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DOE OSTI2020

Materials Data on Ca5(OsN3)2 by Materials Project

Ca5(OsN3)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six N3- atoms to form distorted CaN6 pentagonal pyramids that share corners with four equivalent CaN6 octahedra, corners with two equivalent CaN5 trigonal bipyramids, edges with four equivalent CaN6 octahedra, and edges with four equivalent CaN5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 8–29°. There are a spread of Ca–N bond distances ranging from 2.39–2.73 Å. In the second Ca2+ site, Ca2+ is bonded to six N3- atoms to form distorted CaN6 octahedra that share corners with two equivalent CaN6 pentagonal pyramids, corners with six equivalent CaN5 trigonal bipyramids, edges with three equivalent CaN6 octahedra, edges with two equivalent CaN6 pentagonal pyramids, and edges with two equivalent CaN5 trigonal bipyramids. There are a spread of Ca–N bond distances ranging from 2.53–2.84 Å. In the third Ca2+ site, Ca2+ is bonded to five N3- atoms to form distorted CaN5 trigonal bipyramids that share corners with six equivalent CaN6 octahedra, a cornercorner with one CaN6 pentagonal pyramid, corners with two equivalent CaN5 trigonal bipyramids, edges with two equivalent CaN6 octahedra, edges with two equivalent CaN6 pentagonal pyramids, and an edgeedge with one CaN5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 6–79°. There are a spread of Ca–N bond distances ranging from 2.35–2.68 Å. Os4+ is bonded in a distorted trigonal planar geometry to four N3- atoms. There are a spread of Os–N bond distances ranging from 1.87–2.71 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a 2-coordinate geometry to four Ca2+ and two equivalent Os4+ atoms. In the second N3- site, N3- is bonded to five Ca2+ and one Os4+ atom to form a mixture of distorted corner, edge, and face-sharing NCa5Os octahedra. The corner-sharing octahedra tilt angles range from 12–73°. In the third N3- site, N3- is bonded to five Ca2+ and one Os4+ atom to form a mixture of distorted corner and edge-sharing NCa5Os octahedra. The corner-sharing octahedra tilt angles range from 12–73°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Li5OsO6 by Materials Project

Li5OsO6 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with six LiO6 octahedra, edges with three equivalent OsO6 octahedra, and edges with nine LiO6 octahedra. The corner-sharing octahedra tilt angles range from 8–12°. There are a spread of Li–O bond distances ranging from 2.08–2.10 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent OsO6 octahedra, corners with four equivalent LiO6 octahedra, edges with two equivalent OsO6 octahedra, and edges with ten LiO6 octahedra. The corner-sharing octahedra tilt angles range from 2–12°. There are a spread of Li–O bond distances ranging from 2.07–2.19 Å. In the third Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent OsO6 octahedra, corners with four equivalent LiO6 octahedra, edges with two equivalent OsO6 octahedra, and edges with ten LiO6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are four shorter (2.07 Å) and two longer (2.24 Å) Li–O bond lengths. Os7+ is bonded to six O2- atoms to form OsO6 octahedra that share corners with six LiO6 octahedra and edges with twelve LiO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There is two shorter (1.89 Å) and four longer (1.93 Å) Os–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to five Li1+ and one Os7+ atom to form a mixture of corner and edge-sharing OLi5Os octahedra. The corner-sharing octahedra tilt angles range from 0–14°. In the second O2- site, O2- is bonded to five Li1+ and one Os7+ atom to form a mixture of corner and edge-sharing OLi5Os octahedra. The corner-sharing octahedra tilt angles range from 0–7°.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Prophylactic Cranial Irradiation Reduces Brain Metastases and Improves Overall Survival in High-Risk Metastatic Non-Small Cell Lung Cancer Patients: A Randomized phase 2 Study (PRoT-BM trial)

To date, studies regarding the use of prophylactic cranial irradiation (PCI) versus standard of care (SoC) for patients with non-small cell lung cancer (NSCLC) have not shown a significant effect in terms of overall survival (OS). Additionally, the effect of PCI among high-risk patients has been scarcely studied. The objective of this randomized phase 2 study was to evaluate the role of PCI in a population of patients at high risk for development of brain metastases (BM).

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2021

Revisions of ORNL 188 W Process Based on Nonradiological Experiments

Tungsten-188 is in widespread use in the 188 W(t 1/2 = 69 d)/ 188 Re(t 1/2 =16.9 h) biomedical generator. Oak Ridge National Laboratory (ORNL) has been providing this product to the world since 1999. At ORNL, 188 W is produced via irradiation in ORNL’s High Flux Isotope Reactor (HFIR). Enriched 186 W targets in the form of sintered metallic pellets or rings achieve a compact loading in the irradiation vessel, providing a high yield per unit target. The enrichment of the target is >90% 186 W and this isotope undergoes double neutron capture to produce the desired 188W product. While 188 W is produced by neutron bombardment, 191 Os(t 1/2 = 15.4 d) is simultaneously produced as a byproduct requiring separation from 188 W by post irradiation treatment. In the current processing pathway, the irradiated W metal pellets or rings are first converted into an oxide form of WO 3 by heating the irradiated W metal target at 750°C in a quartz reaction vessel inside a vertical furnace under a constant flow of air. During heating, W metal reacts with oxygen in the air to produce WO 3 , which is soluble in 6 M NaOH for later purification process. This oxidation process also converts 188 Os (the decay daughter of 188 W) and 191 Os (the irradiation produced byproduct) into OsO 4 , a highly volatile and toxic gas. The gaseous effluents driven from the quartz reaction vessel are passed through a scrubbing array to remove OsO 4 before the air is discharged from the process. This heterogeneous oxidation method simultaneously achieves two goals: 1). converting metal target to a soluble oxide form and 2). separating volatile OsO 4 away from the solid WO 3 product, although harmful 191 OsO 4 is unfavorable but being taken care of by the down road scrubbing array. In the past twenty years the existing OsO 4 scrubbing array served well in preventing OsO 4 from being released into the environment, until July of 2020 when a minor amount of 191 Os was found to have been released into the environment which resulted in a standby of building 4501 from July 2020 to February 2021.Since October 20 of 2020 a team of researchers from groups of RSTD and NEFD were organized to work for the following tasks: (1) Fully understand the root causes of the July incident of 191 Os release and create a redesigned 191 Os scrubbing array to eliminate the possibility of 191 Os release in future 188 W processes; (2) In Phase-1 tests, select a correct air (O 2 ) flow rate in 188 W process, that provides sufficient oxygen for the oxidation of tungsten metal, while still allowing sufficient resonance time for 191 Os removal by the scrubbers; (3) In Phase-2 tests, confirm the efficiency of the redesigned scrubbing array to absorb excessive amount of non-rad OsO 4 (generated from Os metal powder) at the selected air flow; (4) In Phase-3 tests, simulate the hot cell 188 W process by heating pressed non-rad W-Os pellets in a quartz vessel of new design and the new array under operation parameters selected in Phase-1 and -2; (5) Complete a new operation procedure for 188 W process in hot cell and a TM report as a summary of the Os Mitigation Project. This TM report summarizes the investigation on root causes from technical aspects in July 191 Os release and the correspondent improvement towards the redesigned 191 Os scrubbing system. The report presents the efforts made on selection of optimal operational parameter with the new scrubbing array and the quartz vessel of new design, based on experiment data obtained in Phase-1, -2 and -3 tests. Further renovations for 188 W process and additional improvement of W target treatment will also be discussed.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2020

Materials Data on LaOsN3 by Materials Project

LaOsN3 crystallizes in the monoclinic P2_1/m space group. The structure is one-dimensional and consists of two LaOsN3 ribbons oriented in the (1, 0, 0) direction. La3+ is bonded in a 1-coordinate geometry to one N3- atom. The La–N bond length is 2.47 Å. Os6+ is bonded in a T-shaped geometry to three N3- atoms. There are a spread of Os–N bond distances ranging from 1.91–2.02 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a 2-coordinate geometry to one Os6+ and one N3- atom. The N–N bond length is 1.24 Å. In the second N3- site, N3- is bonded in a distorted linear geometry to two equivalent Os6+ atoms. In the third N3- site, N3- is bonded in a 2-coordinate geometry to one La3+ and one N3- atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on KOsN(Cl2O)2 by Materials Project

KOsN(OCl2)2 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to three O2- and four Cl1- atoms. There are a spread of K–O bond distances ranging from 2.75–3.08 Å. There are two shorter (3.39 Å) and two longer (3.67 Å) K–Cl bond lengths. Os2+ is bonded in a distorted octahedral geometry to one N5+, one O2-, and four Cl1- atoms. The Os–N bond length is 1.69 Å. The Os–O bond length is 2.01 Å. There are two shorter (2.31 Å) and two longer (2.39 Å) Os–Cl bond lengths. N5+ is bonded in a single-bond geometry to one Os2+ atom. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and one Os2+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+ and two equivalent Cl1- atoms. Both O–Cl bond lengths are 2.44 Å. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one K1+ and one Os2+ atom. In the second Cl1- site, Cl1- is bonded in a 2-coordinate geometry to one K1+, one Os2+, and one O2- atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on H12OsSN4O7 by Materials Project

(OsH12(N2O)2)2(SO4)2O2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four sulfuric acid molecules, four water molecules, and four OsH12(N2O)2 clusters. In two of the OsH12(N2O)2 clusters, Os8+ is bonded in an octahedral geometry to four N1- and two equivalent O2- atoms. All Os–N bond lengths are 2.14 Å. Both Os–O bond lengths are 1.75 Å. There are two inequivalent N1- sites. In the first N1- site, N1- is bonded in a trigonal non-coplanar geometry to one Os8+ and three H1+ atoms. There is one shorter (1.03 Å) and two longer (1.04 Å) N–H bond length. In the second N1- site, N1- is bonded in a trigonal non-coplanar geometry to one Os8+ and three H1+ atoms. There is two shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. O2- is bonded in a single-bond geometry to one Os8+ atom. In two of the OsH12(N2O)2 clusters, Os8+ is bonded in an octahedral geometry to four N1- and two equivalent O2- atoms. All Os–N bond lengths are 2.14 Å. Both Os–O bond lengths are 1.75 Å. There are two inequivalent N1- sites. In the first N1- site, N1- is bonded in a trigonal non-coplanar geometry to one Os8+ and three H1+ atoms. There is two shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. In the second N1- site, N1- is bonded in a trigonal non-coplanar geometry to one Os8+ and three H1+ atoms. There is two shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. O2- is bonded in a single-bond geometry to one Os8+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Surfactant-free syntheses and pair distribution function analysis of osmium nanoparticles

A surfactant-free synthesis of precious metal nanoparticles (NPs) performed in alkaline low-boiling-point solvents has been recently reported. Monoalcohols are here investigated as solvents and reducing agents to obtain colloidal Os nanoparticles by using low-temperature (<100 °C) surfactant-free syntheses. The effect of the precursor (OsCl 3 or H 2 OsCl 6 ), precursor concentration (up to 100 mM), solvent (methanol or ethanol), presence or absence of a base (NaOH), and addition of water (0 to 100 vol %) on the resulting nanomaterials is discussed. It is found that no base is required to obtain Os nanoparticles as opposed to the case of Pt or Ir NPs. The robustness of the synthesis for a precursor concentration up to 100 mM allows for the performance of X-ray total scattering with pair distribution function (PDF) analysis, which shows that 1–2 nm hexagonal close packed (hcp) NPs are formed from chain-like [OsO x Cl y ] complexes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Fleetite, Cu 2 RhIrSb 2 , a New Species of Platinum-Group Mineral from the Miass Placer Zone, Southern Urals, Russia

Fleetite, Cu 2 RhIrSb 2 , a new species of platinum-group mineral (PGM), was discovered intergrown with an Os–Ir–Ru alloy in the Miass Placer Zone (Au–PGE), southern Urals, Russia. A single grain 50 μm across was found. Osmium, ruthenium, and iridium are the main associated minerals; also present are Pt–Fe alloys, laurite, Sb-rich irarsite, Rh-rich tolovkite, kashinite, anduoite, ferronickelplatinum, heazlewoodite, PGE-bearing pentlandite and digenite, as well as micrometric inclusions of forsterite (Fo 93.7 ), chromite–magnesiochromite, and Mg-rich edenite. In reflected light, fleetite is light gray; it is opaque, isotropic, non-pleochroic, and non-bireflectant. We report reflectance values measured in air. A mean of seven point-analyses (wavelength-dispersive spectrometry) gave Cu 13.93, Ni 8.60, Fe 0.10, Ir 28.07, Rh 7.91, Ru 1.96, Sb 39.28, total 99.85 wt.%, corresponding to (Cu 1.41 Ni 0.58 Fe 0.01 ) Σ2.00 (Rh 0.49 Ni 0.36 Ru 0.12 ) Σ0.97 Ir 0.95 Sb 2.08 on the basis of six atoms per formula unit, taking into account the structural results. The calculated density is 10.83 g/cm 3 . Single-crystal X-ray studies show that fleetite is cubic, space group Fdm (#227), a = 11.6682(8) Å, V = 1588.59(19) Å 3 , and Z = 16. A least-squares refinement of X-ray powder-diffraction data gave a = 11.6575(5) Å and V = 1584.22(19) Å 3 . The strongest five reflections in the powder pattern [d in Å(I)(hkl)] are: 6.70(75)(111), 4.13(100)(220), 3.52(30)(311), 2.380(50)(422), 2.064(40)(440). Results of synchrotron micro-Laue diffraction experiments are consistent [a = 11.66(2) Å]. The crystal structure of fleetite was solved and refined to R = 0.0340 based upon 153 reflections with F o > 4σ(F o ). It is isotypic with Pd 11 Bi 2 Se 2 and best described as intermetallic, with all metal atoms in 12-fold coordination. Fleetite and other late exotic phases were formed by reaction of the associated alloy phases with a fluid phase enriched in Sb, As, and S in circulation in the cooling ophiolite source-rock. The mineral is named after Michael E. Fleet (1938–2017) in recognition of his significant contributions to the Earth Sciences.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Ferrotorryweiserite, Rh 5 Fe 10 S 16 , a New Mineral Species from the Sisim Placer Zone, Eastern Sayans, Russia, and the Torryweiserite–Ferrotorryweiserite Series

Ferrotorryweiserite, Rh 5 Fe 10 S 16 , occurs as small grains (≤20 µm) among droplet-like inclusions (up to 50 μm in diameter) of platinum-group minerals (PGM), in association with oberthürite or Rh-bearing pentlandite, laurite, and a Pt-Pd-Fe alloy (likely isoferroplatinum and Fe-Pd-enriched platinum), hosted by placer grains of Os-Ir alloy (≤0.5 mm) in the River Ko deposit. The latter is a part of the Sisim placer zone, which is likely derived from ultramafic units of the Lysanskiy layered complex, southern Krasnoyarskiy kray, Russia. The mineral is opaque, gray to brownish gray in reflected light, very weakly bireflectant, not pleochroic to weakly pleochroic (grayish to light brown tints), and weakly anisotropic. The calculated density is 5.93 g·cm –3 . Mean results (and ranges) of four WDS analyses are: Ir 18.68 (15.55–21.96), Rh 18.34 (16.32–20.32), Pt 0.64 (0.19–1.14), Ru 0.03 (0.00–0.13), Os 0.07 (0.02–0.17), Fe 14.14 (13.63–14.64), Ni 13.63 (12.58–14.66), Cu 4.97 (3.42–6.41), Co 0.09 (0.07–0.11), S 29.06 (28.48–29.44), and total 99.66 wt.%. They correspond to the following formula calculated for a total of 31 atoms per formula unit: (Rh 3.16 Ir 1.72 Pt 0.06 Ru 0.01 Os 0.01 ) Σ 4.95 (Fe 4.48 Ni 4.11 Cu 1.38 Co 0.03 ) Σ10.00 S 16.05 . The results of synchrotron micro-Laue diffraction studies indicate that ferrotorryweiserite is trigonal; its probable space group is $R\bar{3}m$ (#166) based on its Ni-analog, torryweiserite. The unit-cell parameters refined from 177 reflections are a = 7.069 (2) Å, c = 34.286 (11) Å, V = 1484 (1) Å 3 , and Z = 3. The c:a ratio is 4.8502. The strongest eight peaks in the X-ray diffraction pattern derived from results of micro-Laue diffraction study [d in Å(hkil)(I)] are 2.7950 ($20\bar{2}5$) (100); 5.7143 (0006) (60); 1.7671 ($22\bar{4}0$) (44.4); 3.0486 ($20\bar{2}1$) (39.4); 5.7650 ($10\bar{1}2$) (38.6); 2.5956 ($20\bar{2}7$) (37.8); 3.0058 ($11\bar{2}6$) (36.5); and 1.5029 ($4\bar{2}\bar{2}12$) (35.3). Ferrotorryweiserite and the associated PGM crystallized from microvolumes of residual melt at late stages of crystallization of grains of Os- and Ir-dominant alloys occurred in lode zones of chromitites of the Lysanskiy layered complex. In a particular case, the residual melt is disposed peripherally around a core containing a disequilibrium association of magnesian olivine (Fo 72.9–75.6 ) and albite (Ab 81.6–86.4 ), with the development of skeletal crystals of titaniferous augite: Wo 40.8–43.2 En 26.5–29.3 Fs 20.3–22.6 Aeg 6.9–9.5 (2.82–3.12 wt.% TiO 2 ). Ferrotorryweiserite represents the Fe-dominant analog of torryweiserite. We also report occurrences of ferrotorryweiserite in the Marathon deposit, Coldwell Complex, Ontario, Canada, and infer the existence of the torryweiserite–ferrotorryweiserite solid solution in other deposits and complexes.

58 GEOSCIENCES↗

DOE OSTI2020

Materials Data on K3NaOs2O9 by Materials Project

K3NaOs2O9 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to twelve O2- atoms to form distorted KO12 cuboctahedra that share corners with twelve KO12 cuboctahedra, faces with six equivalent KO12 cuboctahedra, faces with two equivalent NaO6 octahedra, and faces with six equivalent OsO6 octahedra. There are six shorter (3.00 Å) and six longer (3.05 Å) K–O bond lengths. In the second K1+ site, K1+ is bonded to twelve O2- atoms to form distorted KO12 cuboctahedra that share corners with nine KO12 cuboctahedra, corners with three equivalent OsO6 octahedra, faces with seven KO12 cuboctahedra, faces with three equivalent NaO6 octahedra, and faces with four equivalent OsO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are a spread of K–O bond distances ranging from 2.92–3.31 Å. Na1+ is bonded to six equivalent O2- atoms to form NaO6 octahedra that share corners with six equivalent OsO6 octahedra and faces with eight KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 6°. All Na–O bond lengths are 2.32 Å. Os7+ is bonded to six O2- atoms to form distorted OsO6 octahedra that share corners with three equivalent KO12 cuboctahedra, corners with three equivalent NaO6 octahedra, faces with seven KO12 cuboctahedra, and a faceface with one OsO6 octahedra. The corner-sharing octahedral tilt angles are 6°. There is three shorter (1.81 Å) and three longer (2.03 Å) Os–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four K1+ and two equivalent Os7+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Os7+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sc13Os3Br16 by Materials Project

Sc13Os3Br16 crystallizes in the orthorhombic Pnnm space group. The structure is two-dimensional and consists of two Sc13Os3Br16 sheets oriented in the (0, 0, 1) direction. there are five inequivalent Sc sites. In the first Sc site, Sc is bonded in a 6-coordinate geometry to two Os and four Br atoms. There are one shorter (2.69 Å) and one longer (2.80 Å) Sc–Os bond lengths. There are a spread of Sc–Br bond distances ranging from 2.70–3.31 Å. In the second Sc site, Sc is bonded in a 6-coordinate geometry to two Os and four Br atoms. There are one shorter (2.64 Å) and one longer (2.77 Å) Sc–Os bond lengths. There are a spread of Sc–Br bond distances ranging from 2.80–3.31 Å. In the third Sc site, Sc is bonded to two equivalent Os and four Br atoms to form distorted ScOs2Br4 octahedra that share corners with two equivalent ScBr6 octahedra, an edgeedge with one ScOs2Br4 octahedra, and faces with two equivalent ScOs2Br4 pentagonal pyramids. The corner-sharing octahedral tilt angles are 29°. Both Sc–Os bond lengths are 2.68 Å. There are a spread of Sc–Br bond distances ranging from 2.75–3.02 Å. In the fourth Sc site, Sc is bonded to two equivalent Os and four Br atoms to form a mixture of distorted edge and face-sharing ScOs2Br4 pentagonal pyramids. Both Sc–Os bond lengths are 2.76 Å. There are a spread of Sc–Br bond distances ranging from 2.80–2.84 Å. In the fifth Sc site, Sc is bonded to six Br atoms to form corner-sharing ScBr6 octahedra. The corner-sharing octahedral tilt angles are 29°. There are two shorter (2.69 Å) and four longer (2.73 Å) Sc–Br bond lengths. There are two inequivalent Os sites. In the first Os site, Os is bonded in a 8-coordinate geometry to eight Sc atoms. In the second Os site, Os is bonded in a body-centered cubic geometry to eight Sc atoms. There are six inequivalent Br sites. In the first Br site, Br is bonded in a distorted T-shaped geometry to three Sc atoms. In the second Br site, Br is bonded in a 4-coordinate geometry to four Sc atoms. In the third Br site, Br is bonded in a 3-coordinate geometry to three Sc atoms. In the fourth Br site, Br is bonded in a 4-coordinate geometry to four Sc atoms. In the fifth Br site, Br is bonded in a 2-coordinate geometry to two equivalent Sc atoms. In the sixth Br site, Br is bonded in a 2-coordinate geometry to four Sc atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on OsPbO3 by Materials Project

OsPbO3 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Os4+ is bonded to six equivalent O2- atoms to form corner-sharing OsO6 octahedra. The corner-sharing octahedral tilt angles are 43°. All Os–O bond lengths are 1.98 Å. Pb2+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All Pb–O bond lengths are 2.64 Å. O2- is bonded in a 2-coordinate geometry to two equivalent Os4+ and two equivalent Pb2+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sr2MgOsO6 by Materials Project

Sr2MgOsO6 is (Cubic) Perovskite-derived structured and crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with twelve equivalent SrO12 cuboctahedra, faces with six equivalent SrO12 cuboctahedra, faces with four equivalent MgO6 octahedra, and faces with four equivalent OsO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.70–2.94 Å. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent OsO6 octahedra and faces with eight equivalent SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–10°. All Mg–O bond lengths are 2.05 Å. Os6+ is bonded to six O2- atoms to form OsO6 octahedra that share corners with six equivalent MgO6 octahedra and faces with eight equivalent SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–10°. There is four shorter (1.93 Å) and two longer (1.94 Å) Os–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Sr2+, one Mg2+, and one Os6+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four equivalent Sr2+, one Mg2+, and one Os6+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Amorphizing noble metal chalcogenide catalysts at the single-layer limit towards hydrogen production

Rational design of noble metal catalysts with the potential to leverage efficiency is vital for industrial applications. Such an ultimate atom-utilization efficiency can be achieved when all noble metal atoms exclusively contribute to catalysis. In this work, we demonstrate the fabrication of a wafer-size amorphous PtSex film on a SiO 2 substate via a low-temperature amorphization strategy, which offers single-atom-layer Pt catalysts with high atom-utilization efficiency (~26 wt%). This amorphous PtSex (1.2 < x < 1.3) behaves as a fully activated surface, accessible to catalytic reactions, and features a nearly 100% current density relative to a pure Pt surface and reliable production of sustained high-flux hydrogen over a 2 inch wafer as a proof-of-concept. Furthermore, an electrolyser is demonstrated to generate a high current density of 1,000 mA cm –2 . Such an amorphization strategy is potentially extendable to other noble metals, including the Pd, Ir, Os, Rh and Ru elements, demonstrating the universality of single-atom-layer catalysts.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Pavilion 2 Feature Additions [Slides]

Pavilion 2 is a critical component of system testing for LANL HPC systems. Pavilion 2 is system independent, which allows for the creation of a large suite of generalized tests than can be applied to multiple systems. These additions to Pavilion 2 improve our ability to test systems and diagnose issues. With such a large suite, running the proper tests when diagnosing and fixing a system can be difficult, as well as locating old tests for reference. Test configurations may contain several permutations of a test, not all of which may apply to a given system. The ability to run sets of test permutations lets the tester focus on specific parts of the test without having to edit the test configurations or run extraneous tests. The addition of the filter argument improves the ability to find test results based on test attributes, including past tests. Pavilion 2's system independence is largely based on various layers of configuration files. Configuration files for the host, test, and modes exist to allow generalized testing. The operating system configuration layer can provide helpful OS defaults to a test. Survey, a collection and reporting tool, can help us gauge the performance of a system as well as diagnose issues. The addition of a Survey mode in Pavilion 2 makes running tests with Survey very straightforward. The Survey results are combined with Pavilion 2's test results to make it easy to access.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2023

Pavilion 2 Feature Additions [Slides]

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2020

Materials Data on YbB4Os by Materials Project

YbOsB4 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Yb2+ is bonded in a 2-coordinate geometry to four equivalent Os2- and fourteen B atoms. There are a spread of Yb–Os bond distances ranging from 3.02–3.10 Å. There are a spread of Yb–B bond distances ranging from 2.62–2.76 Å. Os2- is bonded in a 10-coordinate geometry to four equivalent Yb2+, one Os2-, and ten B atoms. The Os–Os bond length is 2.60 Å. There are a spread of Os–B bond distances ranging from 2.27–2.37 Å. There are four inequivalent B sites. In the first B site, B is bonded in a 3-coordinate geometry to four equivalent Yb2+, two equivalent Os2-, and three B atoms. There are a spread of B–B bond distances ranging from 1.75–1.85 Å. In the second B site, B is bonded in a 5-coordinate geometry to four equivalent Yb2+, two equivalent Os2-, and three B atoms. The B–B bond length is 1.84 Å. In the third B site, B is bonded in a 3-coordinate geometry to four equivalent Yb2+, two equivalent Os2-, and three B atoms. There is one shorter (1.74 Å) and one longer (1.77 Å) B–B bond length. In the fourth B site, B is bonded in a 9-coordinate geometry to two equivalent Yb2+, four equivalent Os2-, and three B atoms. The B–B bond length is 1.74 Å.

36 MATERIALS SCIENCE↗