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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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16 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Structure-property relations of oP32-Ge under pressure

The unit-cell parameters, systematic absences, and atomic parameters of the germanium allotrope oP32-Ge show continuous changes up to 6 GPa as shown by single-crystal diffraction analysis. Peak shape and diffuse scattering features remain about unchanged throughout the experiment. Hence, neither the average nor the defect structure behavior offers a structure-property explanation for pressure-induced superconductivity observed at about 2 GPa [1]. Angle dispersive x-ray diffraction reveals a sluggish transformation of oP32-Ge to the Ge-II polymorph, the transition begins around 8 GPa and is complete at 12 GPa, a behavior similar to that of Ge-I. The reconstructive transition was associated with the breakdown of crystals into a powder that was compressed to 32 GPa. Synchrotron infrared absorption measurements up to 8.5 GPa indicate an increase of the band gap of the oP32-Ge prior to its collapse at 8.5 GPa. We suggest that the onset of superconductivity is not associated with a major structural change or that such a change occurs in specific stress and temperature conditions.

Lavina, Barbara↗
DOE OSTI2020

Materials Data on YGe2 by Materials Project

YGe2 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Y is bonded to twelve equivalent Ge atoms to form a mixture of distorted edge and face-sharing YGe12 cuboctahedra. There are eight shorter (3.11 Å) and four longer (3.49 Å) Y–Ge bond lengths. Ge is bonded in a 9-coordinate geometry to six equivalent Y and three equivalent Ge atoms. There are two shorter (2.54 Å) and one longer (2.60 Å) Ge–Ge bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y5Ge4 by Materials Project

Y5Ge4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Y sites. In the first Y site, Y is bonded to six Ge atoms to form corner-sharing YGe6 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Y–Ge bond distances ranging from 2.97–3.12 Å. In the second Y site, Y is bonded in a 6-coordinate geometry to six Ge atoms. There are a spread of Y–Ge bond distances ranging from 2.88–3.05 Å. In the third Y site, Y is bonded in a 7-coordinate geometry to seven Ge atoms. There are a spread of Y–Ge bond distances ranging from 2.99–3.67 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to eight Y and one Ge atom. The Ge–Ge bond length is 2.76 Å. In the second Ge site, Ge is bonded in a 9-coordinate geometry to eight Y and one Ge atom. In the third Ge site, Ge is bonded in a 7-coordinate geometry to eight Y atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y3Ge5 by Materials Project

Y3Ge5 crystallizes in the orthorhombic Fdd2 space group. The structure is three-dimensional. there are two inequivalent Y sites. In the first Y site, Y is bonded in a 8-coordinate geometry to eight Ge atoms. There are a spread of Y–Ge bond distances ranging from 2.98–3.09 Å. In the second Y site, Y is bonded in a 10-coordinate geometry to ten Ge atoms. There are a spread of Y–Ge bond distances ranging from 2.95–3.50 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 4-coordinate geometry to five Y and two equivalent Ge atoms. There are one shorter (2.59 Å) and one longer (2.66 Å) Ge–Ge bond lengths. In the second Ge site, Ge is bonded in a 9-coordinate geometry to six Y and three Ge atoms. The Ge–Ge bond length is 2.60 Å. In the third Ge site, Ge is bonded in a 8-coordinate geometry to six Y and two equivalent Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y3Ge4 by Materials Project

Y3Ge4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Y sites. In the first Y site, Y is bonded in a 5-coordinate geometry to seven Ge atoms. There are a spread of Y–Ge bond distances ranging from 2.92–3.19 Å. In the second Y site, Y is bonded in a 8-coordinate geometry to eight Ge atoms. There are a spread of Y–Ge bond distances ranging from 3.00–3.11 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to seven Y and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.62 Å. In the second Ge site, Ge is bonded in a 4-coordinate geometry to four equivalent Y and four equivalent Ge atoms. All Ge–Ge bond lengths are 2.87 Å. In the third Ge site, Ge is bonded in a 9-coordinate geometry to six Y and three Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y5Ge3 by Materials Project

Y5Ge3 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent Y sites. In the first Y site, Y is bonded in a 3-coordinate geometry to five equivalent Ge atoms. There are a spread of Y–Ge bond distances ranging from 2.93–3.47 Å. In the second Y site, Y is bonded in a 6-coordinate geometry to six equivalent Ge atoms. All Y–Ge bond lengths are 3.08 Å. Ge is bonded in a 9-coordinate geometry to nine Y atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GeI4 by Materials Project

GeI4 is Iron carbide-like structured and crystallizes in the cubic Pa-3 space group. The structure is zero-dimensional and consists of eight germanium tetraiodide molecules. Ge4+ is bonded in a tetrahedral geometry to four I1- atoms. There are one shorter (2.54 Å) and three longer (2.55 Å) Ge–I bond lengths. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a single-bond geometry to one Ge4+ atom. In the second I1- site, I1- is bonded in a single-bond geometry to one Ge4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GeI2 by Materials Project

GeI2 is trigonal omega-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of three GeI2 sheets oriented in the (0, 0, 1) direction. Ge2+ is bonded to six equivalent I1- atoms to form edge-sharing GeI6 octahedra. All Ge–I bond lengths are 3.03 Å. I1- is bonded in a distorted T-shaped geometry to three equivalent Ge2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YGe3 by Materials Project

YGe3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Y is bonded in a 10-coordinate geometry to ten Ge atoms. There are a spread of Y–Ge bond distances ranging from 2.97–3.26 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 7-coordinate geometry to two equivalent Y and five equivalent Ge atoms. There are one shorter (2.51 Å) and four longer (2.83 Å) Ge–Ge bond lengths. In the second Ge site, Ge is bonded in a 7-coordinate geometry to two equivalent Y and five equivalent Ge atoms. In the third Ge site, Ge is bonded in a 8-coordinate geometry to six equivalent Y and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.57 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GeI2 by Materials Project

GeI2 is Molybdenite-like structured and crystallizes in the hexagonal P-6m2 space group. The structure is two-dimensional and consists of one GeI2 sheet oriented in the (0, 0, 1) direction. Ge2+ is bonded to six equivalent I1- atoms to form distorted edge-sharing GeI6 pentagonal pyramids. All Ge–I bond lengths are 3.07 Å. I1- is bonded in a 3-coordinate geometry to three equivalent Ge2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YGe by Materials Project

YGe crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Y is bonded in a 5-coordinate geometry to seven equivalent Ge atoms. There are five shorter (2.98 Å) and two longer (3.23 Å) Y–Ge bond lengths. Ge is bonded in a 5-coordinate geometry to seven equivalent Y and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.70 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GeI2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y2Ge3 by Materials Project

Y2Ge3 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Y is bonded in a 9-coordinate geometry to nine Ge atoms. There are a spread of Y–Ge bond distances ranging from 3.02–3.19 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Y and three equivalent Ge atoms. There are two shorter (2.53 Å) and one longer (2.54 Å) Ge–Ge bond lengths. In the second Ge site, Ge is bonded in a 6-coordinate geometry to six equivalent Y atoms. In the third Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Y and three equivalent Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y11Ge10 by Materials Project

Y11Ge10 is delta Molybdenum Boride-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are four inequivalent Y sites. In the first Y site, Y is bonded in a 8-coordinate geometry to eight Ge atoms. There are four shorter (3.22 Å) and four longer (3.27 Å) Y–Ge bond lengths. In the second Y site, Y is bonded in a 7-coordinate geometry to seven Ge atoms. There are a spread of Y–Ge bond distances ranging from 2.80–3.47 Å. In the third Y site, Y is bonded in a 7-coordinate geometry to seven Ge atoms. There are a spread of Y–Ge bond distances ranging from 2.93–3.10 Å. In the fourth Y site, Y is bonded to seven Ge atoms to form a mixture of distorted corner, edge, and face-sharing YGe7 pentagonal bipyramids. There are a spread of Y–Ge bond distances ranging from 2.89–3.35 Å. There are five inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to eight Y and one Ge atom. The Ge–Ge bond length is 2.58 Å. In the second Ge site, Ge is bonded in a 9-coordinate geometry to eight Y atoms. In the third Ge site, Ge is bonded in a 9-coordinate geometry to seven Y and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.62 Å. In the fourth Ge site, Ge is bonded in a 8-coordinate geometry to eight Y atoms. In the fifth Ge site, Ge is bonded in a 2-coordinate geometry to eight Y atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y3Ge by Materials Project

Y3Ge is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Y sites. In the first Y site, Y is bonded to eight Y and four equivalent Ge atoms to form distorted YY8Ge4 cuboctahedra that share corners with twelve equivalent YY8Ge4 cuboctahedra, edges with eight equivalent YY8Ge4 cuboctahedra, edges with eight equivalent GeY12 cuboctahedra, faces with four equivalent GeY12 cuboctahedra, and faces with ten equivalent YY8Ge4 cuboctahedra. There are four shorter (3.20 Å) and four longer (3.45 Å) Y–Y bond lengths. All Y–Ge bond lengths are 3.45 Å. In the second Y site, Y is bonded in a square co-planar geometry to eight equivalent Y and four equivalent Ge atoms. All Y–Ge bond lengths are 3.20 Å. Ge is bonded to twelve Y atoms to form GeY12 cuboctahedra that share corners with four equivalent GeY12 cuboctahedra, edges with eight equivalent GeY12 cuboctahedra, edges with sixteen equivalent YY8Ge4 cuboctahedra, faces with four equivalent GeY12 cuboctahedra, and faces with eight equivalent YY8Ge4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y3Ge by Materials Project

Y3Ge is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Y is bonded in a distorted see-saw-like geometry to four equivalent Ge atoms. There are two shorter (3.24 Å) and two longer (3.36 Å) Y–Ge bond lengths. Ge is bonded to twelve equivalent Y atoms to form a mixture of face and corner-sharing GeY12 cuboctahedra.

36 MATERIALS SCIENCE↗