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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Caffeic acid attenuates irradiation-induced hematopoietic stem cell apoptosis through inhibiting mitochondrial damage

Highlights: • IR-induced mitochondrial damage accelerates HSC apoptosis. • CA attenuates mitochondrial damage and apoptosis of HSCs induced by IR. • CA protects against BM hematopoietic failure in mice after IR exposure. Hematopoietic stem cells (HSCs) are sensitive to ionizing radiation (IR) damage, and its injury is the primary cause of bone marrow (BM) hematopoietic failure and even death after exposure to a certain dose of IR. However, the underlying mechanisms remain incompletely understood. Here we show that mitochondrial oxidative damage, which is characterized by mitochondrial reactive oxygen species overproduction, mitochondrial membrane potential reduction and mitochondrial permeability transition pore opening, is rapidly induced in both human and mouse HSCs and directly accelerates HSC apoptosis after IR exposure. Mechanistically, 5-lipoxygenase (5-LOX) is induced by IR exposure and contributes to IR-induced mitochondrial oxidative damage through inducing lipid peroxidation. Intriguingly, a natural antioxidant, caffeic acid (CA), can attenuate IR-induced HSC apoptosis through suppressing 5-LOX-mediated mitochondrial oxidative damage, thus protecting against BM hematopoietic failure after IR exposure. These findings uncover a critical role for mitochondria in IR-induced HSC injury and highlight the therapeutic potential of CA in BM hematopoietic failure induced by IR.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

Broadband Fourier-Transform Optical Photothermal Infrared Spectroscopy and Imaging

Infrared (IR) spectroscopy is a powerful method for mapping chemical heterogeneity on the microscale. Synchrotron IR radiation uniquely provides a high brightness and broad bandwidth to further extend the capabilities of IR spectroscopic imaging. However, the diffraction-limited spatial resolution of IR spectroscopy is insufficient for studies requiring submicrometer spatial differentiation. Optical photothermal IR (O-PTIR) microscopy is a powerful, emerging method that overcomes the IR diffraction limit in IR hyperspectral imaging by employing a modulated IR beam and a visible probe laser beam to detect local temperature-induced modulation at the visible diffraction limit. In this work, we extend the spectral range of photothermal infrared measurements by incorporating a synchrotron IR source, demonstrating a combined synchrotron-based O-PTIR modality that enables high spatial resolution far-field chemical imaging spanning the entire mid-IR range. Both optical- and fluorescence-detected photothermal modalities were performed using a step-scan interferometer, demonstrating improved spectral range (541-4000 cm-1) when compared to optical photothermal microscopy with commercial laser sources (800-1800 cm-1 for this particular source) and improved spatial resolution, when compared to synchrotron microspectroscopy measurements. Following these initial validation studies, synchrotron Fourier-transform fluorescence-detected photothermal IR spectroscopy in combination with synchrotron microspectroscopy measurements was used to differentiate cells in mouse brain tissue sections, which requires submicron spatial resolutions beyond those accessible by IR spectroscopy alone.

Razumtcev, Aleksandr↗
DOE OSTI2026

Impact of Porous Transport Layer Morphology on the Performance of Proton Exchange Membrane Water Electrolyzers with Ultra-Low Iridium Loadings

Reducing Ir loadings in proton exchange membrane water electrolyzer anodes is critical for lowering capital expenses. Loading reduction could be achieved by improving the Ir activity via doping/alloying and/or the development of advanced microstructures. However, the anode porous transport layer (PTL) is a comparatively simple component whose properties also impact Ir utilization. Therefore, well-designed PTLs may also enable reduced Ir loadings. In this work, we survey eight PTLs from various manufacturers to observe their impact on cell performance at low (0.4 mg Ir cm -2 ) and ultralow (0.1 mg Ir cm -2 ) Ir loadings. The PTLs were characterized by their microstructural properties, including porosity, particle size distribution, and pore size distribution. Electrochemical cell performance was correlated to PTL morphology, and it was found that PTLs with lower porosities and smaller particle and pore radii enabled good performance even at ultralow Ir loadings. 1000-h durability testing indicated that using lower porosity PTLs can significantly improve durability behavior. A runaway voltage phenomenon was observed during durability testing of cells with ultralow Ir loadings, which was caused by increases in both anode and cathode overpotentials. Furthermore, we observed that the beginning of test performance of 0.1 mg Ir cm -2 cells correlates to the 1000-h degradation rates of 0.4 mg Ir cm -2 cells, suggesting that for the Ir catalyst used in this work, short-term testing at ultralow loadings can be used as an indicator of long-term degradation at higher loadings.

08 HYDROGEN↗
DOE OSTI2024

High-Performance Iridium–Molybdenum Oxide Electrocatalysts for Water Oxidation in Acid: Bayesian Optimization Discovery and Experimental Testing

Ir oxides are costly and scarce catalysts for oxygen evolution reaction (OER) in acid. There has been extensive interest in developing alternatives that are either Ir-free or require smaller amounts of Ir to drive the reactions at acceptable rates. One design strategy is to identify Ir-based mixed oxides that achieve similar performance while requiring smaller amounts of Ir. The obstacle to this strategy has been a very large phase space of the Ir-based mixed metal oxides, in terms of the metals combined with Ir and the different crystallographic structures of the mixed oxides, which prevents a thorough exploration of possible materials. In this work, we developed a workflow that uses machine-learning-aided Bayesian optimization in combination with density functional theory to make the exploration of this phase space plausible. This screening identified Mo as a promising dopant for forming acid-tolerant Ir-based oxides for the OER. We synthesized and characterized the Ir–Mo mixed oxides in the form of thin-film electrocatalysts with a known surface area. We show that these mixed oxides exhibited overpotentials ~30 mV lower than a pure Ir control while maintaining 24% lower Ir dissolution rates than the Ir control. Furthermore, these findings suggest that Mo is a promising dopant and highlight the promise of machine learning to guide the experimental exploration and optimization of catalytic materials.

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

Long-Term Effects of Very Low Dose Particle Radiation on Gene Expression in the Heart: Degenerative Disease Risks

Compared to low doses of gamma irradiation (γ-IR), high-charge-and-energy (HZE) particle IR may have different biological response thresholds in cardiac tissue at lower doses, and these effects may be IR type and dose dependent. Three- to four-month-old female CB6F1/Hsd mice were exposed once to one of four different doses of the following types of radiation: γ-IR 137Cs (40-160 cGy, 0.662 MeV), 14Si-IR (4-32 cGy, 260 MeV/n), or 22Ti-IR (3-26 cGy, 1 GeV/n). At 16 months post-exposure, animals were sacrificed and hearts were harvested and archived as part of the NASA Space Radiation Tissue Sharing Forum. These heart tissue samples were used in our study for RNA isolation and microarray hybridization. Functional annotation of twofold up/down differentially expressed genes (DEGs) and bioinformatics analyses revealed the following: (i) there were no clear lower IR thresholds for HZE- or γ-IR; (ii) there were 12 common DEGs across all 3 IR types; (iii) these 12 overlapping genes predicted various degrees of cardiovascular, pulmonary, and metabolic diseases, cancer, and aging; and (iv) these 12 genes revealed an exclusive non-linear DEG pattern in 14Si- and 22Ti-IR-exposed hearts, whereas two-thirds of γ-IR-exposed hearts revealed a linear pattern of DEGs. Thus, our study may provide experimental evidence of excess relative risk (ERR) quantification of low/very low doses of full-body space-type IR-associated degenerative disease development.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2020

Materials Data on LaPIr by Materials Project

LaIrP is hexagonal omega structure-derived structured and crystallizes in the tetragonal I4_1md space group. The structure is three-dimensional. La is bonded to six equivalent Ir and six equivalent P atoms to form a mixture of edge and face-sharing LaP6Ir6 cuboctahedra. There are two shorter (3.12 Å) and four longer (3.21 Å) La–Ir bond lengths. There are four shorter (3.16 Å) and two longer (3.23 Å) La–P bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 9-coordinate geometry to six equivalent La and three equivalent P atoms. All Ir–P bond lengths are 2.40 Å. In the second Ir site, Ir is bonded in a 9-coordinate geometry to six equivalent La and three equivalent P atoms. There are two shorter (3.12 Å) and four longer (3.21 Å) Ir–La bond lengths. All Ir–P bond lengths are 2.40 Å. P is bonded in a 9-coordinate geometry to six equivalent La and three equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NdPIr by Materials Project

NdIrP is hexagonal omega structure-derived structured and crystallizes in the tetragonal I4_1md space group. The structure is three-dimensional. Nd is bonded to six equivalent Ir and six equivalent P atoms to form a mixture of edge and face-sharing NdP6Ir6 cuboctahedra. There are two shorter (3.09 Å) and four longer (3.17 Å) Nd–Ir bond lengths. There are four shorter (3.12 Å) and two longer (3.20 Å) Nd–P bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 9-coordinate geometry to six equivalent Nd and three equivalent P atoms. There are two shorter (2.37 Å) and one longer (2.38 Å) Ir–P bond lengths. In the second Ir site, Ir is bonded in a 9-coordinate geometry to six equivalent Nd and three equivalent P atoms. There are two shorter (3.09 Å) and four longer (3.17 Å) Ir–Nd bond lengths. There are two shorter (2.37 Å) and one longer (2.38 Å) Ir–P bond lengths. P is bonded in a 9-coordinate geometry to six equivalent Nd and three equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce(SnIr)2 by Materials Project

Ce(IrSn)2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Ce is bonded in a 12-coordinate geometry to eight Ir and eight Sn atoms. There are four shorter (3.40 Å) and four longer (3.50 Å) Ce–Ir bond lengths. There are four shorter (3.38 Å) and four longer (3.56 Å) Ce–Sn bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Ce and five Sn atoms. There are one shorter (2.59 Å) and four longer (2.66 Å) Ir–Sn bond lengths. In the second Ir site, Ir is bonded to four equivalent Ce and four equivalent Sn atoms to form distorted IrCe4Sn4 tetrahedra that share corners with twelve equivalent SnCe4Ir4 tetrahedra, edges with two equivalent SnCe4Ir4 tetrahedra, edges with four equivalent IrCe4Sn4 tetrahedra, and faces with four equivalent IrCe4Sn4 tetrahedra. All Ir–Sn bond lengths are 2.64 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 9-coordinate geometry to four equivalent Ce and five Ir atoms. In the second Sn site, Sn is bonded to four equivalent Ce and four equivalent Ir atoms to form distorted SnCe4Ir4 tetrahedra that share corners with twelve equivalent IrCe4Sn4 tetrahedra, edges with two equivalent IrCe4Sn4 tetrahedra, edges with four equivalent SnCe4Ir4 tetrahedra, and faces with four equivalent SnCe4Ir4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce(SiIr)2 by Materials Project

CeIr2Si2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Ce is bonded in a 4-coordinate geometry to eight Ir and eight Si atoms. There are four shorter (3.16 Å) and four longer (3.29 Å) Ce–Ir bond lengths. There are four shorter (3.19 Å) and four longer (3.20 Å) Ce–Si bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Ce and five Si atoms. There are one shorter (2.41 Å) and four longer (2.43 Å) Ir–Si bond lengths. In the second Ir site, Ir is bonded to four equivalent Ce and four equivalent Si atoms to form a mixture of distorted edge and face-sharing IrCe4Si4 tetrahedra. All Ir–Si bond lengths are 2.45 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to four equivalent Ce and five Ir atoms. In the second Si site, Si is bonded in a 4-coordinate geometry to four equivalent Ce and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(SiIr)2 by Materials Project

Np(IrSi)2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Np is bonded in a 4-coordinate geometry to eight Ir and eight Si atoms. There are four shorter (3.13 Å) and four longer (3.29 Å) Np–Ir bond lengths. There are four shorter (3.16 Å) and four longer (3.18 Å) Np–Si bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded to four equivalent Np and four equivalent Si atoms to form distorted IrNp4Si4 tetrahedra that share corners with twelve equivalent SiNp4Ir4 tetrahedra, edges with two equivalent SiNp4Ir4 tetrahedra, edges with four equivalent IrNp4Si4 tetrahedra, and faces with four equivalent IrNp4Si4 tetrahedra. All Ir–Si bond lengths are 2.44 Å. In the second Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Np and five Si atoms. There are one shorter (2.38 Å) and four longer (2.43 Å) Ir–Si bond lengths. There are two inequivalent Si sites. In the first Si site, Si is bonded to four equivalent Np and four equivalent Ir atoms to form distorted SiNp4Ir4 tetrahedra that share corners with twelve equivalent IrNp4Si4 tetrahedra, edges with two equivalent IrNp4Si4 tetrahedra, edges with four equivalent SiNp4Ir4 tetrahedra, and faces with four equivalent SiNp4Ir4 tetrahedra. In the second Si site, Si is bonded in a 9-coordinate geometry to four equivalent Np and five Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(SiIr)2 by Materials Project

UIr2Si2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight Ir and eight Si atoms. There are four shorter (3.11 Å) and four longer (3.25 Å) U–Ir bond lengths. There are four shorter (3.14 Å) and four longer (3.17 Å) U–Si bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent U and five Si atoms. There are one shorter (2.35 Å) and four longer (2.41 Å) Ir–Si bond lengths. In the second Ir site, Ir is bonded to four equivalent U and four equivalent Si atoms to form distorted IrU4Si4 tetrahedra that share corners with twelve equivalent SiU4Ir4 tetrahedra, edges with two equivalent SiU4Ir4 tetrahedra, edges with four equivalent IrU4Si4 tetrahedra, and faces with four equivalent IrU4Si4 tetrahedra. All Ir–Si bond lengths are 2.44 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to four equivalent U and five Ir atoms. In the second Si site, Si is bonded to four equivalent U and four equivalent Ir atoms to form distorted SiU4Ir4 tetrahedra that share corners with twelve equivalent IrU4Si4 tetrahedra, edges with two equivalent IrU4Si4 tetrahedra, edges with four equivalent SiU4Ir4 tetrahedra, and faces with four equivalent SiU4Ir4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sn4B3Ir7 by Materials Project

Ir7B3Sn4 crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional. there are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 2-coordinate geometry to two equivalent B and four Sn atoms. Both Ir–B bond lengths are 2.16 Å. There are a spread of Ir–Sn bond distances ranging from 2.73–2.95 Å. In the second Ir site, Ir is bonded to six equivalent B atoms to form face-sharing IrB6 octahedra. All Ir–B bond lengths are 2.31 Å. B is bonded to six Ir atoms to form a mixture of distorted edge and corner-sharing BIr6 pentagonal pyramids. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 6-coordinate geometry to six equivalent Ir atoms. In the second Sn site, Sn is bonded in a 6-coordinate geometry to six equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho5(Ge5Ir2)2 by Materials Project

Ho5(Ir2Ge5)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are three inequivalent Ho sites. In the first Ho site, Ho is bonded in a 8-coordinate geometry to four equivalent Ir and twelve Ge atoms. All Ho–Ir bond lengths are 3.21 Å. There are eight shorter (3.01 Å) and four longer (3.36 Å) Ho–Ge bond lengths. In the second Ho site, Ho is bonded in a 12-coordinate geometry to four equivalent Ir and eight Ge atoms. All Ho–Ir bond lengths are 3.21 Å. There are a spread of Ho–Ge bond distances ranging from 2.94–3.26 Å. In the third Ho site, Ho is bonded in a 4-coordinate geometry to two equivalent Ir and four Ge atoms. Both Ho–Ir bond lengths are 3.16 Å. There are two shorter (2.78 Å) and two longer (2.82 Å) Ho–Ge bond lengths. Ir is bonded in a 9-coordinate geometry to four Ho and five Ge atoms. There are a spread of Ir–Ge bond distances ranging from 2.46–2.54 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 2-coordinate geometry to three Ho, two equivalent Ir, and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.94 Å. In the second Ge site, Ge is bonded in a 5-coordinate geometry to four Ho and two equivalent Ir atoms. In the third Ge site, Ge is bonded in a 6-coordinate geometry to four Ho and two equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(IrO2)4 by Materials Project

K(IrO2)4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. K1+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.64 Å) and two longer (2.65 Å) K–O bond lengths. There are two inequivalent Ir+3.75+ sites. In the first Ir+3.75+ site, Ir+3.75+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing IrO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Ir–O bond distances ranging from 1.97–2.08 Å. In the second Ir+3.75+ site, Ir+3.75+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing IrO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Ir–O bond distances ranging from 1.99–2.07 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to one K1+ and three equivalent Ir+3.75+ atoms to form a mixture of distorted edge and corner-sharing OKIr3 tetrahedra. In the second O2- site, O2- is bonded in a trigonal planar geometry to three Ir+3.75+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to three Ir+3.75+ atoms. In the fourth O2- site, O2- is bonded to one K1+ and three equivalent Ir+3.75+ atoms to form a mixture of distorted edge and corner-sharing OKIr3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ga2Ir by Materials Project

IrGa2 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 9-coordinate geometry to nine Ga atoms. There are a spread of Ir–Ga bond distances ranging from 2.55–2.75 Å. In the second Ir site, Ir is bonded in a 9-coordinate geometry to nine Ga atoms. There are a spread of Ir–Ga bond distances ranging from 2.48–2.79 Å. There are four inequivalent Ga sites. In the first Ga site, Ga is bonded in a 4-coordinate geometry to four Ir and two equivalent Ga atoms. Both Ga–Ga bond lengths are 2.84 Å. In the second Ga site, Ga is bonded in a 4-coordinate geometry to four Ir atoms. In the third Ga site, Ga is bonded in a 2-coordinate geometry to six Ir and one Ga atom. The Ga–Ga bond length is 2.54 Å. In the fourth Ga site, Ga is bonded in a 1-coordinate geometry to five Ir and five Ga atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y(SiIr)2 by Materials Project

YIr2Si2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Y is bonded in a 8-coordinate geometry to eight Ir and eight Si atoms. There are four shorter (3.15 Å) and four longer (3.26 Å) Y–Ir bond lengths. There are four shorter (3.17 Å) and four longer (3.18 Å) Y–Si bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Y and five Si atoms. There are one shorter (2.37 Å) and four longer (2.43 Å) Ir–Si bond lengths. In the second Ir site, Ir is bonded to four equivalent Y and four equivalent Si atoms to form distorted IrY4Si4 tetrahedra that share corners with twelve equivalent SiY4Ir4 tetrahedra, edges with two equivalent SiY4Ir4 tetrahedra, edges with four equivalent IrY4Si4 tetrahedra, and faces with four equivalent IrY4Si4 tetrahedra. All Ir–Si bond lengths are 2.44 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded to four equivalent Y and four equivalent Ir atoms to form distorted SiY4Ir4 tetrahedra that share corners with twelve equivalent IrY4Si4 tetrahedra, edges with two equivalent IrY4Si4 tetrahedra, edges with four equivalent SiY4Ir4 tetrahedra, and faces with four equivalent SiY4Ir4 tetrahedra. In the second Si site, Si is bonded in a 9-coordinate geometry to four equivalent Y and five Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu(SiIr)2 by Materials Project

Pu(IrSi)2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Pu is bonded in a 8-coordinate geometry to eight Ir and eight Si atoms. There are four shorter (3.13 Å) and four longer (3.24 Å) Pu–Ir bond lengths. There are four shorter (3.14 Å) and four longer (3.18 Å) Pu–Si bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Pu and five Si atoms. There are one shorter (2.37 Å) and four longer (2.42 Å) Ir–Si bond lengths. In the second Ir site, Ir is bonded to four equivalent Pu and four equivalent Si atoms to form distorted IrPu4Si4 tetrahedra that share corners with twelve equivalent SiPu4Ir4 tetrahedra, edges with two equivalent SiPu4Ir4 tetrahedra, edges with four equivalent IrPu4Si4 tetrahedra, and faces with four equivalent IrPu4Si4 tetrahedra. All Ir–Si bond lengths are 2.43 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to four equivalent Pu and five Ir atoms. In the second Si site, Si is bonded to four equivalent Pu and four equivalent Ir atoms to form distorted SiPu4Ir4 tetrahedra that share corners with twelve equivalent IrPu4Si4 tetrahedra, edges with two equivalent IrPu4Si4 tetrahedra, edges with four equivalent SiPu4Ir4 tetrahedra, and faces with four equivalent SiPu4Ir4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce(GeIr)2 by Materials Project

CeIr2Ge2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Ce is bonded in a 12-coordinate geometry to eight Ir and eight Ge atoms. There are four shorter (3.24 Å) and four longer (3.38 Å) Ce–Ir bond lengths. There are four shorter (3.27 Å) and four longer (3.28 Å) Ce–Ge bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 4-coordinate geometry to four equivalent Ce and four equivalent Ge atoms. All Ir–Ge bond lengths are 2.52 Å. In the second Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Ce and five Ge atoms. There are one shorter (2.45 Å) and four longer (2.50 Å) Ir–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to four equivalent Ce and five Ir atoms. In the second Ge site, Ge is bonded in a 4-coordinate geometry to four equivalent Ce and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗