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At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Eu3Zr by Materials Project

Eu3Zr is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Eu is bonded to eight equivalent Eu and four equivalent Zr atoms to form EuEu8Zr4 cuboctahedra that share corners with twelve equivalent EuEu8Zr4 cuboctahedra, edges with eight equivalent ZrEu12 cuboctahedra, edges with sixteen equivalent EuEu8Zr4 cuboctahedra, faces with four equivalent ZrEu12 cuboctahedra, and faces with fourteen equivalent EuEu8Zr4 cuboctahedra. All Eu–Eu bond lengths are 3.70 Å. All Eu–Zr bond lengths are 3.70 Å. Zr is bonded to twelve equivalent Eu atoms to form ZrEu12 cuboctahedra that share corners with twelve equivalent ZrEu12 cuboctahedra, edges with twenty-four equivalent EuEu8Zr4 cuboctahedra, faces with six equivalent ZrEu12 cuboctahedra, and faces with twelve equivalent EuEu8Zr4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TbEu3 by Materials Project

TbEu3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Tb is bonded to twelve equivalent Eu atoms to form TbEu12 cuboctahedra that share corners with six equivalent TbEu12 cuboctahedra, corners with twelve equivalent EuTb4Eu8 cuboctahedra, edges with eighteen equivalent EuTb4Eu8 cuboctahedra, faces with eight equivalent TbEu12 cuboctahedra, and faces with twelve equivalent EuTb4Eu8 cuboctahedra. There are six shorter (3.79 Å) and six longer (3.83 Å) Tb–Eu bond lengths. Eu is bonded to four equivalent Tb and eight equivalent Eu atoms to form EuTb4Eu8 cuboctahedra that share corners with four equivalent TbEu12 cuboctahedra, corners with fourteen equivalent EuTb4Eu8 cuboctahedra, edges with six equivalent TbEu12 cuboctahedra, edges with twelve equivalent EuTb4Eu8 cuboctahedra, faces with four equivalent TbEu12 cuboctahedra, and faces with sixteen equivalent EuTb4Eu8 cuboctahedra. There are a spread of Eu–Eu bond distances ranging from 3.76–3.91 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu3Cr by Materials Project

Eu3Cr is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Eu is bonded to eight equivalent Eu and four equivalent Cr atoms to form distorted EuEu8Cr4 cuboctahedra that share corners with four equivalent CrEu12 cuboctahedra, corners with fourteen equivalent EuEu8Cr4 cuboctahedra, edges with six equivalent CrEu12 cuboctahedra, edges with twelve equivalent EuEu8Cr4 cuboctahedra, faces with four equivalent CrEu12 cuboctahedra, and faces with sixteen equivalent EuEu8Cr4 cuboctahedra. There are a spread of Eu–Eu bond distances ranging from 3.61–3.88 Å. There are two shorter (3.61 Å) and two longer (3.75 Å) Eu–Cr bond lengths. Cr is bonded to twelve equivalent Eu atoms to form CrEu12 cuboctahedra that share corners with six equivalent CrEu12 cuboctahedra, corners with twelve equivalent EuEu8Cr4 cuboctahedra, edges with eighteen equivalent EuEu8Cr4 cuboctahedra, faces with eight equivalent CrEu12 cuboctahedra, and faces with twelve equivalent EuEu8Cr4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu3Nb by Materials Project

Eu3Nb is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Eu is bonded to eight equivalent Eu and four equivalent Nb atoms to form distorted EuEu8Nb4 cuboctahedra that share corners with four equivalent NbEu12 cuboctahedra, corners with fourteen equivalent EuEu8Nb4 cuboctahedra, edges with six equivalent NbEu12 cuboctahedra, edges with twelve equivalent EuEu8Nb4 cuboctahedra, faces with four equivalent NbEu12 cuboctahedra, and faces with sixteen equivalent EuEu8Nb4 cuboctahedra. There are a spread of Eu–Eu bond distances ranging from 3.31–3.65 Å. There are two shorter (3.36 Å) and two longer (3.48 Å) Eu–Nb bond lengths. Nb is bonded to twelve equivalent Eu atoms to form NbEu12 cuboctahedra that share corners with six equivalent NbEu12 cuboctahedra, corners with twelve equivalent EuEu8Nb4 cuboctahedra, edges with eighteen equivalent EuEu8Nb4 cuboctahedra, faces with eight equivalent NbEu12 cuboctahedra, and faces with twelve equivalent EuEu8Nb4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuGe3Rh by Materials Project

EuRhGe3 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Eu is bonded in a 12-coordinate geometry to five equivalent Rh and twelve Ge atoms. There are four shorter (3.51 Å) and one longer (3.54 Å) Eu–Rh bond lengths. There are a spread of Eu–Ge bond distances ranging from 3.26–3.42 Å. Rh is bonded in a 5-coordinate geometry to five equivalent Eu and five Ge atoms. There are one shorter (2.42 Å) and four longer (2.46 Å) Rh–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 2-coordinate geometry to four equivalent Eu, two equivalent Rh, and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.75 Å. In the second Ge site, Ge is bonded in a distorted single-bond geometry to four equivalent Eu, one Rh, and four equivalent Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu3Ti by Materials Project

Eu3Ti is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Eu is bonded to eight equivalent Eu and four equivalent Ti atoms to form EuEu8Ti4 cuboctahedra that share corners with twelve equivalent EuEu8Ti4 cuboctahedra, edges with eight equivalent TiEu12 cuboctahedra, edges with sixteen equivalent EuEu8Ti4 cuboctahedra, faces with four equivalent TiEu12 cuboctahedra, and faces with fourteen equivalent EuEu8Ti4 cuboctahedra. All Eu–Eu bond lengths are 3.65 Å. All Eu–Ti bond lengths are 3.65 Å. Ti is bonded to twelve equivalent Eu atoms to form TiEu12 cuboctahedra that share corners with twelve equivalent TiEu12 cuboctahedra, edges with twenty-four equivalent EuEu8Ti4 cuboctahedra, faces with six equivalent TiEu12 cuboctahedra, and faces with twelve equivalent EuEu8Ti4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu3Er by Materials Project

ErEu3 is Magnesium-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Er is bonded to twelve equivalent Eu atoms to form ErEu12 cuboctahedra that share corners with six equivalent ErEu12 cuboctahedra, corners with twelve equivalent EuEu8Er4 cuboctahedra, edges with eighteen equivalent EuEu8Er4 cuboctahedra, faces with eight equivalent ErEu12 cuboctahedra, and faces with twelve equivalent EuEu8Er4 cuboctahedra. There are six shorter (3.77 Å) and six longer (3.83 Å) Er–Eu bond lengths. Eu is bonded to four equivalent Er and eight equivalent Eu atoms to form EuEu8Er4 cuboctahedra that share corners with four equivalent ErEu12 cuboctahedra, corners with fourteen equivalent EuEu8Er4 cuboctahedra, edges with six equivalent ErEu12 cuboctahedra, edges with twelve equivalent EuEu8Er4 cuboctahedra, faces with four equivalent ErEu12 cuboctahedra, and faces with sixteen equivalent EuEu8Er4 cuboctahedra. There are a spread of Eu–Eu bond distances ranging from 3.75–3.90 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbEu by Materials Project

EuYb crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Yb is bonded in a 8-coordinate geometry to four equivalent Yb and four equivalent Eu atoms. All Yb–Yb bond lengths are 3.76 Å. All Yb–Eu bond lengths are 3.74 Å. Eu is bonded in a 8-coordinate geometry to four equivalent Yb and four equivalent Eu atoms. All Eu–Eu bond lengths are 3.76 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2EuBeO5 by Materials Project

Ca2BeEuO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ca is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Ca–O bond distances ranging from 2.48–2.82 Å. Be is bonded in a tetrahedral geometry to four O atoms. There are a spread of Be–O bond distances ranging from 1.63–1.67 Å. Eu is bonded in a 7-coordinate geometry to eight O atoms. There are a spread of Eu–O bond distances ranging from 2.34–2.86 Å. There are four inequivalent O sites. In the first O site, O is bonded in a 6-coordinate geometry to four equivalent Ca and two equivalent Eu atoms. In the second O site, O is bonded in a 1-coordinate geometry to four equivalent Ca, one Be, and one Eu atom. In the third O site, O is bonded in a distorted single-bond geometry to four equivalent Ca, one Be, and one Eu atom. In the fourth O site, O is bonded in a 1-coordinate geometry to three equivalent Ca, one Be, and two equivalent Eu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiEu3 by Materials Project

LiEu3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Li is bonded to twelve equivalent Eu atoms to form LiEu12 cuboctahedra that share corners with six equivalent LiEu12 cuboctahedra, corners with twelve equivalent EuLi4Eu8 cuboctahedra, edges with eighteen equivalent EuLi4Eu8 cuboctahedra, faces with eight equivalent LiEu12 cuboctahedra, and faces with twelve equivalent EuLi4Eu8 cuboctahedra. There are six shorter (3.79 Å) and six longer (3.80 Å) Li–Eu bond lengths. Eu is bonded to four equivalent Li and eight equivalent Eu atoms to form EuLi4Eu8 cuboctahedra that share corners with four equivalent LiEu12 cuboctahedra, corners with fourteen equivalent EuLi4Eu8 cuboctahedra, edges with six equivalent LiEu12 cuboctahedra, edges with twelve equivalent EuLi4Eu8 cuboctahedra, faces with four equivalent LiEu12 cuboctahedra, and faces with sixteen equivalent EuLi4Eu8 cuboctahedra. There are a spread of Eu–Eu bond distances ranging from 3.74–3.86 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PmEu3 by Materials Project

Eu3Pm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Eu is bonded to eight equivalent Eu and four equivalent Pm atoms to form EuPm4Eu8 cuboctahedra that share corners with four equivalent PmEu12 cuboctahedra, corners with fourteen equivalent EuPm4Eu8 cuboctahedra, edges with six equivalent PmEu12 cuboctahedra, edges with twelve equivalent EuPm4Eu8 cuboctahedra, faces with four equivalent PmEu12 cuboctahedra, and faces with sixteen equivalent EuPm4Eu8 cuboctahedra. There are a spread of Eu–Eu bond distances ranging from 3.75–3.89 Å. There are two shorter (3.77 Å) and two longer (3.82 Å) Eu–Pm bond lengths. Pm is bonded to twelve equivalent Eu atoms to form PmEu12 cuboctahedra that share corners with six equivalent PmEu12 cuboctahedra, corners with twelve equivalent EuPm4Eu8 cuboctahedra, edges with eighteen equivalent EuPm4Eu8 cuboctahedra, faces with eight equivalent PmEu12 cuboctahedra, and faces with twelve equivalent EuPm4Eu8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu3Ho by Materials Project

HoEu3 is Magnesium-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ho is bonded to twelve equivalent Eu atoms to form HoEu12 cuboctahedra that share corners with six equivalent HoEu12 cuboctahedra, corners with twelve equivalent EuEu8Ho4 cuboctahedra, edges with eighteen equivalent EuEu8Ho4 cuboctahedra, faces with eight equivalent HoEu12 cuboctahedra, and faces with twelve equivalent EuEu8Ho4 cuboctahedra. There are six shorter (3.75 Å) and six longer (3.82 Å) Ho–Eu bond lengths. Eu is bonded to four equivalent Ho and eight equivalent Eu atoms to form EuEu8Ho4 cuboctahedra that share corners with four equivalent HoEu12 cuboctahedra, corners with fourteen equivalent EuEu8Ho4 cuboctahedra, edges with six equivalent HoEu12 cuboctahedra, edges with twelve equivalent EuEu8Ho4 cuboctahedra, faces with four equivalent HoEu12 cuboctahedra, and faces with sixteen equivalent EuEu8Ho4 cuboctahedra. There are a spread of Eu–Eu bond distances ranging from 3.74–3.90 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuEr by Materials Project

ErEu is Magnesium-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Er is bonded to six equivalent Er and six equivalent Eu atoms to form ErEu6Er6 cuboctahedra that share corners with eighteen equivalent ErEu6Er6 cuboctahedra, edges with six equivalent ErEu6Er6 cuboctahedra, edges with twelve equivalent EuEu6Er6 cuboctahedra, faces with eight equivalent ErEu6Er6 cuboctahedra, and faces with twelve equivalent EuEu6Er6 cuboctahedra. All Er–Er bond lengths are 3.66 Å. All Er–Eu bond lengths are 3.69 Å. Eu is bonded to six equivalent Er and six equivalent Eu atoms to form EuEu6Er6 cuboctahedra that share corners with eighteen equivalent EuEu6Er6 cuboctahedra, edges with six equivalent EuEu6Er6 cuboctahedra, edges with twelve equivalent ErEu6Er6 cuboctahedra, faces with eight equivalent EuEu6Er6 cuboctahedra, and faces with twelve equivalent ErEu6Er6 cuboctahedra. All Eu–Eu bond lengths are 3.66 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KEu3 by Materials Project

KEu3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. K is bonded to twelve equivalent Eu atoms to form KEu12 cuboctahedra that share corners with twelve equivalent KEu12 cuboctahedra, edges with twenty-four equivalent EuK4Eu8 cuboctahedra, faces with six equivalent KEu12 cuboctahedra, and faces with twelve equivalent EuK4Eu8 cuboctahedra. All K–Eu bond lengths are 4.16 Å. Eu is bonded to four equivalent K and eight equivalent Eu atoms to form EuK4Eu8 cuboctahedra that share corners with twelve equivalent EuK4Eu8 cuboctahedra, edges with eight equivalent KEu12 cuboctahedra, edges with sixteen equivalent EuK4Eu8 cuboctahedra, faces with four equivalent KEu12 cuboctahedra, and faces with fourteen equivalent EuK4Eu8 cuboctahedra. All Eu–Eu bond lengths are 4.16 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuNi9Ge4 by Materials Project

EuNi9Ge4 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Eu is bonded in a 8-coordinate geometry to sixteen Ni and eight equivalent Ge atoms. There are eight shorter (3.43 Å) and eight longer (3.48 Å) Eu–Ni bond lengths. All Eu–Ge bond lengths are 3.40 Å. There are three inequivalent Ni sites. In the first Ni site, Ni is bonded in a 12-coordinate geometry to two equivalent Eu, six Ni, and four equivalent Ge atoms. There are a spread of Ni–Ni bond distances ranging from 2.43–2.66 Å. There are two shorter (2.55 Å) and two longer (2.59 Å) Ni–Ge bond lengths. In the second Ni site, Ni is bonded in a cuboctahedral geometry to eight Ni and four equivalent Ge atoms. All Ni–Ni bond lengths are 2.45 Å. All Ni–Ge bond lengths are 2.43 Å. In the third Ni site, Ni is bonded in a 12-coordinate geometry to two equivalent Eu, eight Ni, and two equivalent Ge atoms. There are two shorter (2.49 Å) and one longer (2.72 Å) Ni–Ni bond lengths. Both Ni–Ge bond lengths are 2.52 Å. Ge is bonded in a 12-coordinate geometry to two equivalent Eu, seven Ni, and three equivalent Ge atoms. There are two shorter (2.68 Å) and one longer (2.70 Å) Ge–Ge bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Impact of europium and samarium on growth and metabolism of two anaerobic wastewater microorganisms: Sporacetigenium mesophilum and Clostridium sporogenes

Increases in environmental fluxes of rare earth elements (REEs) stemming from increased demand for these technology critical elements may affect microbial ecosystem functions important for pollutant degradation and nutrient cycling. Here, this study investigates the responses of Sporacetigenium mesophilum and Clostridium sporogenes, two anaerobic fermenters, to varying concentrations of two REE, namely europium and samarium. Eu and Sm are adjacent lanthanides but differ significantly in their redox behavior. We tested Eu and Sm concentrations ranging from < 1 to 600 µM. Despite the close phylogenetic relatedness of the two bacteria, we observed species-specific as well as REE-specific and incubation time-dependent sensitivities. S. mesophilum exhibited pronounced inhibition of hydrogen production and growth with exposure to ≥ 60 µM of Eu, but with 6 µM Eu, a hormetic effect was observed—hydrogen production was enhanced relative to the control. With Sm, the only impact observed on S. mesophilum was inhibition at the highest concentration (600 µM) tested. For C. sporogenes, growth inhibition was observed only at 600 µM Eu or Sm, and no hormesis was observed with either REE. This study offers both significant benefits and novelty by addressing the emerging environmental concern of REE pollution, particularly the effects of Eu and Sm on anaerobic microorganisms relevant to wastewater treatment. It provides valuable insights into REE impacts under anaerobic conditions, which are essential for understanding potential disruptions to organic matter degradation and nutrient cycling processes.

60 - APPLIED LIFE SCIENCES↗
DOE OSTI2023

Solution Structures of Europium Terpyridyl Complexes with Nitrate and Triflate Counterions in Acetonitrile

Lanthanide–ligand complexes are key components of technological applications, and their properties depend on their structures in the solution phase, which are challenging to resolve experimentally or computationally. The coordination structure of the Eu 3+ ion in different coordination environments in acetonitrile is examined using ab initio molecular dynamics (AIMD) simulations and extended X-ray absorption fine structure (EXAFS) spectroscopy. AIMD simulations are conducted for the solvated Eu 3+ ion in acetonitrile, both with or without a terpyridyl ligand, and in the presence of either triflate or nitrate counterions. EXAFS spectra are calculated directly from AIMD simulations and then compared to experimentally measured EXAFS spectra. In acetonitrile solution, both nitrate and triflate anions are shown to coordinate directly to the Eu 3+ ion forming either ten- or eight-coordinate solvent complexes where the counterions are binding as bidentate or monodentate structures, respectively. Coordination of a terpyridyl ligand to the Eu 3+ ion limits the available binding sites for the solvent and anions. In certain cases, the terpyridyl ligand excludes any solvent binding and limits the number of coordinated anions. The solution structure of the Eu-terpyridyl complex with nitrate counterions is shown to have a similar arrangement of Eu 3+ coordinating molecules as the crystal structure. Finally, this study illustrates how a combination of AIMD and EXAFS can be used to determine how ligands, solvent, and counterions coordinate with the lanthanide ions in solution.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Using molten salts to probe outer-coordination sphere effects on lanthanide( III )/( II ) electron-transfer reactions

Controlling structure and reactivity by manipulating the outer-coordination sphere around a given reagent represents a longstanding challenge in chemistry. Despite advances toward solving this problem, it remains difficult to experimentally interrogate and characterize outer-coordination sphere impact. Here, this work describes an alternative approach that quantifies outer-coordination sphere effects. It shows how molten salt metal chlorides (MCl n ; M = K, Na, n = 1; M = Ca, n = 2) provided excellent platforms for experimentally characterizing the influence of the outer-coordination sphere cations (M n+ ) on redox reactions accessible to lanthanide ions; Ln 3+ + e 1– → Ln 2+ (Ln = Eu, Yb, Sm; e 1– = electron). As a representative example, X-ray absorption spectroscopy and cyclic voltammetry results showed that Eu 2+ instantaneously formed when Eu 3+ dissolved in molten chloride salts that had strongly polarizing cations (like Ca 2+ from CaCl 2 ) via the Eu 3+ + Cl 1– → Eu 2+ + ½Cl 2 reaction. Conversely, molten salts with less polarizing outer-sphere M 1+ cations (e.g., K 1+ in KCl) stabilized Ln 3+ . For instance, the Eu 3+ /Eu 2+ reduction potential was >0.5 V more positive in CaCl 2 than in KCl. In accordance with first-principle molecular dynamics (FPMD) simulations, we postulated that hard M n+ cations (high polarization power) inductively removed electron density from Ln n+ across Ln–Cl···M n+ networks and stabilized electron-rich and low oxidation state Ln 2+ ions. Conversely, less polarizing M n+ cations (like K 1+ ) left electron density on Lnn+ and stabilized electron-deficient and high-oxidation state Ln 3+ ions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗