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At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Role of Bifunctional Ru/Acid Catalysts in the Selective Hydrocracking of Polyethylene and Polypropylene Waste to Liquid Hydrocarbons

Hydrogenolysis of C–C bonds over Ru-based catalysts has emerged as a deconstruction strategy to convert single-use polyolefin waste to liquid alkanes at relatively mild conditions, but this approach exhibits limitations, including methane formation resulting from terminal C–C bond scission. In this study, a variety of catalysts were investigated for the reductive deconstruction of polyethylene (PE) and polypropylene (PP) to identify supports that promote nonterminal C–C bond scission. We found that Ru nanoparticles supported on Brønsted-acidic zeolites with the faujasite (FAU) and Beta (BEA) topologies were highly active for the cleavage of C–C bonds in PE and PP, exhibiting improved liquid yields and suppressed methane formation. For the deconstruction of PE, supporting ruthenium nanoparticles (5 wt %) on FAU increased the yields of liquid alkanes to 67% compared to 33% over an inert silica support (5 wt % Ru/SiO 2 ) at 200 °C, 16 h, under 30 bar of H2. A dramatic selectivity enhancement toward liquid hydrocarbons was also observed for PP over Ru/FAU and Ru/BEA compared to Ru/SiO 2 . To understand the origin of this selectivity improvement, a combination of ex situ and operando characterization techniques were used to reveal that both catalyst structure and acidity play key roles in PE and PP conversion. Operando X-ray absorption spectroscopy studies with model polyolefins over Ru-supported catalysts with varying acidity levels revealed that the local chemical environment of Ru [0] during the reaction is consistent across multiple acidic supports, although the onset of reduction during synthesis of the nanoparticles varies across different supports. These results, combined with reactivity data, demonstrate the importance of the acid-noble metal cooperativity in promoting selective C–C bond scission toward liquid alkanes that shifts the mechanism from hydrogenolysis to ideal hydrocracking.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Etching-Chemistry-Driven Ruthenium Doping on Ti 3 C 2 T x MXene for Optimizing Electrochemical Performance

We demonstrate that the etching chemistry used during MXene synthesis from Ti 3 AlC 2 MAX phase significantly influences surface functionalization and structural vacancies, which in turn affect ruthenium (Ru) ion interactions. Using hydrofluoric acid (HF) and ammonium bifluoride (NH 4 HF 2 ) as etchants, we obtained MXene surfaces with distinct functional groups and Ti vacancies that impact Ru ion interactions and electrochemical performance. Both MXene variants (labeled MX(H) and MX(N), respectively) exhibited negative zeta potentials in their pristine state, but upon the addition of Ru the zeta potential for MX(H) reached 12.9 mV while that for MX(N) remained negative at −6.4 mV. This adsorption resulted in a 14.4-fold increase in the specific capacitance of MX(H)/Ru compared to pristine MX(H), whereas MX(N)/Ru exhibited only a 4.4-fold increase over its pristine counterpart. X-ray diffraction analysis identified the formation of ammonium titanium oxide fluoride, (NH 4 ) 3 TiOF 5 , on MX(N), which likely contributed to its reduced Ru adsorption. X-ray photoelectron spectroscopy suggested the presence of Ti vacancies in both MXene variants; however, their behavior toward Ru accommodation differed markedly, with MX(H) showing the most obvious shift in the Ti 2p peak in the XPS survey spectrum, while MX(N) showed the most obvious shift in the C 1s peak. Electron paramagnetic resonance spectroscopy further demonstrated a distinct alteration in the spectral signatures of MX(H) upon Ru addition, in contrast to the negligible changes in MX(N), indicating effective passivation of the Ti defect sites in MX(H) via vacancy-assisted Ru doping. Cyclic voltammetry showed that Ru-incorporated MX(H) nanocomposites exhibit more efficient redox-active sites, as reflected in their higher capacitance values. These findings highlight the pivotal role of MXene surface chemistry in controlling cation adsorption, providing valuable insights for the rational design of high-performance electrodes.

2D surface engineering↗
DOE OSTI2024

Enhanced nucleation mechanism in ruthenium atomic layer deposition: Exploring surface termination and precursor ligand effects with RuCpEt(CO)2

Miniaturization of microelectronic devices necessitates atomic precision in manufacturing techniques, particularly in the deposition of thin films. Atomic layer deposition (ALD) is recognized for its precision in controlling film thickness and composition on intricate three-dimensional structures. This study focuses on the ALD nucleation and growth mechanisms of ruthenium (Ru), a metal that has significant future implications for microelectronics. Despite its advantages, the deposition of a high surface-free energy material like Ru on a low surface-free energy material such as an oxide often faces challenges of large nucleation delays and non-uniform growth. To address these challenges, we explored the effectiveness of organometallic surface pretreatments using trimethylaluminum (TMA) or diethylzinc (DEZ) to enhance Ru film nucleation and growth. Our study employed a less-studied Ru precursor, cyclopentadienylethyl(dicarbonyl)ruthenium [RuCpEt(CO)2], which demonstrated promising results in terms of reduced nucleation delay and increased film continuity. Ru ALD was performed on silicon substrates with native oxide, using RuCpEt(CO)2 and O2 as coreactants. Our findings reveal that surface pretreatment significantly improves nucleation density and film thickness within the initial 60 ALD cycles, achieving up to a 3.2-fold increase in Ru surface coverage compared to nonpretreated substrates. Supported by density functional theory calculations, we propose that the enhanced nucleation observed with RuCpEt(CO)2 compared to previously-studied Ru(Cp)2 is due to two key mechanisms: the facilitated removal of CO ligands during deposition, which enhances the reactivity of the precursor, and a hydrogen-abstraction reaction involving the ethyl ligand of RuCpEt(CO)2 and the metal-alkyl groups on the surface. This study not only advances our understanding of Ru ALD processes but also highlights the significant impact of precursor chemistry and surface treatments in optimizing ALD for advanced microelectronic applications.

Materials Science↗
DOE OSTI2024

Liquid organic hydrogen carriers for long-duration energy storage

Liquid organic hydrogen carrier (LOHC) systems are an excellent alternative to pressurized gas and liquid hydrogen storage technologies due to their high volumetric storage capacities and straightforward adaptation to existing infrastructure. Here, we investigate various molecular and heterogenized Ru, Mn, and Fe catalysts for the reversible (de)hydrogenation of polyols. Mn catalysts, Mn-MACHO(Ph) (1) and Mn-MACHO(iPr)BH 4 (2-BH 4 ) were found to maintain catalytic activity for hydrogen production comparable to the Ru analogs, with greater than 98% conversion of 1,4 butanediol and quantitative hydrogen production. Furthermore, to assess the viability of utilizing heterogenized molecular catalysts for 1,4 butanediol (de)hydrogenation, molecular catalysts, Mn-MACHO(Ph), Ru-MACHO(Ph), and Ru-9, were polymerized to form Mn-MACHO-Poly, Ru-MACHO-Poly, and Ru-9-Poly respectively. These catalysts were then used to assess (de)hydrogenation of polyols, ethylene glycol and 1,4 butanediol. These studies reveal that Ru-MACHO-Poly is an efficient dehydrogenation catalyst with 99% conversion and a hydrogen percent yield of 96%. In addition, Ru-MACHO-Poly is a competent hydrogenation catalyst with approximately 98% conversion back to 1,4 butanediol based on quantitative NMR measurements. Overall, the data suggest these molecular and heterogenized catalysts have potential for practical use in polyalcohol-based LOHC systems.

08 HYDROGEN↗
DOE OSTI2020

Materials Data on Pr3RuI3 by Materials Project

Pr3I3Ru crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent Pr sites. In the first Pr site, Pr is bonded to two equivalent Ru and four I atoms to form distorted PrRu2I4 octahedra that share corners with four equivalent PrRu3I3 octahedra and edges with eight PrRu2I4 octahedra. The corner-sharing octahedra tilt angles range from 4–8°. Both Pr–Ru bond lengths are 2.88 Å. There are a spread of Pr–I bond distances ranging from 3.29–3.54 Å. In the second Pr site, Pr is bonded in a 6-coordinate geometry to one Ru and five I atoms. The Pr–Ru bond length is 2.67 Å. There are a spread of Pr–I bond distances ranging from 3.24–3.65 Å. In the third Pr site, Pr is bonded to three equivalent Ru and three I atoms to form a mixture of distorted edge and corner-sharing PrRu3I3 octahedra. The corner-sharing octahedra tilt angles range from 4–8°. There are one shorter (2.90 Å) and two longer (2.91 Å) Pr–Ru bond lengths. There are one shorter (3.51 Å) and two longer (3.59 Å) Pr–I bond lengths. Ru is bonded to six Pr atoms to form RuPr6 octahedra that share corners with four equivalent IPr5 square pyramids, edges with four equivalent RuPr6 octahedra, and edges with four equivalent IPr5 square pyramids. There are three inequivalent I sites. In the first I site, I is bonded in a distorted see-saw-like geometry to four Pr atoms. In the second I site, I is bonded in a distorted T-shaped geometry to three Pr atoms. In the third I site, I is bonded to five Pr atoms to form distorted IPr5 square pyramids that share corners with four equivalent RuPr6 octahedra, edges with four equivalent RuPr6 octahedra, and edges with four equivalent IPr5 square pyramids. The corner-sharing octahedra tilt angles range from 12–13°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y3RuI3 by Materials Project

Y3RuI3 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent Y sites. In the first Y site, Y is bonded to three equivalent Ru and three I atoms to form distorted edge-sharing YRu3I3 octahedra. There are two shorter (2.74 Å) and one longer (2.84 Å) Y–Ru bond lengths. There are one shorter (3.29 Å) and two longer (3.37 Å) Y–I bond lengths. In the second Y site, Y is bonded in a 6-coordinate geometry to one Ru and five I atoms. The Y–Ru bond length is 2.76 Å. There are a spread of Y–I bond distances ranging from 3.13–3.60 Å. In the third Y site, Y is bonded in a 6-coordinate geometry to two equivalent Ru and four I atoms. Both Y–Ru bond lengths are 2.80 Å. There are a spread of Y–I bond distances ranging from 3.26–3.52 Å. Ru is bonded to six Y atoms to form distorted edge-sharing RuY6 octahedra. There are three inequivalent I sites. In the first I site, I is bonded in a distorted T-shaped geometry to three Y atoms. In the second I site, I is bonded in a 4-coordinate geometry to four Y atoms. In the third I site, I is bonded in a 5-coordinate geometry to five Y atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y4RuI5 by Materials Project

Y4RuI5 crystallizes in the tetragonal P4_2/nnm space group. The structure is three-dimensional. there are three inequivalent Y sites. In the first Y site, Y is bonded in a 6-coordinate geometry to one Ru and five I atoms. The Y–Ru bond length is 2.71 Å. There are a spread of Y–I bond distances ranging from 3.13–3.54 Å. In the second Y site, Y is bonded to three equivalent Ru and three I atoms to form edge-sharing YRu3I3 octahedra. There are two shorter (2.84 Å) and one longer (2.86 Å) Y–Ru bond lengths. There are one shorter (3.24 Å) and two longer (3.38 Å) Y–I bond lengths. In the third Y site, Y is bonded in a 6-coordinate geometry to one Ru and five I atoms. The Y–Ru bond length is 2.69 Å. There are a spread of Y–I bond distances ranging from 3.13–3.56 Å. Ru is bonded to six Y atoms to form edge-sharing RuY6 octahedra. There are four inequivalent I sites. In the first I site, I is bonded in a 3-coordinate geometry to three Y atoms. In the second I site, I is bonded in a distorted see-saw-like geometry to four Y atoms. In the third I site, I is bonded in a distorted see-saw-like geometry to four Y atoms. In the fourth I site, I is bonded in a 3-coordinate geometry to three Y atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y6RuI10 by Materials Project

Y6RuI10 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent Y sites. In the first Y site, Y is bonded to one Ru and five I atoms to form a mixture of distorted edge and corner-sharing YRuI5 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. The Y–Ru bond length is 2.68 Å. There are a spread of Y–I bond distances ranging from 3.11–3.37 Å. In the second Y site, Y is bonded to one Ru and five I atoms to form a mixture of distorted edge and corner-sharing YRuI5 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. The Y–Ru bond length is 2.68 Å. There are a spread of Y–I bond distances ranging from 3.06–3.41 Å. In the third Y site, Y is bonded to one Ru and five I atoms to form a mixture of edge and corner-sharing YRuI5 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. The Y–Ru bond length is 2.78 Å. There are a spread of Y–I bond distances ranging from 3.03–3.31 Å. Ru is bonded in an octahedral geometry to six Y atoms. There are five inequivalent I sites. In the first I site, I is bonded in a distorted L-shaped geometry to two Y atoms. In the second I site, I is bonded in a distorted T-shaped geometry to three Y atoms. In the third I site, I is bonded in a distorted T-shaped geometry to three Y atoms. In the fourth I site, I is bonded in a distorted see-saw-like geometry to four Y atoms. In the fifth I site, I is bonded in a 3-coordinate geometry to three Y atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy5Ru2 by Materials Project

Dy5Ru2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Dy sites. In the first Dy site, Dy is bonded in a 2-coordinate geometry to three equivalent Ru atoms. There are a spread of Dy–Ru bond distances ranging from 2.74–3.40 Å. In the second Dy site, Dy is bonded to four equivalent Ru atoms to form distorted edge-sharing DyRu4 tetrahedra. There are two shorter (2.89 Å) and two longer (2.95 Å) Dy–Ru bond lengths. In the third Dy site, Dy is bonded in a 3-coordinate geometry to three equivalent Ru atoms. There are a spread of Dy–Ru bond distances ranging from 2.83–3.04 Å. Ru is bonded in a 7-coordinate geometry to eight Dy atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce7Ru3 by Materials Project

Ce7Ru3 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. there are three inequivalent Ce sites. In the first Ce site, Ce is bonded in a distorted water-like geometry to four equivalent Ru atoms. There are two shorter (2.83 Å) and two longer (3.42 Å) Ce–Ru bond lengths. In the second Ce site, Ce is bonded in a 3-coordinate geometry to four equivalent Ru atoms. There are a spread of Ce–Ru bond distances ranging from 2.70–3.40 Å. In the third Ce site, Ce is bonded in a 3-coordinate geometry to three equivalent Ru atoms. All Ce–Ru bond lengths are 2.97 Å. Ru is bonded in a 6-coordinate geometry to nine Ce atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi4RuI2 by Materials Project

RuBi4I2 crystallizes in the tetragonal I4/m space group. The structure is one-dimensional and consists of two RuBi4I2 ribbons oriented in the (0, 0, 1) direction. Ru is bonded in a 8-coordinate geometry to one Ru and eight Bi atoms. The Ru–Ru bond length is 2.88 Å. There are four shorter (2.80 Å) and four longer (2.94 Å) Ru–Bi bond lengths. There are two inequivalent Bi sites. In the first Bi site, Bi is bonded in a 2-coordinate geometry to two equivalent Ru and two equivalent Bi atoms. Both Bi–Bi bond lengths are 3.04 Å. In the second Bi site, Bi is bonded in a 4-coordinate geometry to two equivalent Ru and two equivalent I atoms. There are one shorter (3.22 Å) and one longer (3.24 Å) Bi–I bond lengths. I is bonded in a 2-coordinate geometry to two equivalent Bi atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba3BiRu2O9 by Materials Project

Ba3Ru2BiO9 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.79–3.36 Å. In the second Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.80–3.37 Å. Ru+4.50+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BiO6 octahedra and a faceface with one RuO6 octahedra. The corner-sharing octahedra tilt angles range from 9–15°. There are a spread of Ru–O bond distances ranging from 1.97–2.06 Å. Bi3+ is bonded to six O2- atoms to form BiO6 octahedra that share corners with six equivalent RuO6 octahedra. The corner-sharing octahedra tilt angles range from 9–15°. There are four shorter (2.30 Å) and two longer (2.32 Å) Bi–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ba2+ and two equivalent Ru+4.50+ atoms to form distorted corner-sharing OBa4Ru2 octahedra. The corner-sharing octahedral tilt angles are 5°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two equivalent Ru+4.50+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+, one Ru+4.50+, and one Bi3+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to four Ba2+, one Ru+4.50+, and one Bi3+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+, one Ru+4.50+, and one Bi3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErRu3 by Materials Project

ErRu3 is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Er is bonded to twelve Ru atoms to form a mixture of edge, corner, and face-sharing ErRu12 cuboctahedra. There are four shorter (2.84 Å) and eight longer (2.86 Å) Er–Ru bond lengths. There are two inequivalent Ru sites. In the first Ru site, Ru is bonded to four equivalent Er atoms to form a mixture of distorted edge and corner-sharing RuEr4 cuboctahedra. In the second Ru site, Ru is bonded in a distorted square co-planar geometry to four equivalent Er atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y4CdRu by Materials Project

Y4RuCd crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are three inequivalent Y sites. In the first Y site, Y is bonded in a 4-coordinate geometry to two equivalent Ru and two equivalent Cd atoms. Both Y–Ru bond lengths are 3.47 Å. Both Y–Cd bond lengths are 3.30 Å. In the second Y site, Y is bonded in a 3-coordinate geometry to three equivalent Ru and three equivalent Cd atoms. All Y–Ru bond lengths are 2.85 Å. All Y–Cd bond lengths are 3.48 Å. In the third Y site, Y is bonded in a distorted bent 150 degrees geometry to two equivalent Ru and two equivalent Cd atoms. Both Y–Ru bond lengths are 2.78 Å. Both Y–Cd bond lengths are 3.51 Å. Ru is bonded in a 6-coordinate geometry to nine Y atoms. Cd is bonded to nine Y and three equivalent Cd atoms to form a mixture of corner and face-sharing CdY9Cd3 cuboctahedra. All Cd–Cd bond lengths are 3.09 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La4CdRu by Materials Project

La4RuCd crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are three inequivalent La sites. In the first La site, La is bonded in a 3-coordinate geometry to three equivalent Ru and three equivalent Cd atoms. All La–Ru bond lengths are 3.00 Å. All La–Cd bond lengths are 3.66 Å. In the second La site, La is bonded in a distorted bent 150 degrees geometry to two equivalent Ru and two equivalent Cd atoms. Both La–Ru bond lengths are 2.86 Å. Both La–Cd bond lengths are 3.67 Å. In the third La site, La is bonded in a 4-coordinate geometry to two equivalent Ru and two equivalent Cd atoms. Both La–Ru bond lengths are 3.61 Å. Both La–Cd bond lengths are 3.46 Å. Ru is bonded in a 6-coordinate geometry to nine La atoms. Cd is bonded to nine La and three equivalent Cd atoms to form a mixture of corner and face-sharing CdLa9Cd3 cuboctahedra. All Cd–Cd bond lengths are 3.18 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr6RuBr10 by Materials Project

Pr6RuBr10 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent Pr sites. In the first Pr site, Pr is bonded to one Ru and five Br atoms to form a mixture of edge and corner-sharing PrRuBr5 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. The Pr–Ru bond length is 2.90 Å. There are a spread of Pr–Br bond distances ranging from 2.98–3.25 Å. In the second Pr site, Pr is bonded to one Ru and five Br atoms to form a mixture of edge and corner-sharing PrRuBr5 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. The Pr–Ru bond length is 2.93 Å. There are a spread of Pr–Br bond distances ranging from 2.88–3.20 Å. In the third Pr site, Pr is bonded to one Ru and five Br atoms to form a mixture of edge and corner-sharing PrRuBr5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. The Pr–Ru bond length is 2.65 Å. There are a spread of Pr–Br bond distances ranging from 2.98–3.28 Å. Ru is bonded in an octahedral geometry to six Pr atoms. There are five inequivalent Br sites. In the first Br site, Br is bonded in a distorted trigonal non-coplanar geometry to three Pr atoms. In the second Br site, Br is bonded in an L-shaped geometry to two Pr atoms. In the third Br site, Br is bonded in a T-shaped geometry to three Pr atoms. In the fourth Br site, Br is bonded in a see-saw-like geometry to four Pr atoms. In the fifth Br site, Br is bonded in a T-shaped geometry to three Pr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th7Ru3 by Materials Project

Th7Ru3 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. there are three inequivalent Th sites. In the first Th site, Th is bonded in a distorted water-like geometry to two equivalent Ru atoms. Both Th–Ru bond lengths are 2.85 Å. In the second Th site, Th is bonded in a 3-coordinate geometry to three equivalent Ru atoms. There are two shorter (2.86 Å) and one longer (3.06 Å) Th–Ru bond lengths. In the third Th site, Th is bonded in a 3-coordinate geometry to three equivalent Ru atoms. All Th–Ru bond lengths are 2.97 Å. Ru is bonded in a 6-coordinate geometry to six Th atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd4MgRu by Materials Project

MgNd4Ru crystallizes in the cubic F-43m space group. The structure is three-dimensional. Mg is bonded to three equivalent Mg and nine Nd atoms to form a mixture of face and corner-sharing MgNd9Mg3 cuboctahedra. All Mg–Mg bond lengths are 3.15 Å. There are three shorter (3.44 Å) and six longer (3.66 Å) Mg–Nd bond lengths. There are three inequivalent Nd sites. In the first Nd site, Nd is bonded in a bent 150 degrees geometry to two equivalent Mg and two equivalent Ru atoms. Both Nd–Ru bond lengths are 2.86 Å. In the second Nd site, Nd is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg and two equivalent Ru atoms. Both Nd–Ru bond lengths are 3.60 Å. In the third Nd site, Nd is bonded in a 3-coordinate geometry to three equivalent Mg and three equivalent Ru atoms. All Nd–Ru bond lengths are 2.95 Å. Ru is bonded in a 6-coordinate geometry to nine Nd atoms.

36 MATERIALS SCIENCE↗