sn site, Sn is bonded in a 6-coordinate geometry to six Mn atoms. In the fifth Sn site, Sn is bonded in a 8-coordinate geometry to two equivalent Pr and six Mn atoms. In the sixth Sn site, Sn is bonded in a 7-coordinate geometry to one Pr and six Mn atoms. In the seventh Sn site, Sn is bonded in a 8-coordinate geometry to one Pr, six Mn, and one Sn atom. The Sn–Sn bond length is 3.02 Å. In the eighth Sn site, Sn is bonded in a 8-coordinate geometry to one Pr, six Mn, and one Sn atom. The Sn–Pr bond length is 3.07 Å. All Sn–Mn bond lengths are 2.87 Å. The Sn–Sn bond length is 3.02 Å. In the ninth Sn site, Sn is bonded in a 8-coordinate geometry to one Pr, six Mn, and one Sn atom. The Sn–Sn bond length is 3.01 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Quantum paramagnetism in a non-Kramers rare-earth oxide: Monoclinic Pr 2 Ti 2 O 7

Little is so far known about the magnetism of the A 2 B 2 O 7 monoclinic layered perovskites that replace the spin-ice supporting pyrochlore structure for r A /r B > 1.78. We show that high quality monoclinic Pr 2 Ti 2 O 7 single crystals with a three-dimensional network of non-Kramers Pr 3+ ions that interact through edge-sharing superexchange interactions, form a singlet ground-state quantum paramagnet that does not undergo any magnetic phase transitions down to, at least, 1.8 K. The chemical phase stability, structure, and magnetic properties of the layered perovskite Pr 2 Ti 2 O 7 were investigated using x-ray diffraction, transmission electron microscopy, and magnetization measurements. Synthesis of polycrystalline samples with the nominal compositions of Pr 2 Ti 2+x O 7 (–0.16 ≤ x ≤ 0.16 ) showed that deviations from the Pr 2 Ti 2 O 7 stoichiometry lead to secondary phases of related structures including the perovskite phase Pr 2/3 TiO 3 and the orthorhombic phases Pr 4 Ti 9 O 24 and Pr 2 TiO 5 . No indications of site disordering (stuffing and antistuffing) or vacancy defects were observed in the Pr 2 Ti 2 O 7 majority phase. A procedure for growth of high-structural-quality stoichiometric single crystals of Pr 2 Ti 2 O 7 by the traveling solvent floating zone method is reported. Thermomagnetic measurements of single-crystalline Pr 2 Ti 2 O 7 reveal an isolated singlet ground state that we associate with the low-symmetry crystal electric-field environments that split the (2J + 1 = 9)-fold degenerate spin-orbital multiplets of the four differently coordinated Pr 3+ ions into 36 isolated singlets resulting in an anisotropic temperature-independent van Vleck susceptibility at low T. Here, a small isotropic Curie term is associated with 0.96(2)% noninteracting Pr 4+ impurities.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr by Materials Project

Pr is alpha La structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Pr sites. In the first Pr site, Pr is bonded to twelve Pr atoms to form a mixture of edge, face, and corner-sharing PrPr12 cuboctahedra. There are six shorter (3.70 Å) and six longer (3.74 Å) Pr–Pr bond lengths. In the second Pr site, Pr is bonded to twelve Pr atoms to form a mixture of edge, face, and corner-sharing PrPr12 cuboctahedra. All Pr–Pr bond lengths are 3.74 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Experimental and modeling studies of PR and ND oxalate solubility to high ionic strengths: Insight into actinide(III) oxalates

Actinide oxalates are chemical compounds important to nuclear industry, ranging from actinide separation in waste reprocessing, to production of specialty actinides, and to disposal of high level nuclear waste (HLW) and spent nuclear fuel (SNF). In this study, the solubility constants for Pr 2 (C 2 O 4 ) 3 •10H 2 O and Nd 2 (C 2 O 4 ) 3 •10H 2 O by performing solubility experiments in HNO 3 and mixtures of HNO 3 and H 2 C 2 O 4 at 23.0 ± 0.2 °C have been determined. The targeted starting materials, Pr 2 (C 2 O 4 ) 3 •10H 2 O and Nd 2 (C 2 O 4 ) 3 •10H 2 O, were successfully synthesized at room temperature using PrCl 3 , NdCl 3 and oxalic acid as the source metrials. Then, we utilized the targeted solubility-controlling phases to conduct solubility measurements. There was no phase change over the entire periods of experiments, demonstrating that Pr 2 (C 2 O 4 ) 3 •10H 2 O and Nd 2 (C 2 O 4 ) 3 •10H 2 O were the solubility-controlling phases in our respective experiments. Based on our experimental data, we have developed a thermodynamic model for Pr 2 (C 2 O 4 ) 3 •10H 2 O and Nd 2 (C 2 O 4 ) 3 •10H 2 O in the mixtures of HNO 3 and H 2 C 2 O 4 to high ionic strengths. The model for Pr 2 (C 2 O 4 ) 3 •10H 2 O reproduces well the reported experimental data for Pu 2 (C 2 O 4 ) 3 •10H 2 O, which are not utilized for the model development, demonstrating that Pr(III) is an excellent analog for Pu(III). Similarly, the model for Nd 2 (C 2 O 4 ) 3 •10H 2 O reproduces the solubility of Am 2 (C 2 O 4 ) 3 •10H 2 O and Cm 2 (C 2 O 4 ) 3 •10H 2 O. The Pitzer model was used for the calculation of activity coefficients. Based on the published, well established model for dissociation constants for oxalic acid and stability constants for actinide-oxalate complexes [i.e., AmC 2 O 4 + , and Am(C 2 O 4 ) 2 - ] to high ionic strengths, we have obtained the solubility constants (log 10 K 0 ) for the following reactions at 25 °C, Pr 2 (C 2 O 4 ) 3 •10H 2 O ⇌ 2Pr 3+ + 3C 2 O 4 2- + 10H 2 O(l). Nd 2 (C 2 O 4 ) 3 •10H 2 O ⇌ 2Nd 3+ + 3C 2 O 4 2- + 10H 2 O(l). to be -30.82 ± 0.30 (2σ), and - 31.14 ± 0.35 (2σ), respectively. These values for can be directly applied to Pu 2 (C 2 O 4 ) 3 •10H 2 O, Am 2 (C 2 O 4 ) 3 •10H 2 O and Cm 2 (C 2 O 4 ) 3 •10H 2 O. The model established for actinide oxalates by this study provides the needed knowledge with regard to solubilities of actinide/REE oxalates at various ionic strengths, and is expected to find applications in many fields, including the geological disposal of nuclear waste and the mobility of REE under the surface conditions, as Pr 2 (C 2 O 4 ) 3 •10H 2 O and Nd 2 (C 2 O 4 ) 3 •10H 2 O can be regarded as the pure Pr and Nd end-members of deveroite, a recently discovered natural REE oxalate with the following stoichiometry, (Ce 1.01 Nd 0.33 La 0.32 Pr 0.11 Y 0.11 Sm 0.01 Pb 0.04 U 0.03 Th 0.01 Ca 0.04 ) 2.01 (C 2 O 4 ) 2.99 •9.99H 2 O. Regarding its importance in the geological disposal of nuclear waste, Am 2 (C 2 O 4 ) 3 •10H 2 O/Pu 2 (C 2 O 4 ) 3 •10H 2 O/Cm 2 (C 2 O 4 ) 3 •10H 2 O can be the source-term phase for actinides, as demonstrated by the instance in the disposal in clay/shale formations. This is exemplified by the stability of Am 2 (C 2 O 4 ) 3 •10H 2 O in comparison with Am(OH) 3 (am), Am(OH) 3 (s) and AmCO 3 (OH)(s) under the relevant geological repository conditions.

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

Materials Data on Pr(Ga4Co)2 by Materials Project

PrCo2Ga8 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to thirteen Ga atoms. There are a spread of Pr–Ga bond distances ranging from 3.13–3.39 Å. There are two inequivalent Co sites. In the first Co site, Co is bonded in a 9-coordinate geometry to nine Ga atoms. There are a spread of Co–Ga bond distances ranging from 2.36–2.67 Å. In the second Co site, Co is bonded in a 9-coordinate geometry to nine Ga atoms. There are a spread of Co–Ga bond distances ranging from 2.32–2.62 Å. There are nine inequivalent Ga sites. In the first Ga site, Ga is bonded in a 2-coordinate geometry to two equivalent Pr, two Co, and eight Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.83–2.92 Å. In the second Ga site, Ga is bonded in a 12-coordinate geometry to four equivalent Co and eight Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.64–2.95 Å. In the third Ga site, Ga is bonded in a 2-coordinate geometry to two equivalent Pr, two equivalent Co, and eight Ga atoms. There are four shorter (2.80 Å) and four longer (2.95 Å) Ga–Ga bond lengths. In the fourth Ga site, Ga is bonded in a 12-coordinate geometry to two equivalent Pr, two equivalent Co, and eight Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.65–3.12 Å. In the fifth Ga site, Ga is bonded in a 12-coordinate geometry to two equivalent Pr, two equivalent Co, and six Ga atoms. There are one shorter (2.69 Å) and one longer (2.82 Å) Ga–Ga bond lengths. In the sixth Ga site, Ga is bonded in a 12-coordinate geometry to two equivalent Pr, two equivalent Co, and eight Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.77–3.03 Å. In the seventh Ga site, Ga is bonded in a 12-coordinate geometry to two equivalent Pr, two equivalent Co, and eight Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.75–3.06 Å. In the eighth Ga site, Ga is bonded in a 12-coordinate geometry to two equivalent Pr, two equivalent Co, and eight Ga atoms. In the ninth Ga site, Ga is bonded in a 1-coordinate geometry to three Co and eight Ga atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr(AlFe)6 by Materials Project

Pr(FeAl)6 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Pr is bonded in a 8-coordinate geometry to twelve Fe and eight Al atoms. There are four shorter (3.26 Å) and eight longer (3.32 Å) Pr–Fe bond lengths. There are a spread of Pr–Al bond distances ranging from 2.93–3.07 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to two equivalent Pr, four Fe, and six Al atoms to form a mixture of distorted face, edge, and corner-sharing FePr2Al6Fe4 cuboctahedra. There are two shorter (2.51 Å) and two longer (2.52 Å) Fe–Fe bond lengths. There are a spread of Fe–Al bond distances ranging from 2.53–2.64 Å. In the second Fe site, Fe is bonded to two equivalent Pr, four equivalent Fe, and six Al atoms to form a mixture of distorted face, edge, and corner-sharing FePr2Al6Fe4 cuboctahedra. There are a spread of Fe–Al bond distances ranging from 2.60–2.73 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Pr, six Fe, and three Al atoms. There are one shorter (2.65 Å) and two longer (2.82 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 7-coordinate geometry to one Pr, six Fe, and two equivalent Al atoms. Both Al–Al bond lengths are 2.96 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Pr, six Fe, and four Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr(GePt)2 by Materials Project

Pr(PtGe)2 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to eight Pt and eight Ge atoms. There are a spread of Pr–Pt bond distances ranging from 3.30–3.44 Å. There are a spread of Pr–Ge bond distances ranging from 3.27–3.42 Å. There are two inequivalent Pt sites. In the first Pt site, Pt is bonded in a 9-coordinate geometry to four equivalent Pr and five Ge atoms. There are one shorter (2.48 Å) and four longer (2.53 Å) Pt–Ge bond lengths. In the second Pt site, Pt is bonded in a 4-coordinate geometry to four equivalent Pr and four equivalent Ge atoms. There are a spread of Pt–Ge bond distances ranging from 2.56–2.58 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to four equivalent Pr and five Pt atoms. In the second Ge site, Ge is bonded in a 4-coordinate geometry to four equivalent Pr and four equivalent Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Improving the performance for direct electrolysis of CO 2 in solid oxide electrolysis cells with a Sr 1.9 Fe 1.5 Mo 0.5 O 6– δ electrode via infiltration of Pr 6 O 11 nanoparticles

Direct CO 2 electrolysis using solid oxide electrolysis cells (CO 2 -SOECs) holds promise to efficiently convert carbon dioxide to carbon monoxide and oxygen. Cathodes with desirable catalytic activity and chemical stability play a critical role in the development of direct CO 2 -SOECs. Although Sr 2 Fe 1.5 Mo 0.5 O 6–δ (SFM) has exhibited promise for direct CO 2 -SOECs due to its redox stability, it suffers from insufficient activity for the CO 2 reduction reaction (CO 2 RR). Here we report interface engineering of nanosized Pr 6 O 11 on the SFM cathode obtained through infiltration to promote the CO 2 RR performance for direct CO 2 -SOECs. The effect of Pr 6 O 11 loading on the performance of the CO 2 RR is systematically investigated. At 800 °C, the current density of the Pr 6 O 11 infiltrated SFM cathode with an optimum Pr 6 O 11 loading of 14.8 wt% reaches 1.61 A cm –2 at 1.5 V, more than double that of the SFM cathode (0.76 A cm –2 ) under the same operating conditions. X-ray photoelectron spectroscopy (XPS) characterization and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis indicate that the adsorption ability of CO 2 on the SFM cathode has been significantly improved by the formation of Pr 6 O 11 . Temperature-programmed desorption (TPD) of CO 2 measurements further manifest that a 14.8 wt% Pr 6 O 11 -SFM cathode has better CO desorption capacity. In addition, polarization resistance of the SFM cathode has significantly decreased with the addition of Pr 6 O 11 . Three-electrode measurement was used to analyze the improved electrode kinetics. Finally, these results demonstrate that the formation of Pr 6 O 11 in the SFM cathode through infiltration is a promising approach for increasing CO 2 RR activity for CO 2 -SOECs.

03 NATURAL GAS↗
DOE OSTI2020

Materials Data on Pr(Al2Cu)4 by Materials Project

Pr(CuAl2)4 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to eight equivalent Cu and twelve Al atoms. All Pr–Cu bond lengths are 3.41 Å. There are four shorter (3.11 Å) and eight longer (3.27 Å) Pr–Al bond lengths. Cu is bonded to two equivalent Pr, two equivalent Cu, and eight Al atoms to form a mixture of distorted face, edge, and corner-sharing CuPr2Al8Cu2 cuboctahedra. Both Cu–Cu bond lengths are 2.60 Å. There are four shorter (2.59 Å) and four longer (2.73 Å) Cu–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to two equivalent Pr, four equivalent Cu, and six Al atoms. There are a spread of Al–Al bond distances ranging from 2.80–2.84 Å. In the second Al site, Al is bonded in a 10-coordinate geometry to one Pr, four equivalent Cu, and five Al atoms. The Al–Al bond length is 2.69 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr(FeO3)2 by Materials Project

Pr(FeO3)2 crystallizes in the orthorhombic Pmn2_1 space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to twelve O atoms. There are a spread of Pr–O bond distances ranging from 2.47–3.07 Å. Fe is bonded to six O atoms to form corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 11–17°. There are a spread of Fe–O bond distances ranging from 1.91–1.95 Å. There are four inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two equivalent Pr and two equivalent Fe atoms. In the second O site, O is bonded in a 3-coordinate geometry to two equivalent Pr and two equivalent Fe atoms. In the third O site, O is bonded in a distorted rectangular see-saw-like geometry to two equivalent Pr and two equivalent Fe atoms. In the fourth O site, O is bonded in a 4-coordinate geometry to two equivalent Pr and two equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr(Re2Si)2 by Materials Project

Pr(Re2Si)2 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to eight Re and eight equivalent Si atoms. There are four shorter (3.37 Å) and four longer (3.47 Å) Pr–Re bond lengths. All Pr–Si bond lengths are 3.20 Å. There are two inequivalent Re sites. In the first Re site, Re is bonded in a 12-coordinate geometry to two equivalent Pr, eight Re, and two equivalent Si atoms. There are a spread of Re–Re bond distances ranging from 2.62–2.94 Å. Both Re–Si bond lengths are 2.52 Å. In the second Re site, Re is bonded to two equivalent Pr, eight Re, and two equivalent Si atoms to form a mixture of distorted edge, face, and corner-sharing RePr2Re8Si2 cuboctahedra. Both Re–Re bond lengths are 2.58 Å. Both Re–Si bond lengths are 2.56 Å. Si is bonded in a 9-coordinate geometry to four equivalent Pr, four Re, and one Si atom. The Si–Si bond length is 2.52 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Improved 140 Nd Production for the 140 Nd/ 140 Pr In Vivo Generator through Target Recycling and Radiochemical Optimization

Theranostic strategies that utilize f-block therapeutic radionuclides, including 161 Tb, 177 Lu, 225 Ac, and 227 Th, suffer from a shortage of positron emission tomography (PET) imaging counterparts in the same chemical space and often rely on 68 Ga as a surrogate. The 140 Nd/ 140 Pr in vivo PET generator, which belongs to the f-block, may address this issue and can be produced via the 141 Pr(p,2n) 140 Nd production route by using medium-energy cyclotrons. However, impurities in the target material, including stable Nd, and the inherent difficulty of adjacent lanthanide separations limit the achievable radionuclidic and chemical purity of 140 Nd. In this work, we address these challenges through the purification and recycling of praseodymium target material and optimization of Nd/Pr separation. The resulting purified 140Nd was evaluated using DOTA and Macropa chelators via radiolabeling and in vitro stability studies. A target material purification and recycling method was developed for the monoisotopic 141 Pr starting material to remove stable Nd impurities, yielding 90.3 ± 4.7% (n = 3) recovery. The purified 141 Pr was isolated as Pr 6 O 11 and irradiated with 24 MeV protons (20.07 MeV at the target surface) at 20 μA for 4 h, which produced 1417.0 ± 83.4 MBq (38.3 ± 2.2 mCi) of 140 Nd at the end of bombardment (EOB). The produced 140 Nd was purified through an optimized DGA normal method to recover 71.6 ± 6.3% pure 140 Nd. The amount of stable Nd reduced progressively in each target purification cycle from >340 ppm without purification to <250 ppb after three cycles, while other measured metallic impurities were below 30 ppb. This improvement in target purity was reflected in the direct increase of apparent molar activity (AMA), when purified 140 Nd was evaluated with DOTA and Macropa chelators. AMA of [ 140 Nd]Nd-DOTA and [ 140 Nd]Nd-Macropa increased from 70.3 MBq/μmol (1.9 mCi/μmol) and 74 MBq/μmol (2.0 mCi/μmol) to 8025.3 MBq/μmol (216.9 mCi/μmol) and 8473.0 MBq/μmol (229.0 mCi/μmol), respectively, after the third target purification cycle. Further evaluation of chelator-labeled 140 Nd showed that [ 140 Nd]Nd-DOTA was stable in phosphate-buffered saline (PBS), saline, human serum, and mouse serum, whereas [140Nd]Nd-Macropa was stable in all except human serum. This work established a practical methodological advance for the production of 140 Nd/ 140 Pr in vivo PET generators, combining optimized target recycling and radiochemical separation to enable scaled-up and high-molar activity 140 Nd suitable for preclinical imaging. These advances support broader development of 140 Nd/ 140 Pr as a robust PET analogue, especially for f-block therapeutics.

Irradiation↗
DOE OSTI2025

Production and radiochemistry of the in vivo PET generator 140 Nd/ 140 Pr as an imaging surrogate for F-block therapeutic radionuclides

Theranostics, a combined approach of diagnostics and therapeutics, often employs F-block therapeutic radionuclides including 225 Ac, 177 Lu, and 161 Tb. While there is a lack of F-block PET imaging radionuclides, the in vivo PET generator pair 140 Nd/ 140 Pr can act as a theranostic imaging counterpart to the F-block therapeutic radionuclides. In this study, we explored the production and separation of high purity 140 Nd via the 141 Pr(p,2n) 140 Nd reaction route. Monoisotopic 141 Pr targets irradiated with 20 MeV protons for 10 min with 10 µA beam current yielded 21.45 ± 0.82 MBq (580 ± 22 µCi) of 140 Nd. A two-step separation method was developed for the purification of 140 Nd from the 141 Pr target material. Recoveries of 27.4 ± 2.1% 140Nd were obtained upon separation with < 20 ppb of 141 Pr target material in the final product. Radiolabeling of Macropa and DOTA chelators with 140 Nd resulted in [ 140 Nd]Nd-Macropa with a molar activity of 74.0 MBq/µmol (2.0 mCi/µmol) and [ 140 Nd]Nd-DOTA with a molar activity of 70.3 MBq/µmol (1.9 mCi/µmol). An imaging study with a phantom indicated the PET spatial resolution of 140 Nd/ 140 Pr was distinguishable down to 2.4 mm. This study sets the stage for the 140 Nd/ 140 Pr in vivo PET generator to be explored in radiopharmaceutical applications.

F-block↗
DOE OSTI2020

Materials Data on Pr(AlZn)2 by Materials Project

Pr(ZnAl)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pr is bonded in a 8-coordinate geometry to eight equivalent Zn and eight equivalent Al atoms. All Pr–Zn bond lengths are 3.23 Å. All Pr–Al bond lengths are 3.47 Å. Zn is bonded in a 9-coordinate geometry to four equivalent Pr, one Zn, and four equivalent Al atoms. The Zn–Zn bond length is 2.47 Å. All Zn–Al bond lengths are 2.60 Å. Al is bonded to four equivalent Pr and four equivalent Zn atoms to form a mixture of distorted corner, edge, and face-sharing AlPr4Zn4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr(CoGe)2 by Materials Project

Pr(CoGe)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pr is bonded in a 8-coordinate geometry to eight equivalent Co and eight equivalent Ge atoms. All Pr–Co bond lengths are 3.29 Å. All Pr–Ge bond lengths are 3.17 Å. Co is bonded to four equivalent Pr and four equivalent Ge atoms to form a mixture of distorted edge, face, and corner-sharing CoPr4Ge4 tetrahedra. All Co–Ge bond lengths are 2.36 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Pr, four equivalent Co, and one Ge atom. The Ge–Ge bond length is 2.76 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr(NiSn)2 by Materials Project

Pr(NiSn)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pr is bonded in a 8-coordinate geometry to eight equivalent Ni and eight equivalent Sn atoms. All Pr–Ni bond lengths are 3.45 Å. All Pr–Sn bond lengths are 3.45 Å. Ni is bonded in a 4-coordinate geometry to four equivalent Pr and four equivalent Sn atoms. All Ni–Sn bond lengths are 2.52 Å. Sn is bonded in a 9-coordinate geometry to four equivalent Pr, four equivalent Ni, and one Sn atom. The Sn–Sn bond length is 2.87 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr(AsPd)2 by Materials Project

Pr(PdAs)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pr is bonded in a 8-coordinate geometry to eight equivalent Pd and eight equivalent As atoms. All Pr–Pd bond lengths are 3.40 Å. All Pr–As bond lengths are 3.32 Å. Pd is bonded in a 12-coordinate geometry to four equivalent Pr and four equivalent As atoms. All Pd–As bond lengths are 2.56 Å. As is bonded in a 9-coordinate geometry to four equivalent Pr, four equivalent Pd, and one As atom. The As–As bond length is 2.54 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr(BRu)2 by Materials Project

Pr(RuB)2 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Pr is bonded in a 10-coordinate geometry to four equivalent Ru and six equivalent B atoms. All Pr–Ru bond lengths are 3.04 Å. There are two shorter (2.93 Å) and four longer (3.07 Å) Pr–B bond lengths. Ru is bonded in a 4-coordinate geometry to two equivalent Pr and four equivalent B atoms. There are two shorter (2.09 Å) and two longer (2.16 Å) Ru–B bond lengths. B is bonded in a 7-coordinate geometry to three equivalent Pr and four equivalent Ru atoms.

36 MATERIALS SCIENCE↗