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At least 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on H7BrO3 by Materials Project

H2OH7O3H5(OBr)2 crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one water molecule, one H5(OBr)2 cluster, and one H7O3 cluster. In the H5(OBr)2 cluster, there are five inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.01 Å. The H–Br bond length is 2.10 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.10 Å) and one longer (1.35 Å) H–O bond length. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.01 Å. The H–Br bond length is 2.09 Å. In the fifth H1+ site, H1+ is bonded in a distorted single-bond geometry to one O2- atom. The H–O bond length is 1.01 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. In the second O2- site, O2- is bonded in a trigonal planar geometry to three H1+ atoms. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one H1+ atom. In the second Br1- site, Br1- is bonded in a distorted single-bond geometry to one H1+ atom. In the H7O3 cluster, there are seven inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the sixth H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.59 Å) H–O bond length. In the seventh H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.12 Å) and one longer (1.33 Å) H–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three H1+ atoms. In the third O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on S5N2O2F by Materials Project

N2S3S2O2F crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of eight N2S3 clusters and eight S2O2F clusters. In each N2S3 cluster, there are two inequivalent N3+ sites. In the first N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S+0.20- atoms. There is one shorter (1.59 Å) and one longer (1.60 Å) N–S bond length. In the second N3+ site, N3+ is bonded in a bent 120 degrees geometry to two S+0.20- atoms. There is one shorter (1.58 Å) and one longer (1.59 Å) N–S bond length. There are three inequivalent S+0.20- sites. In the first S+0.20- site, S+0.20- is bonded in a water-like geometry to two N3+ atoms. In the second S+0.20- site, S+0.20- is bonded in a distorted single-bond geometry to one N3+ atom. In the third S+0.20- site, S+0.20- is bonded in a 1-coordinate geometry to one N3+ atom. In each S2O2F cluster, there are two inequivalent S+0.20- sites. In the first S+0.20- site, S+0.20- is bonded in a distorted trigonal non-coplanar geometry to one S+0.20-, two O2-, and one F1- atom. The S–S bond length is 1.93 Å. Both S–O bond lengths are 1.45 Å. The S–F bond length is 1.76 Å. In the second S+0.20- site, S+0.20- is bonded in a distorted single-bond geometry to one S+0.20- atom. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S+0.20- atom. In the second O2- site, O2- is bonded in a single-bond geometry to one S+0.20- atom. F1- is bonded in a distorted single-bond geometry to one S+0.20- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Probing Heterogeneity in Bovine Enamel Composition through Nanoscale Chemical Imaging using Atom Probe Tomography

Objective: The aim of this study was to determine the heterogeneity in chemical composition of bovine enamel using atom probe tomography, and thereby evaluate the suitability of bovine enamel as a substitute for human enamel in in vitro dental research. Design: Enamel samples from extracted bovine incisor teeth were first sectioned using a diamond saw and then milled into needle-like samples (<100 nm diameter) by focused ion beam (FIB) coupled with a scanning electron microscope (SEM). The samples were then analyzed in the atom probe to acquire three-dimensional (3D) images and quantify the atomic chemistry and distribution in bovine enamel. Results: For the first time, the atomic-level composition and clustering of major constituents and impurities within bovine enamel were determined and imaged. We discovered that the chemical composition of bovine enamel is spatially inhomogeneous at the atomic scale. The average bulk Ca/P ratio, ~1.4, was in agreement with previously reported literature values from alternative conventional methods. When assessed locally at the atomic scale, the Ca/P ratio varied between 1.1 and 2.03. We also discovered that the Mg impurities were significantly segregated throughout the enamel, and such clustering influenced the variation of Ca/P ratios. The increase in Mg concentrations, near the Mg clusters, correlated with increased Ca and decreased P concentrations. Conclusion: In conclusion, the presented findings of variability in local composition should be taken into account when interpreting dental research results from bovine enamel.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Materials Data on B3H5 by Materials Project

(BH2)3(BH)2B4H7 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of eight boranediylradical molecules, four B4H7 clusters, and four BH2 clusters. In each B4H7 cluster, there are four inequivalent B1- sites. In the first B1- site, B1- is bonded in a distorted trigonal non-coplanar geometry to three H+0.60+ atoms. There are a spread of B–H bond distances ranging from 1.19–1.35 Å. In the second B1- site, B1- is bonded in a distorted trigonal non-coplanar geometry to three H+0.60+ atoms. There are a spread of B–H bond distances ranging from 1.19–1.35 Å. In the third B1- site, B1- is bonded in a distorted water-like geometry to two H+0.60+ atoms. There is one shorter (1.19 Å) and one longer (1.33 Å) B–H bond length. In the fourth B1- site, B1- is bonded in a distorted water-like geometry to two H+0.60+ atoms. There is one shorter (1.19 Å) and one longer (1.33 Å) B–H bond length. There are seven inequivalent H+0.60+ sites. In the first H+0.60+ site, H+0.60+ is bonded in an L-shaped geometry to two B1- atoms. In the second H+0.60+ site, H+0.60+ is bonded in a single-bond geometry to one B1- atom. In the third H+0.60+ site, H+0.60+ is bonded in an L-shaped geometry to two B1- atoms. In the fourth H+0.60+ site, H+0.60+ is bonded in an L-shaped geometry to two B1- atoms. In the fifth H+0.60+ site, H+0.60+ is bonded in a single-bond geometry to one B1- atom. In the sixth H+0.60+ site, H+0.60+ is bonded in a single-bond geometry to one B1- atom. In the seventh H+0.60+ site, H+0.60+ is bonded in a single-bond geometry to one B1- atom. In each BH2 cluster, there are three inequivalent B1- sites. In the first B1- site, B1- is bonded in a distorted water-like geometry to two H+0.60+ atoms. There is one shorter (1.19 Å) and one longer (1.28 Å) B–H bond length. In the second B1- site, B1- is bonded in a distorted tetrahedral geometry to four H+0.60+ atoms. There are a spread of B–H bond distances ranging from 1.20–1.40 Å. In the third B1- site, B1- is bonded in a distorted water-like geometry to two H+0.60+ atoms. There is one shorter (1.19 Å) and one longer (1.28 Å) B–H bond length. There are six inequivalent H+0.60+ sites. In the first H+0.60+ site, H+0.60+ is bonded in a single-bond geometry to one B1- atom. In the second H+0.60+ site, H+0.60+ is bonded in a single-bond geometry to one B1- atom. In the third H+0.60+ site, H+0.60+ is bonded in a single-bond geometry to one B1- atom. In the fourth H+0.60+ site, H+0.60+ is bonded in a single-bond geometry to one B1- atom. In the fifth H+0.60+ site, H+0.60+ is bonded in an L-shaped geometry to two B1- atoms. In the sixth H+0.60+ site, H+0.60+ is bonded in an L-shaped geometry to two B1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2B10H9O by Materials Project

K2B4H4OB5H4BH crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four boranediylradical molecules, two B5H4 clusters, and two K2B4H4O clusters. In each B5H4 cluster, there are five inequivalent B sites. In the first B site, B is bonded in a distorted single-bond geometry to one B and one H atom. The B–B bond length is 1.76 Å. The B–H bond length is 1.20 Å. In the second B site, B is bonded in a distorted single-bond geometry to one B and one H atom. The B–B bond length is 1.74 Å. The B–H bond length is 1.20 Å. In the third B site, B is bonded in a distorted single-bond geometry to one B and one H atom. The B–B bond length is 1.75 Å. The B–H bond length is 1.20 Å. In the fourth B site, B is bonded in a distorted single-bond geometry to one B and one H atom. The B–B bond length is 1.75 Å. The B–H bond length is 1.20 Å. In the fifth B site, B is bonded in a 5-coordinate geometry to five B atoms. The B–B bond length is 1.65 Å. There are four inequivalent H sites. In the first H site, H is bonded in a distorted single-bond geometry to one B atom. In the second H site, H is bonded in a distorted single-bond geometry to one B atom. In the third H site, H is bonded in a single-bond geometry to one B atom. In the fourth H site, H is bonded in a single-bond geometry to one B atom. In each K2B4H4O cluster, there are two inequivalent K sites. In the first K site, K is bonded in a 1-coordinate geometry to one O atom. The K–O bond length is 2.66 Å. In the second K site, K is bonded in a 1-coordinate geometry to five H and one O atom. There are a spread of K–H bond distances ranging from 2.67–2.96 Å. The K–O bond length is 2.62 Å. There are four inequivalent B sites. In the first B site, B is bonded in a distorted single-bond geometry to one H atom. The B–H bond length is 1.20 Å. In the second B site, B is bonded in a distorted single-bond geometry to one H atom. The B–H bond length is 1.20 Å. In the third B site, B is bonded in a distorted single-bond geometry to one H atom. The B–H bond length is 1.21 Å. In the fourth B site, B is bonded in a distorted single-bond geometry to one H atom. The B–H bond length is 1.21 Å. There are four inequivalent H sites. In the first H site, H is bonded in a distorted single-bond geometry to one K and one B atom. In the second H site, H is bonded in a distorted single-bond geometry to two equivalent K and one B atom. In the third H site, H is bonded in a distorted single-bond geometry to one K and one B atom. In the fourth H site, H is bonded in a single-bond geometry to one K and one B atom. O is bonded in a bent 120 degrees geometry to two K atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on As12S13 by Materials Project

As(SAs)9As14S17 crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one arsenic molecule, one As14S17 cluster, and one SAs cluster. In the As14S17 cluster, there are fourteen inequivalent As+2.17+ sites. In the first As+2.17+ site, As+2.17+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.19 Å. In the second As+2.17+ site, As+2.17+ is bonded in a trigonal non-coplanar geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.27–2.35 Å. In the third As+2.17+ site, As+2.17+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.34 Å) and one longer (2.36 Å) As–S bond lengths. In the fourth As+2.17+ site, As+2.17+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.28 Å) and one longer (2.62 Å) As–S bond lengths. In the fifth As+2.17+ site, As+2.17+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.24 Å) and one longer (2.39 Å) As–S bond lengths. In the sixth As+2.17+ site, As+2.17+ is bonded in a T-shaped geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.24–2.70 Å. In the seventh As+2.17+ site, As+2.17+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.25 Å. In the eighth As+2.17+ site, As+2.17+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.31 Å) and one longer (2.33 Å) As–S bond lengths. In the ninth As+2.17+ site, As+2.17+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.26 Å. In the tenth As+2.17+ site, As+2.17+ is bonded in a distorted single-bond geometry to one S2- atom. The As–S bond length is 2.45 Å. In the eleventh As+2.17+ site, As+2.17+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.36 Å. In the twelfth As+2.17+ site, As+2.17+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.07–2.97 Å. In the thirteenth As+2.17+ site, As+2.17+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.37 Å. In the fourteenth As+2.17+ site, As+2.17+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.10 Å) and one longer (2.43 Å) As–S bond lengths. There are seventeen inequivalent S2- sites. In the first S2- site, S2- is bonded in a single-bond geometry to one As+2.17+ atom. In the second S2- site, S2- is bonded in a single-bond geometry to one As+2.17+ atom. In the third S2- site, S2- is bonded in a distorted single-bond geometry to one S2- atom. The S–S bond length is 1.98 Å. In the fourth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.17+ and one S2- atom. The S–S bond length is 2.03 Å. In the fifth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.17+ and one S2- atom. In the sixth S2- site, S2- is bonded in a bent 120 degrees geometry to two As+2.17+ atoms. In the seventh S2- site, S2- is bonded in a bent 120 degrees geometry to two As+2.17+ atoms. In the eighth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.17+ and one S2- atom. The S–S bond length is 2.01 Å. In the ninth S2- site, S2- is bonded in a 3-coordinate geometry to two As+2.17+ and one S2- atom. The S–S bond length is 2.07 Å. In the tenth S2- site, S2- is bonded in a distorted single-bond geometry to one As+2.17+ and one S2- atom. In the eleventh S2- site, S2- is bonded in a 1-coordinate geometry to one As+2.17+ and one S2- atom. In the twelfth S2- site, S2- is bonded in a 3-coordinate geometry to three As+2.17+ atoms. In the thirteenth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.17+ and one S2- atom. The S–S bond length is 2.01 Å. In the fourteenth S2- site, S2- is bonded in a distorted L-shaped geometry to two As+2.17+ atoms. In the fifteenth S2- site, S2- is bonded in a 3-coordinate geometry to two As+2.17+ and one S2- atom. In the sixteenth S2- site, S2- is bonded in a 3-coordinate geometry to three As+2.17+ atoms. In the seventeenth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.17+ and one S2- atom. In the SAs cluster, there are nine inequivalent As+2.17+ sites. In the first As+2.17+ site, As+2.17+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.21 Å) and one longer (2.43 Å) As–S bond lengths. In the second As+2.17+ site, As+2.17+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 3.05 Å. In the third As+2.17+ site, As+2.17+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.28 Å. In the fourth As+2.17+ site, As+2.17+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.30 Å. In the fifth As+2.17+ site, As+2.17+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.26 Å) and one longer (2.41 Å) As–S bond lengths. In the sixth As+2.17+ site, As+2.17+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.28 Å) and one longer (2.33 Å) As–S bond lengths. In the seventh As+2.17+ site, As+2.17+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.22 Å. In the eighth As+2.17+ site, As+2.17+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.27 Å) and one longer (2.33 Å) As–S bond lengths. In the ninth As+2.17+ site, As+2.17+ is bonded in a bent 150 degrees geometry to two S2- atoms. There are one shorter (2.41 Å) and one longer (2.58 Å) As–S bond lengths. There are nine inequivalent S2- sites. In the first S2- site, S2- is bonded in an L-shaped geometry to two As+2.17+ atoms. In the second S2- site, S2- is bonded in a 2-coordinate geometry to two As+2.17+ atoms. In the third S2- site, S2- is bonded in a distorted L-shaped geometry to one As+2.17+ and one S2- atom. The S–S bond length is 2.02 Å. In the fourth S2- site, S2- is bonded in a 1-coordinate geometry to two As+2.17+ and one S2- atom. The S–S bond length is 2.06 Å. In the fifth S2- site, S2- is bonded in a water-like geometry to one As+2.17+ and one S2- atom. In the sixth S2- site, S2- is bonded in a distorted trigonal non-coplanar geometry to three As+2.17+ atoms. In the seventh S2- site, S2- is bonded in a distorted water-like geometry to one As+2.17+ and one S2- atom. In the eighth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.17+ and one S2- atom. The S–S bond length is 2.07 Å. In the ninth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.17+ and one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on As8S9 by Materials Project

(As)3(As4S5)2As11S13(SSAs)2 crystallizes in the triclinic P1 space group. The structure is one-dimensional and consists of three arsenic molecules; one As11S13 cluster; one As4S5 cluster; and one SSAs ribbon oriented in the (1, 0, 0) direction. In the As11S13 cluster, there are eleven inequivalent As+2.25+ sites. In the first As+2.25+ site, As+2.25+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.29 Å) and one longer (2.31 Å) As–S bond lengths. In the second As+2.25+ site, As+2.25+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.24 Å) and one longer (2.29 Å) As–S bond lengths. In the third As+2.25+ site, As+2.25+ is bonded in a distorted water-like geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.25–3.01 Å. In the fourth As+2.25+ site, As+2.25+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.36 Å. In the fifth As+2.25+ site, As+2.25+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.29 Å) and one longer (2.31 Å) As–S bond lengths. In the sixth As+2.25+ site, As+2.25+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.31 Å) and one longer (2.32 Å) As–S bond lengths. In the seventh As+2.25+ site, As+2.25+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.27 Å) and one longer (2.42 Å) As–S bond lengths. In the eighth As+2.25+ site, As+2.25+ is bonded in a distorted linear geometry to two S2- atoms. There are one shorter (2.36 Å) and one longer (2.90 Å) As–S bond lengths. In the ninth As+2.25+ site, As+2.25+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.32 Å. In the tenth As+2.25+ site, As+2.25+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.33 Å. In the eleventh As+2.25+ site, As+2.25+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.21 Å. There are thirteen inequivalent S2- sites. In the first S2- site, S2- is bonded in a 2-coordinate geometry to two As+2.25+ atoms. In the second S2- site, S2- is bonded in a distorted bent 120 degrees geometry to two As+2.25+ atoms. In the third S2- site, S2- is bonded in a 2-coordinate geometry to two As+2.25+ atoms. In the fourth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.25+ and one S2- atom. The S–S bond length is 1.99 Å. In the fifth S2- site, S2- is bonded in a distorted L-shaped geometry to one As+2.25+ and one S2- atom. The S–S bond length is 2.06 Å. In the sixth S2- site, S2- is bonded in a 3-coordinate geometry to two As+2.25+ and one S2- atom. In the seventh S2- site, S2- is bonded in a 2-coordinate geometry to one As+2.25+ and one S2- atom. The S–S bond length is 2.01 Å. In the eighth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.25+ and one S2- atom. In the ninth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.25+ and one S2- atom. In the tenth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.25+ and one S2- atom. The S–S bond length is 2.06 Å. In the eleventh S2- site, S2- is bonded in an L-shaped geometry to two As+2.25+ atoms. In the twelfth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.25+ and one S2- atom. In the thirteenth S2- site, S2- is bonded in a 2-coordinate geometry to two As+2.25+ atoms. In the As4S5 cluster, there are eight inequivalent As+2.25+ sites. In the first As+2.25+ site, As+2.25+ is bonded in a distorted T-shaped geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.24–2.44 Å. In the second As+2.25+ site, As+2.25+ is bonded in a 2-coordinate geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.23–2.95 Å. In the third As+2.25+ site, As+2.25+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.12 Å) and one longer (2.42 Å) As–S bond lengths. In the fourth As+2.25+ site, As+2.25+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.99 Å. In the fifth As+2.25+ site, As+2.25+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.29 Å. In the sixth As+2.25+ site, As+2.25+ is bonded in a T-shaped geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.34–2.70 Å. In the seventh As+2.25+ site, As+2.25+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.17 Å) and one longer (2.76 Å) As–S bond lengths. In the eighth As+2.25+ site, As+2.25+ is bonded in a trigonal non-coplanar geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.13–2.56 Å. There are ten inequivalent S2- sites. In the first S2- site, S2- is bonded in a water-like geometry to two As+2.25+ atoms. In the second S2- site, S2- is bonded in a 2-coordinate geometry to three As+2.25+ atoms. In the third S2- site, S2- is bonded in a 3-coordinate geometry to three As+2.25+ atoms. In the fourth S2- site, S2- is bonded in a water-like geometry to two As+2.25+ atoms. In the fifth S2- site, S2- is bonded in a 1-coordinate geometry to one As+2.25+ and one S2- atom. The S–S bond length is 2.06 Å. In the sixth S2- site, S2- is bonded in a single-bond geometry to one As+2.25+ atom. In the seventh S2- site, S2- is bonded in a single-bond geometry to one As+2.25+ atom. In the eighth S2- site, S2- is bonded in a 4-coordinate geometry to two As+2.25+ and one S2- atom. In the ninth S2- site, S2- is bonded in a distorted L-shaped geometry to one As+2.25+ and one S2- atom. The S–S bond length is 2.04 Å. In the tenth S2- site, S2- is bonded in a trigonal non-coplanar geometry to two As+2.25+ and one S2- atom. In the SSAs ribbon, there are two inequivalent As+2.25+ sites. In the first As+2.25+ site, As+2.25+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.28 Å) and one longer (2.31 Å) As–S bond lengths. In the second As+2.25+ site, As+2.25+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.31 Å) and one longer (2.35 Å) As–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a water-like geometry to two As+2.25+ atoms. In the second S2- site, S2- is bonded in a distorted water-like geometry to one As+2.25+ and one S2- atom. The S–S bond length is 2.06 Å. In the third S2- site, S2- is bonded in a distorted water-like geometry to two S2- atoms. The S–S bond length is 2.07 Å. In the fourth S2- site, S2- is bonded in a distorted water-like geometry to one As+2.25+ and one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te7IrBr7 by Materials Project

IrTe(TeBr)3Te3Br4 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two iridium molecules, two tellurium molecules, two Te3Br4 clusters, and two TeBr clusters. In each Te3Br4 cluster, there are three inequivalent Te+0.57+ sites. In the first Te+0.57+ site, Te+0.57+ is bonded in a single-bond geometry to one Br1- atom. The Te–Br bond length is 3.34 Å. In the second Te+0.57+ site, Te+0.57+ is bonded in a single-bond geometry to one Br1- atom. The Te–Br bond length is 3.13 Å. In the third Te+0.57+ site, Te+0.57+ is bonded in a rectangular see-saw-like geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.66–2.94 Å. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted water-like geometry to two Te+0.57+ atoms. In the second Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.57+ atom. In the third Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.57+ atom. In the fourth Br1- site, Br1- is bonded in a 1-coordinate geometry to two Te+0.57+ atoms. In each TeBr cluster, there are three inequivalent Te+0.57+ sites. In the first Te+0.57+ site, Te+0.57+ is bonded in a distorted single-bond geometry to one Br1- atom. The Te–Br bond length is 3.07 Å. In the second Te+0.57+ site, Te+0.57+ is bonded in a distorted single-bond geometry to one Br1- atom. The Te–Br bond length is 3.01 Å. In the third Te+0.57+ site, Te+0.57+ is bonded in a T-shaped geometry to three Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.57–2.82 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in an L-shaped geometry to two Te+0.57+ atoms. In the second Br1- site, Br1- is bonded in a single-bond geometry to one Te+0.57+ atom. In the third Br1- site, Br1- is bonded in a distorted L-shaped geometry to two Te+0.57+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Influence of counterion substitution on the properties of imidazolium-based ionic liquid clusters

Due to their unique physiochemical properties that may be tailored for specific purposes, ionic liquids (ILs) have been investigated for various applications, including chemical separations, catalysis, energy storage, and space propulsion. The different cations and anions comprising ILs may be selected to optimize a range of desired properties, such as thermal stability, ionic conductivity, and volatility, leading to the designation of certain ILs as designer “green” solvents. The effect of counterions on the properties of ILs is of both fundamental scientific interest and technological importance. Herein, we report a systematic experimental and theoretical investigation of the size, charge, stability toward dissociation, and geometric/electronic structure of 1-ethyl-3-methyl imidazolium (EMIM)-based IL clusters containing two different atomic counterions (i.e., bromide [Br − ] and iodide [I − ]). This work extends our studies of EMIM + cations with atomic chloride (Cl − ) and molecular tetrafluoroborate (BF 4 − ) anions reported previously by Baxter et al. [Chem. Mater. 34, 2612 (2022)] and Zhang et al . [J. Phys. Chem. Lett. 11, 6844 (2020)], respectively. Distributions of anionic IL clusters were generated in the gas phase using electrospray ionization and characterized by high mass resolution mass spectrometry, energy-resolved collision-induced dissociation, and negative ion photoelectron spectroscopy experiments. The experimental results reveal anion-dependent trends in the size distribution, relative abundance, ionic charge state, stability toward dissociation, and electron binding energies of the IL clusters. Complementary global optimization theory provides molecular-level insights into the bonding and electronic structure of a selected subset of clusters, including their low energy structures and electrostatic potential maps, and how these fundamental characteristics are influenced by anion substitution. Collectively, our findings demonstrate how the fundamental properties of ILs, which determine their suitability for many applications, may be tuned by substituting counterions. These observations are critical in the sub-nanometer cluster size regime where phenomena do not scale predictably to the bulk phase, and each atom counts toward determining behavior.

cluster↗
DOE OSTI2020

Materials Data on B20H26O by Materials Project

(B3H4)2(BH)8B6H8OH2 crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of thirty-two boranediylradical molecules, eight hydrogen molecules, eight B3H4 clusters, and four B6H8O clusters. In each B3H4 cluster, there are three inequivalent B+1.20- sites. In the first B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.40 Å) B–H bond length. In the second B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. Both B–H bond lengths are 1.28 Å. In the third B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.40 Å) B–H bond length. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the third H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. In the fourth H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. In each B6H8O cluster, there are three inequivalent B+1.20- sites. In the first B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.30 Å) B–H bond length. In the second B+1.20- site, B+1.20- is bonded in a 3-coordinate geometry to two H1+ and one O2- atom. Both B–H bond lengths are 1.41 Å. The B–O bond length is 1.37 Å. In the third B+1.20- site, B+1.20- is bonded in a water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.30 Å) B–H bond length. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the third H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. In the fourth H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. O2- is bonded in a bent 150 degrees geometry to two equivalent B+1.20- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B10H13Br by Materials Project

(BH)4B3H5B3H4Br crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of sixteen boranediylradical molecules, four B3H4Br clusters, and four B3H5 clusters. In each B3H4Br cluster, there are three inequivalent B+1.20- sites. In the first B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.32 Å) B–H bond length. In the second B+1.20- site, B+1.20- is bonded in a distorted trigonal non-coplanar geometry to two H1+ and one Br1- atom. Both B–H bond lengths are 1.37 Å. The B–Br bond length is 1.94 Å. In the third B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.31 Å) B–H bond length. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. In the second H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the third H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. Br1- is bonded in a single-bond geometry to one B+1.20- atom. In each B3H5 cluster, there are three inequivalent B+1.20- sites. In the first B+1.20- site, B+1.20- is bonded in a distorted trigonal non-coplanar geometry to three H1+ atoms. There are a spread of B–H bond distances ranging from 1.19–1.35 Å. In the second B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.34 Å) B–H bond length. In the third B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.33 Å) B–H bond length. There are five inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the fourth H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. In the fifth H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B10H13Cl by Materials Project

(BH)4B3H5B3H4Cl crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of sixteen boranediylradical molecules, four B3H4Cl clusters, and four B3H5 clusters. In each B3H4Cl cluster, there are three inequivalent B+1.20- sites. In the first B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.31 Å) B–H bond length. In the second B+1.20- site, B+1.20- is bonded in a distorted trigonal non-coplanar geometry to two H1+ and one Cl1- atom. There is one shorter (1.37 Å) and one longer (1.38 Å) B–H bond length. The B–Cl bond length is 1.77 Å. In the third B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.31 Å) B–H bond length. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. In the second H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the third H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. Cl1- is bonded in a single-bond geometry to one B+1.20- atom. In each B3H5 cluster, there are three inequivalent B+1.20- sites. In the first B+1.20- site, B+1.20- is bonded in a distorted trigonal non-coplanar geometry to three H1+ atoms. There is one shorter (1.19 Å) and two longer (1.34 Å) B–H bond length. In the second B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.33 Å) B–H bond length. In the third B+1.20- site, B+1.20- is bonded in a distorted water-like geometry to two H1+ atoms. There is one shorter (1.19 Å) and one longer (1.33 Å) B–H bond length. There are five inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one B+1.20- atom. In the fourth H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms. In the fifth H1+ site, H1+ is bonded in an L-shaped geometry to two B+1.20- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B9H11N4 by Materials Project

B3H5(BH)3B3N4H3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of twelve boranediylradical molecules, four B3H5 clusters, and four B3N4H3 clusters. In each B3H5 cluster, there are three inequivalent B+0.33+ sites. In the first B+0.33+ site, B+0.33+ is bonded in a water-like geometry to two H+0.82+ atoms. There is one shorter (1.19 Å) and one longer (1.31 Å) B–H bond length. In the second B+0.33+ site, B+0.33+ is bonded in a trigonal non-coplanar geometry to three H+0.82+ atoms. There are a spread of B–H bond distances ranging from 1.19–1.39 Å. In the third B+0.33+ site, B+0.33+ is bonded in a water-like geometry to two H+0.82+ atoms. There is one shorter (1.19 Å) and one longer (1.30 Å) B–H bond length. There are five inequivalent H+0.82+ sites. In the first H+0.82+ site, H+0.82+ is bonded in a single-bond geometry to one B+0.33+ atom. In the second H+0.82+ site, H+0.82+ is bonded in a single-bond geometry to one B+0.33+ atom. In the third H+0.82+ site, H+0.82+ is bonded in an L-shaped geometry to two B+0.33+ atoms. In the fourth H+0.82+ site, H+0.82+ is bonded in an L-shaped geometry to two B+0.33+ atoms. In the fifth H+0.82+ site, H+0.82+ is bonded in a single-bond geometry to one B+0.33+ atom. In each B3N4H3 cluster, there are three inequivalent B+0.33+ sites. In the first B+0.33+ site, B+0.33+ is bonded in a bent 120 degrees geometry to one N3- and one H+0.82+ atom. The B–N bond length is 1.51 Å. The B–H bond length is 1.19 Å. In the second B+0.33+ site, B+0.33+ is bonded in a bent 120 degrees geometry to two N3- atoms. There is one shorter (1.46 Å) and one longer (1.49 Å) B–N bond length. In the third B+0.33+ site, B+0.33+ is bonded in a bent 120 degrees geometry to one N3- and one H+0.82+ atom. The B–N bond length is 1.65 Å. The B–H bond length is 1.19 Å. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded in a 4-coordinate geometry to three B+0.33+ and one H+0.82+ atom. The N–H bond length is 1.02 Å. In the second N3- site, N3- is bonded in a single-bond geometry to one N3- atom. The N–N bond length is 1.15 Å. In the third N3- site, N3- is bonded in a linear geometry to two N3- atoms. The N–N bond length is 1.22 Å. In the fourth N3- site, N3- is bonded in a distorted bent 120 degrees geometry to one B+0.33+ and one N3- atom. There are three inequivalent H+0.82+ sites. In the first H+0.82+ site, H+0.82+ is bonded in a single-bond geometry to one B+0.33+ atom. In the second H+0.82+ site, H+0.82+ is bonded in a single-bond geometry to one B+0.33+ atom. In the third H+0.82+ site, H+0.82+ is bonded in a single-bond geometry to one N3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

The Surface Chemistry of Methanol on Cu 3 Pd(111): Effects of Metal Alloying and Reaction with Hydrogen

Synchrotron-based ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) was used to study the adsorption and surface chemistry of methanol on a Cu 3 Pd(111) model surface. The composition and morphological properties of the pristine Cu 3 Pd(111) substrate were analyzed using a combination of low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), and low-energy ion scattering (LEIS). The results of ion scattering showed segregation of Pd toward the surface, with a Pd/Cu ratio close to 0.5, a larger value than the ratio of 0.33 expected for a Cu 3 Pd bimetallic structure. The surface of the alloy exhibited a good LEED pattern with three-fold long-range periodicities. In STM, clusters of palladium with hexagonal arrays and Pd- Pd distances of 2.7-2.8 Å were detected. Bonding to copper perturbed the electronic properties of the atoms in the Pd clusters, shifting their 4d states toward higher binding energy with respect to the Fermi level. Further, the valence band spectrum of Cu 3 Pd(111) exhibited a line shape that was very different from those displayed by Cu(111) or Pd(111). At low pressures, the adsorption of methanol on Cu 3 Pd(111) at 300 K mainly produced CH 3 O, CO and CH x species. AP-XPS showed that most Pd atoms in the surface of the Cu 3 Pd(111) alloy interacted with the decomposition products of methanol. No significant changes were observed in the core levels of copper upon the adsorption and dissociation of methanol, suggesting that the molecule mainly interacted with Pd sites of the alloy. Reaction with hydrogen led to fast removal of CH x , C and PdC x species from Cu 3 Pd(111) at moderate (< 450 K) temperatures and prevented a CH x → C transformation. If the stability of adsorbed CH 3 O is used as a descriptor for the hydrogenation of CO 2 to methanol, Cu 3 Pd should be a much better catalyst than monometallic palladium. This may be a consequence of electronic and ensemble effects in the alloy that moderate the reactivity of Pd sites.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on B13H19 by Materials Project

B5H8(BH)4B4H7 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of sixteen boranediylradical molecules, four B4H7 clusters, and four B5H8 clusters. In each B4H7 cluster, there are four inequivalent B+1.15- sites. In the first B+1.15- site, B+1.15- is bonded in a distorted water-like geometry to two H+0.79+ atoms. There is one shorter (1.20 Å) and one longer (1.32 Å) B–H bond length. In the second B+1.15- site, B+1.15- is bonded in a distorted water-like geometry to two H+0.79+ atoms. There is one shorter (1.19 Å) and one longer (1.32 Å) B–H bond length. In the third B+1.15- site, B+1.15- is bonded in a distorted trigonal non-coplanar geometry to three H+0.79+ atoms. There are a spread of B–H bond distances ranging from 1.19–1.36 Å. In the fourth B+1.15- site, B+1.15- is bonded in a distorted trigonal non-coplanar geometry to three H+0.79+ atoms. There is one shorter (1.19 Å) and two longer (1.35 Å) B–H bond length. There are seven inequivalent H+0.79+ sites. In the first H+0.79+ site, H+0.79+ is bonded in a single-bond geometry to one B+1.15- atom. In the second H+0.79+ site, H+0.79+ is bonded in a single-bond geometry to one B+1.15- atom. In the third H+0.79+ site, H+0.79+ is bonded in an L-shaped geometry to two B+1.15- atoms. In the fourth H+0.79+ site, H+0.79+ is bonded in a single-bond geometry to one B+1.15- atom. In the fifth H+0.79+ site, H+0.79+ is bonded in an L-shaped geometry to two B+1.15- atoms. In the sixth H+0.79+ site, H+0.79+ is bonded in a single-bond geometry to one B+1.15- atom. In the seventh H+0.79+ site, H+0.79+ is bonded in an L-shaped geometry to two B+1.15- atoms. In each B5H8 cluster, there are five inequivalent B+1.15- sites. In the first B+1.15- site, B+1.15- is bonded in a distorted trigonal non-coplanar geometry to three H+0.79+ atoms. There are a spread of B–H bond distances ranging from 1.19–1.36 Å. In the second B+1.15- site, B+1.15- is bonded in a distorted trigonal non-coplanar geometry to three H+0.79+ atoms. There are a spread of B–H bond distances ranging from 1.19–1.36 Å. In the third B+1.15- site, B+1.15- is bonded in a distorted water-like geometry to two H+0.79+ atoms. There is one shorter (1.20 Å) and one longer (1.32 Å) B–H bond length. In the fourth B+1.15- site, B+1.15- is bonded in a distorted trigonal non-coplanar geometry to three H+0.79+ atoms. There are a spread of B–H bond distances ranging from 1.19–1.33 Å. In the fifth B+1.15- site, B+1.15- is bonded in a distorted single-bond geometry to one H+0.79+ atom. The B–H bond length is 1.40 Å. There are eight inequivalent H+0.79+ sites. In the first H+0.79+ site, H+0.79+ is bonded in an L-shaped geometry to two B+1.15- atoms. In the second H+0.79+ site, H+0.79+ is bonded in an L-shaped geometry to two B+1.15- atoms. In the third H+0.79+ site, H+0.79+ is bonded in an L-shaped geometry to two B+1.15- atoms. In the fourth H+0.79+ site, H+0.79+ is bonded in a single-bond geometry to one B+1.15- atom. In the fifth H+0.79+ site, H+0.79+ is bonded in a single-bond geometry to one B+1.15- atom. In the sixth H+0.79+ site, H+0.79+ is bonded in an L-shaped geometry to two B+1.15- atoms. In the seventh H+0.79+ site, H+0.79+ is bonded in a single-bond geometry to one B+1.15- atom. In the eighth H+0.79+ site, H+0.79+ is bonded in a single-bond geometry to one B+1.15- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on C8I3N4 by Materials Project

(C2N)4(I)3 is Modderite structured and crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four C2N clusters and four I clusters. In each C2N cluster, there are six inequivalent C+1.88+ sites. In the first C+1.88+ site, C+1.88+ is bonded in a single-bond geometry to one C+1.88+ and one N3- atom. The C–C bond length is 1.30 Å. The C–N bond length is 1.25 Å. In the second C+1.88+ site, C+1.88+ is bonded in a water-like geometry to two N3- atoms. There is one shorter (1.36 Å) and one longer (1.59 Å) C–N bond length. In the third C+1.88+ site, C+1.88+ is bonded in a water-like geometry to two equivalent C+1.88+ atoms. In the fourth C+1.88+ site, C+1.88+ is bonded in a linear geometry to two N3- atoms. There is one shorter (1.19 Å) and one longer (1.30 Å) C–N bond length. In the fifth C+1.88+ site, C+1.88+ is bonded in a distorted single-bond geometry to one C+1.88+ and one N3- atom. The C–C bond length is 1.27 Å. The C–N bond length is 1.28 Å. In the sixth C+1.88+ site, C+1.88+ is bonded in a single-bond geometry to one C+1.88+ atom. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to two C+1.88+ atoms. In the second N3- site, N3- is bonded in a bent 120 degrees geometry to two C+1.88+ atoms. In the third N3- site, N3- is bonded in a trigonal non-coplanar geometry to three C+1.88+ atoms. In each I cluster, there are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a single-bond geometry to one I1- atom. The I–I bond length is 2.89 Å. In the second I1- site, I1- is bonded in a linear geometry to two equivalent I1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Facile and dynamic cleavage of every iron–sulfide bond in cuboidal iron–sulfur clusters

Nature employs weak-field metalloclusters to support a wide range of biological processes. The most ubiquitous metalloclusters are the cuboidal Fe–S clusters, which are comprised of Fe sites with locally high-spin electronic configurations. Such configurations enhance rates of ligand exchange and imbue the clusters with a degree of structural plasticity that is increasingly thought to be functionally relevant. Here, we examine this phenomenon using isotope tracing experiments. Specifically, we demonstrate that synthetic [Fe 4 S 4 ] and [MoFe 3 S 4 ] clusters exchange their Fe atoms with Fe 2+ ions dissolved in solution, a process that involves the reversible cleavage and reformation of every Fe–S bond in the cluster core. This exchange is facile—in most cases occurring at room temperature on the timescale of minutes—and documented over a range of cluster core oxidation states and terminal ligation patterns. In addition to suggesting a highly dynamic picture of cluster structure, these results provide a method for isotopically labeling pre-formed clusters with spin-active nuclei, such as 57 Fe. Such a protocol is demonstrated for the radical S -adenosyl- l -methionine enzyme, RlmN.

Science & Technology - Other Topics↗
NASA NTRS1977

Properties of small Ar sub N-1 K/+/ ionic clusters

A self-consistent formalism is developed that, based upon a many-body potential, dynamically determines the thermodynamic properties of ionic clusters without an a priori designation of the equilibrium structures. Aggregates consisting of a single closed shell K(+) ion and N-1 isoelectronic argon atoms were studied. The clusters form crystallites at low temperatures, and melting transitions and spontaneous dissociations are indicated. The results confirm experimental evidence that shows that ionic clusters become less stable with increasing N. The crystallite structures formed by four different clusters are isosceles triangle, skewed form, octahedron with ion in the middle, and icosahedron with the ion in the middle.

Etters, R. D.↗