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At least 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Cr6C3N by Materials Project

Cr6C3N crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Cr+2.50+ sites. In the first Cr+2.50+ site, Cr+2.50+ is bonded to three C4- and one N3- atom to form corner-sharing CrC3N tetrahedra. All Cr–C bond lengths are 1.97 Å. The Cr–N bond length is 1.93 Å. In the second Cr+2.50+ site, Cr+2.50+ is bonded in a 5-coordinate geometry to five C4- atoms. There are a spread of Cr–C bond distances ranging from 1.98–2.36 Å. In the third Cr+2.50+ site, Cr+2.50+ is bonded in a 4-coordinate geometry to three equivalent C4- and two equivalent N3- atoms. There are two shorter (2.09 Å) and one longer (2.46 Å) Cr–C bond lengths. Both Cr–N bond lengths are 2.02 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to six Cr+2.50+ atoms to form CCr6 octahedra that share corners with two equivalent NCr6 octahedra and edges with two equivalent CCr6 octahedra. The corner-sharing octahedral tilt angles are 55°. In the second C4- site, C4- is bonded in a 8-coordinate geometry to eight Cr+2.50+ atoms. N3- is bonded to six Cr+2.50+ atoms to form NCr6 octahedra that share corners with two equivalent CCr6 octahedra and edges with two equivalent NCr6 octahedra. The corner-sharing octahedral tilt angles are 55°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U4Cr7Si by Materials Project

U4Cr7Si crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are two inequivalent U sites. In the first U site, U is bonded in a 12-coordinate geometry to four U and twelve Cr atoms. There are one shorter (2.98 Å) and three longer (3.13 Å) U–U bond lengths. There are a spread of U–Cr bond distances ranging from 2.94–3.01 Å. In the second U site, U is bonded in a 12-coordinate geometry to four U, nine equivalent Cr, and three equivalent Si atoms. All U–U bond lengths are 3.11 Å. There are six shorter (2.93 Å) and three longer (2.96 Å) U–Cr bond lengths. All U–Si bond lengths are 2.97 Å. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded to six U, five Cr, and one Si atom to form distorted CrU6Cr5Si cuboctahedra that share corners with two equivalent SiU6Cr6 cuboctahedra, corners with sixteen CrU6Cr5Si cuboctahedra, edges with six equivalent CrU6Cr5Si cuboctahedra, faces with three equivalent SiU6Cr6 cuboctahedra, and faces with fifteen CrU6Cr5Si cuboctahedra. There are a spread of Cr–Cr bond distances ranging from 2.48–2.56 Å. The Cr–Si bond length is 2.52 Å. In the second Cr site, Cr is bonded to six equivalent U and six equivalent Cr atoms to form CrU6Cr6 cuboctahedra that share corners with twelve equivalent CrU6Cr5Si cuboctahedra, edges with six equivalent CrU6Cr6 cuboctahedra, faces with two equivalent SiU6Cr6 cuboctahedra, and faces with eighteen equivalent CrU6Cr5Si cuboctahedra. Si is bonded to six equivalent U and six equivalent Cr atoms to form SiU6Cr6 cuboctahedra that share corners with twelve equivalent CrU6Cr5Si cuboctahedra, edges with six equivalent SiU6Cr6 cuboctahedra, and faces with twenty CrU6Cr6 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Development of Chromium and Sulfur Getter for Solid Oxide Fuel Cell (SOFC) System

Under the “real world” SOFC operating conditions, gaseous Cr and S species coexist in air stream. The combined Cr and S effect on the electrochemical poisoning of candidate LSM and LSCF electrodes has been investigated. Electrochemical and structural analysis revealed that the combined Cr and S interactions with the LSCF electrode remains significantly different from those of the individual Cr and S interactions. S reacts with the surface SrO accompanied by morphological changes whereas the hexavalent gaseous Cr species mainly deposit at the LSCF/GDC interface as is the case with Cr-only poisoning. For LSM electrode, the combined interactions of Cr and S remains similar to the sum of individual Cr and S effects as SO 2 reacts with Sr-rich regions of the bulk LSM, while Cr deposits at the electrochemically active sites. The use of getter, consisting of alkaline earth and transition metal oxides, has been proposed as a cost-effective approach to mitigate electrode poisoning. SrMnO 3 (SMO) is suggested as a robust getter material for the co-capture of airborne gaseous S and Cr species entering high-temperature electrochemical systems. The honeycomb getter forms, covered with SMO nanoparticles, were fabricated using dip coating. The SMO getter successfully maintained the electrochemical activity of LSM under the presence of gaseous Cr and S species, validating the efficacy of the getter. Post-test characterization revealed that the absorption of S and Cr contaminants led to the elongation of granular SMO particles, forming SrO nanorods and SrCrO 4 whiskers leaving Mn oxides underneath where inward-migrating Cr reside, indicating the high mutual affinity of Sr and Mn. The growth of reaction products during the long term exposure favors continued absorption of incoming S and Cr contaminants. The Mn 2 O 9 dimers, existing on the surface, are considered to help absorb S and Cr impurities, along with the Sr-terminated surface. The SMO getter also displays robust stability in humid environments at high temperatures without phase transformation or hydrolysis, fulfilling the requirement for operation in high-temperature electrochemical systems.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2020

Chemical-Biological Cyclic Process for Hexavalent Chromium Reduction to Trivalent Chromium in Aqueous Medium - 20224

Conventional treatment of chromium contamination focuses on immobilization of the highly toxic and water-soluble form Cr(VI), by reducing it to the relatively less toxic and less mobile trivalent form, Cr(III), using reducing compounds like ferrous sulfate or ferrous iron, Fe(II). The Cr(VI) also respond to biodegradation and subsequent reduction. During the reduction reaction, Fe(II) is oxidized to ferric, Fe(III), which, being at the highest oxidation state, has no ability to reduce Cr(VI), and therefore remediation process terminates. The good news is that metal-reducing bacteria, S. oneidensis MR-1, can regenerate Fe(II) from Fe(III) with the help of an organic electron donor in an appropriate bacterial media. Thus, in the Cr(VI) chemical remediation process, Fe(II) to Fe(III) conversion is reversed by the biological process, regenerating Fe(II) and the Cr(VI) chemical reduction process continues in a cyclic fashion. This study presents the results of regeneration of Fe(II) from fresh Fe(III) as well as from the reaction products of Cr(VI) and Fe(II). Both fresh Fe(III) and reaction product Fe(III) exhibited the same reduction behavior. Fe(II) production increased with the increase of initial concentration of Fe(III), resulting in 87.5% Fe(II) regeneration. The extent of Fe(III) reduction (Fe(II)t/Fe(III)0.hour) was 21 times higher than the extent of Cr(VI) reduction (Cr(VI)t/Cr(VI)0.hour) by S. oneidensis MR-1. In a cyclic process of sequential Cr(VI) addition, the amount of Fe(II) regeneration decreased with the increase in cycle number, a fixed quantity of starting S. oneidensis MR-1 could regenerate Fe(II) at least five times in a ten-hour period. More importantly, regenerated Fe(II) instantly reduced Cr(VI) to Cr(III). So, Fe(II) regeneration with metal-reducing bacteria has a good potential for application in groundwater and wastewater remediation in reducing Cr(VI) to Cr(III). As a comparison of chemical to biological transformation, chemical transformation of Cr(VI) by Fe(II) was almost 600 times greater than that of biological transformation. Therefore a chemical-biological cyclic process offers potential applications for remediation of groundwater and hexavalent chromium contaminated waste sites. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Materials Data on Cr4(PO4)3 by Materials Project

Cr4(PO4)3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Cr+2.25+ sites. In the first Cr+2.25+ site, Cr+2.25+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cr–O bond distances ranging from 1.97–2.12 Å. In the second Cr+2.25+ site, Cr+2.25+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cr–O bond distances ranging from 1.97–2.81 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is three shorter (1.56 Å) and one longer (1.57 Å) P–O bond length. In the second P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr+2.25+ and one P5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Cr+2.25+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to two equivalent Cr+2.25+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.25+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to two equivalent Cr+2.25+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Cr+2.25+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr+2.25+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr2Cr2F3 by Materials Project

Zr2Cr2F3 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are three inequivalent Zr sites. In the first Zr site, Zr is bonded in a distorted bent 150 degrees geometry to two F atoms. There are one shorter (2.12 Å) and one longer (2.14 Å) Zr–F bond lengths. In the second Zr site, Zr is bonded in a 3-coordinate geometry to three F atoms. There are a spread of Zr–F bond distances ranging from 2.10–2.36 Å. In the third Zr site, Zr is bonded in a 3-coordinate geometry to one Cr and three F atoms. The Zr–Cr bond length is 2.83 Å. There are one shorter (2.24 Å) and two longer (2.45 Å) Zr–F bond lengths. There are three inequivalent Cr sites. In the first Cr site, Cr is bonded in a linear geometry to two F atoms. There are one shorter (2.00 Å) and one longer (2.06 Å) Cr–F bond lengths. In the second Cr site, Cr is bonded in a distorted single-bond geometry to one F atom. The Cr–F bond length is 2.14 Å. In the third Cr site, Cr is bonded in a distorted single-bond geometry to one Zr atom. There are four inequivalent F sites. In the first F site, F is bonded in a 3-coordinate geometry to three Zr atoms. In the second F site, F is bonded in a distorted bent 150 degrees geometry to one Zr and one Cr atom. In the third F site, F is bonded in a distorted trigonal non-coplanar geometry to two Zr and one Cr atom. In the fourth F site, F is bonded in a distorted trigonal planar geometry to two Zr and one Cr atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr6PbO18 by Materials Project

Cr6PbO18 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Cr+5.67+ sites. In the first Cr+5.67+ site, Cr+5.67+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six CrO6 octahedra and a faceface with one PbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of Cr–O bond distances ranging from 1.80–1.92 Å. In the second Cr+5.67+ site, Cr+5.67+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six CrO6 octahedra and faces with two equivalent PbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–5°. There is two shorter (1.84 Å) and four longer (1.85 Å) Cr–O bond length. Pb2+ is bonded to twelve O2- atoms to form PbO12 cuboctahedra that share faces with eight CrO6 octahedra. There are six shorter (2.57 Å) and six longer (2.58 Å) Pb–O bond lengths. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Cr+5.67+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to two Cr+5.67+ and one Pb2+ atom. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Cr+5.67+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to two Cr+5.67+ and one Pb2+ atom. In the fifth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Cr+5.67+ and one Pb2+ atom. In the sixth O2- site, O2- is bonded in a linear geometry to two equivalent Cr+5.67+ and one Pb2+ atom. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent Cr+5.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiCr4O12 by Materials Project

LiCr4O12 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. Li1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Li–O bond distances ranging from 2.36–2.42 Å. There are two inequivalent Cr+5.75+ sites. In the first Cr+5.75+ site, Cr+5.75+ is bonded to four O2- atoms to form corner-sharing CrO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.60–1.77 Å. In the second Cr+5.75+ site, Cr+5.75+ is bonded to four O2- atoms to form corner-sharing CrO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.61–1.82 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Li1+ and one Cr+5.75+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Li1+ and one Cr+5.75+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Cr+5.75+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Li1+ and one Cr+5.75+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Li1+ and one Cr+5.75+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Cr+5.75+ atoms. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Cr+5.75+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaCr4O12 by Materials Project

NaCr4O12 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.50–2.59 Å. There are two inequivalent Cr+5.75+ sites. In the first Cr+5.75+ site, Cr+5.75+ is bonded to four O2- atoms to form corner-sharing CrO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.60–1.78 Å. In the second Cr+5.75+ site, Cr+5.75+ is bonded to four O2- atoms to form corner-sharing CrO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.61–1.83 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one Cr+5.75+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one Cr+5.75+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Cr+5.75+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one Cr+5.75+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+ and one Cr+5.75+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Cr+5.75+ atoms. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Cr+5.75+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr3Ni by Materials Project

Cr3Ni is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Cr sites. In the first Cr site, Cr is bonded to eight equivalent Cr and four equivalent Ni atoms to form CrCr8Ni4 cuboctahedra that share corners with four equivalent CrCr8Ni4 cuboctahedra, corners with eight equivalent NiCr12 cuboctahedra, edges with twenty-four CrCr8Ni4 cuboctahedra, faces with six equivalent NiCr12 cuboctahedra, and faces with twelve CrCr8Ni4 cuboctahedra. All Cr–Cr bond lengths are 2.53 Å. All Cr–Ni bond lengths are 2.54 Å. In the second Cr site, Cr is bonded to eight Cr and four equivalent Ni atoms to form CrCr8Ni4 cuboctahedra that share corners with twelve equivalent CrCr8Ni4 cuboctahedra, edges with eight equivalent NiCr12 cuboctahedra, edges with sixteen CrCr8Ni4 cuboctahedra, faces with four equivalent NiCr12 cuboctahedra, and faces with fourteen CrCr8Ni4 cuboctahedra. All Cr–Cr bond lengths are 2.54 Å. All Cr–Ni bond lengths are 2.53 Å. Ni is bonded to twelve Cr atoms to form NiCr12 cuboctahedra that share corners with four equivalent NiCr12 cuboctahedra, corners with eight equivalent CrCr8Ni4 cuboctahedra, edges with eight equivalent NiCr12 cuboctahedra, edges with sixteen equivalent CrCr8Ni4 cuboctahedra, faces with four equivalent NiCr12 cuboctahedra, and faces with fourteen CrCr8Ni4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiCr2P2O9 by Materials Project

LiCr2P2O9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Li1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.36 Å. There are two inequivalent Cr+3.50+ sites. In the first Cr+3.50+ site, Cr+3.50+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent CrO6 octahedra, corners with three equivalent PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of Cr–O bond distances ranging from 1.85–2.03 Å. In the second Cr+3.50+ site, Cr+3.50+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent CrO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent CrO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of Cr–O bond distances ranging from 2.00–2.04 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with five CrO6 octahedra. The corner-sharing octahedra tilt angles range from 3–53°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CrO6 octahedra and an edgeedge with one CrO6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of P–O bond distances ranging from 1.55–1.57 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Cr+3.50+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Cr+3.50+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Cr+3.50+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Cr+3.50+ and one P5+ atom. In the fifth O2- site, O2- is bonded in an L-shaped geometry to one Cr+3.50+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+, one Cr+3.50+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Cr+3.50+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr3Fe by Materials Project

Cr3Fe is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Cr sites. In the first Cr site, Cr is bonded to eight equivalent Cr and four equivalent Fe atoms to form CrCr8Fe4 cuboctahedra that share corners with four equivalent CrCr8Fe4 cuboctahedra, corners with eight equivalent FeCr12 cuboctahedra, edges with twenty-four CrCr8Fe4 cuboctahedra, faces with six equivalent FeCr12 cuboctahedra, and faces with twelve CrCr8Fe4 cuboctahedra. All Cr–Cr bond lengths are 2.55 Å. All Cr–Fe bond lengths are 2.48 Å. In the second Cr site, Cr is bonded to eight Cr and four equivalent Fe atoms to form CrCr8Fe4 cuboctahedra that share corners with twelve equivalent CrCr8Fe4 cuboctahedra, edges with eight equivalent FeCr12 cuboctahedra, edges with sixteen CrCr8Fe4 cuboctahedra, faces with four equivalent FeCr12 cuboctahedra, and faces with fourteen CrCr8Fe4 cuboctahedra. All Cr–Cr bond lengths are 2.48 Å. All Cr–Fe bond lengths are 2.55 Å. Fe is bonded to twelve Cr atoms to form FeCr12 cuboctahedra that share corners with four equivalent FeCr12 cuboctahedra, corners with eight equivalent CrCr8Fe4 cuboctahedra, edges with eight equivalent FeCr12 cuboctahedra, edges with sixteen equivalent CrCr8Fe4 cuboctahedra, faces with four equivalent FeCr12 cuboctahedra, and faces with fourteen CrCr8Fe4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaCr2P2O9 by Materials Project

NaCr2P2O9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.34–2.88 Å. There are two inequivalent Cr+3.50+ sites. In the first Cr+3.50+ site, Cr+3.50+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent CrO6 octahedra, corners with three equivalent PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of Cr–O bond distances ranging from 1.83–2.05 Å. In the second Cr+3.50+ site, Cr+3.50+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent CrO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent CrO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of Cr–O bond distances ranging from 1.99–2.06 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with five CrO6 octahedra. The corner-sharing octahedra tilt angles range from 2–55°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CrO6 octahedra and an edgeedge with one CrO6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of P–O bond distances ranging from 1.55–1.57 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Cr+3.50+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Cr+3.50+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr+3.50+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Cr+3.50+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cr+3.50+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Cr+3.50+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Cr+3.50+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy6Al43Cr4 by Materials Project

Dy6Cr4Al43 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. Dy is bonded in a 6-coordinate geometry to one Dy, one Cr, and fifteen Al atoms. The Dy–Dy bond length is 3.40 Å. The Dy–Cr bond length is 3.49 Å. There are a spread of Dy–Al bond distances ranging from 3.04–3.48 Å. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded in a 10-coordinate geometry to two equivalent Dy and ten Al atoms. There are a spread of Cr–Al bond distances ranging from 2.57–2.67 Å. In the second Cr site, Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share edges with six equivalent AlAl10Cr2 cuboctahedra. There are six shorter (2.64 Å) and six longer (2.81 Å) Cr–Al bond lengths. There are seven inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to one Dy, two Cr, and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.71–2.94 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to four equivalent Dy and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.74–3.08 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Dy, one Cr, and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.73–3.04 Å. In the fourth Al site, Al is bonded to two equivalent Cr and ten Al atoms to form distorted AlAl10Cr2 cuboctahedra that share corners with four equivalent AlDy3Al9 cuboctahedra, edges with two equivalent CrAl12 cuboctahedra, and faces with two equivalent AlAl10Cr2 cuboctahedra. Both Al–Al bond lengths are 2.76 Å. In the fifth Al site, Al is bonded in a 12-coordinate geometry to two equivalent Dy, one Cr, and nine Al atoms. Both Al–Al bond lengths are 2.96 Å. In the sixth Al site, Al is bonded to three equivalent Dy and nine Al atoms to form a mixture of face and corner-sharing AlDy3Al9 cuboctahedra. All Al–Al bond lengths are 2.81 Å. In the seventh Al site, Al is bonded in a 10-coordinate geometry to two equivalent Dy, one Cr, and seven Al atoms. The Al–Al bond length is 2.74 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho6Al43Cr4 by Materials Project

Ho6Cr4Al43 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. Ho is bonded in a 6-coordinate geometry to one Ho, one Cr, and fifteen Al atoms. The Ho–Ho bond length is 3.39 Å. The Ho–Cr bond length is 3.48 Å. There are a spread of Ho–Al bond distances ranging from 3.03–3.46 Å. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded in a 12-coordinate geometry to two equivalent Ho and ten Al atoms. There are a spread of Cr–Al bond distances ranging from 2.56–2.66 Å. In the second Cr site, Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share edges with six equivalent AlAl10Cr2 cuboctahedra. There are six shorter (2.64 Å) and six longer (2.80 Å) Cr–Al bond lengths. There are seven inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to one Ho, two Cr, and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.69–2.93 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to four equivalent Ho and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.72–3.08 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Ho, one Cr, and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.72–3.00 Å. In the fourth Al site, Al is bonded to two equivalent Cr and ten Al atoms to form distorted AlAl10Cr2 cuboctahedra that share corners with four equivalent AlHo3Al9 cuboctahedra, edges with two equivalent CrAl12 cuboctahedra, and faces with two equivalent AlAl10Cr2 cuboctahedra. Both Al–Al bond lengths are 2.74 Å. In the fifth Al site, Al is bonded in a 12-coordinate geometry to two equivalent Ho, one Cr, and nine Al atoms. Both Al–Al bond lengths are 2.95 Å. In the sixth Al site, Al is bonded to three equivalent Ho and nine Al atoms to form a mixture of face and corner-sharing AlHo3Al9 cuboctahedra. All Al–Al bond lengths are 2.80 Å. In the seventh Al site, Al is bonded in a 10-coordinate geometry to two equivalent Ho, one Cr, and seven Al atoms. The Al–Al bond length is 2.74 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrCr2O10 by Materials Project

SrCr2O10 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Sr is bonded in a 6-coordinate geometry to ten O atoms. There are a spread of Sr–O bond distances ranging from 2.49–3.31 Å. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded to four O atoms to form corner-sharing CrO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.63–1.77 Å. In the second Cr site, Cr is bonded to four O atoms to form corner-sharing CrO4 tetrahedra. There is three shorter (1.64 Å) and one longer (1.77 Å) Cr–O bond length. There are ten inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one Sr and one Cr atom. In the second O site, O is bonded in a distorted bent 150 degrees geometry to one Sr and one Cr atom. In the third O site, O is bonded in a bent 120 degrees geometry to one Sr and one O atom. The O–O bond length is 1.23 Å. In the fourth O site, O is bonded in a single-bond geometry to one Cr atom. In the fifth O site, O is bonded in a single-bond geometry to two equivalent Sr atoms. In the sixth O site, O is bonded in a distorted single-bond geometry to one Sr and one Cr atom. In the seventh O site, O is bonded in a distorted single-bond geometry to two equivalent Sr and one O atom. The O–O bond length is 1.24 Å. In the eighth O site, O is bonded in a bent 150 degrees geometry to one Sr and one Cr atom. In the ninth O site, O is bonded in a bent 150 degrees geometry to two Cr atoms. In the tenth O site, O is bonded in a bent 150 degrees geometry to one Sr and one Cr atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb2(CrSi)3 by Materials Project

Nb2(CrSi)3 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are three inequivalent Nb2+ sites. In the first Nb2+ site, Nb2+ is bonded to five Si4- atoms to form NbSi5 trigonal bipyramids that share corners with two equivalent NbSi5 trigonal bipyramids, corners with six equivalent CrSi5 trigonal bipyramids, and edges with six NbSi5 trigonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.62–2.74 Å. In the second Nb2+ site, Nb2+ is bonded to five Si4- atoms to form distorted NbSi5 trigonal bipyramids that share corners with eight NbSi5 trigonal bipyramids, edges with two equivalent NbSi5 trigonal bipyramids, and edges with four equivalent CrSi5 trigonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.54–2.72 Å. In the third Nb2+ site, Nb2+ is bonded to five Si4- atoms to form NbSi5 trigonal bipyramids that share corners with eight NbSi5 trigonal bipyramids, edges with two equivalent NbSi5 trigonal bipyramids, and edges with four equivalent CrSi5 trigonal bipyramids. There are a spread of Nb–Si bond distances ranging from 2.58–2.71 Å. There are two inequivalent Cr+2.67+ sites. In the first Cr+2.67+ site, Cr+2.67+ is bonded in a 8-coordinate geometry to two equivalent Cr+2.67+ and six Si4- atoms. There are one shorter (2.41 Å) and one longer (2.45 Å) Cr–Cr bond lengths. There are a spread of Cr–Si bond distances ranging from 2.48–2.54 Å. In the second Cr+2.67+ site, Cr+2.67+ is bonded to five Si4- atoms to form distorted CrSi5 trigonal bipyramids that share corners with three equivalent NbSi5 trigonal bipyramids, corners with five equivalent CrSi5 trigonal bipyramids, and edges with six NbSi5 trigonal bipyramids. There are a spread of Cr–Si bond distances ranging from 2.47–2.68 Å. There are four inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to three Nb2+ and six Cr+2.67+ atoms. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to three Nb2+ and six Cr+2.67+ atoms. In the third Si4- site, Si4- is bonded in a 9-coordinate geometry to three Nb2+ and six Cr+2.67+ atoms. In the fourth Si4- site, Si4- is bonded in a 9-coordinate geometry to five Nb2+ and four equivalent Cr+2.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm6Al43Cr4 by Materials Project

Tm6Cr4Al43 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. Tm is bonded in a 6-coordinate geometry to one Tm, one Cr, and fifteen Al atoms. The Tm–Tm bond length is 3.39 Å. The Tm–Cr bond length is 3.47 Å. There are a spread of Tm–Al bond distances ranging from 3.03–3.46 Å. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded in a 12-coordinate geometry to two equivalent Tm and ten Al atoms. There are a spread of Cr–Al bond distances ranging from 2.56–2.65 Å. In the second Cr site, Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share edges with six equivalent AlAl10Cr2 cuboctahedra. There are six shorter (2.64 Å) and six longer (2.81 Å) Cr–Al bond lengths. There are seven inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to one Tm, two Cr, and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.70–2.93 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to four equivalent Tm and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.72–3.06 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Tm, one Cr, and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.72–3.01 Å. In the fourth Al site, Al is bonded to two equivalent Cr and ten Al atoms to form distorted AlAl10Cr2 cuboctahedra that share corners with four equivalent AlTm3Al9 cuboctahedra, edges with two equivalent CrAl12 cuboctahedra, and faces with two equivalent AlAl10Cr2 cuboctahedra. Both Al–Al bond lengths are 2.75 Å. In the fifth Al site, Al is bonded in a 12-coordinate geometry to two equivalent Tm, one Cr, and nine Al atoms. Both Al–Al bond lengths are 2.95 Å. In the sixth Al site, Al is bonded to three equivalent Tm and nine Al atoms to form a mixture of face and corner-sharing AlTm3Al9 cuboctahedra. All Al–Al bond lengths are 2.80 Å. In the seventh Al site, Al is bonded in a 10-coordinate geometry to two equivalent Tm, one Cr, and seven Al atoms. The Al–Al bond length is 2.74 Å.

36 MATERIALS SCIENCE↗