Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Ag(NO)3”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Low Temperature Oxygen Activation on the NiAg(100) Single-Atom Alloy Surface

Silver-catalyzed ethylene epoxidation remains the only industrially viable route for ethylene oxide (EO) production. However, this process requires chlorine and other promoters to achieve a high EO selectivity while still generating substantial CO 2 emissions. A recent theory-guided approach identified Ni, in single-atom alloy (SAA) form, as a new promoter of this reaction. Specifically, the addition of Ni to Ag nanoparticles supported on α-Al 2 O 3 at a highly diluted ratio (1 Ni per 200 Ag atoms) increased catalyst selectivity to EO by ∼25%, the same increase afforded by the ubiquitous industrial promoter chlorine. To better understand the effect of Ni, we investigated the interaction of O 2 with NiAg(100) SAA surfaces by using scanning tunneling microscopy (STM) and density functional theory (DFT). While only molecular O 2 was present when pure Ag(100) was exposed to O 2 at 78 K, a distinct NiO 2 species, indicative of O 2 dissociation at Ni atom sites, was identified on the NiAg(100) SAA under the same conditions. High-resolution STM imaging backed by DFT simulations elucidated the formation of an O−Ni−O species with the oxygen atoms in 4-fold hollow sites. These findings provide direct experimental evidence that Ni atoms are very effective at O 2 activation, even at cryogenic temperatures. This suggests that, in addition to the known role of Ni in stabilizing the unselective nucleophilic oxygen on Ag, it could also accelerate O 2 dissociation, which can be rate limiting.

Catalysts↗
DOE OSTI2020

Materials Data on AgSbO3 by Materials Project

AgSbO3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.41–2.50 Å. In the second Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.36–2.53 Å. In the third Ag1+ site, Ag1+ is bonded in a single-bond geometry to one O2- atom. The Ag–O bond length is 2.28 Å. In the fourth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to six O2- atoms. There are a spread of Ag–O bond distances ranging from 2.45–2.97 Å. In the fifth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to four O2- atoms. There are a spread of Ag–O bond distances ranging from 2.35–2.62 Å. In the sixth Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to five O2- atoms. There are a spread of Ag–O bond distances ranging from 2.38–2.91 Å. In the seventh Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.37–2.48 Å. In the eighth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to five O2- atoms. There are a spread of Ag–O bond distances ranging from 2.39–2.78 Å. In the ninth Ag1+ site, Ag1+ is bonded in a distorted single-bond geometry to one O2- atom. The Ag–O bond length is 2.21 Å. In the tenth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.41–2.47 Å. In the eleventh Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.35–2.49 Å. In the twelfth Ag1+ site, Ag1+ is bonded in a 6-coordinate geometry to five O2- atoms. There are a spread of Ag–O bond distances ranging from 2.51–2.72 Å. There are twelve inequivalent Sb5+ sites. In the first Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Sb–O bond distances ranging from 1.98–2.06 Å. In the second Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Sb–O bond distances ranging from 1.98–2.06 Å. In the third Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 55–57°. There are a spread of Sb–O bond distances ranging from 1.98–2.06 Å. In the fourth Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Sb–O bond distances ranging from 1.98–2.05 Å. In the fifth Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Sb–O bond distances ranging from 1.97–2.07 Å. In the sixth Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Sb–O bond distances ranging from 1.99–2.06 Å. In the seventh Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Sb–O bond distances ranging from 1.96–2.08 Å. In the eighth Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Sb–O bond distances ranging from 1.97–2.05 Å. In the ninth Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 56–58°. There are a spread of Sb–O bond distances ranging from 2.00–2.03 Å. In the tenth Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Sb–O bond distances ranging from 1.99–2.05 Å. In the eleventh Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 55–58°. There are a spread of Sb–O bond distances ranging from 1.96–2.05 Å. In the twelfth Sb5+ site, Sb5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 55–57°. There are a spread of Sb–O bond distances ranging from 1.99–2.06 Å. There are thirty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ag1+ and two Sb5+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ag1+ and two Sb5+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Ag1+ and two Sb5+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ag1+ and two Sb5+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ag1+ and two Sb5+ atoms. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the eleventh O2- site, O2- is bonded in a distorted water-like geometry to two Ag1+ and two Sb5+ atoms. In the twelfth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ag1+ and two Sb5+ atoms. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ag1+ and two Sb5+ atoms. In the fifteenth O2- site, O2- is bonded to two Ag1+ and two Sb5+ atoms to form distorted corner-sharing OAg2Sb2 tetrahedra. In the sixteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ag1+ and two Sb5+ atoms. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ag1+ and two Sb5+ atoms. In the nineteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ag1+ and two Sb5+ atoms. In the twentieth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Sb5+ atoms. In the twenty-first O2- site, O2- is bonded in a 3-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the twenty-third O2- site, O2- is bonded in a water-like geometry to two Sb5+ atoms. In the twenty-fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ag1+ and two Sb5+ atoms. In the twenty-fifth O2- site, O2- is bonded in a distorted water-like geometry to one Ag1+ and two Sb5+ atoms. In the twenty-sixth O2- site, O2- is bonded in a distorted water-like geometry to one Ag1+ and two Sb5+ atoms. In the twenty-seventh O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ag1+ and two Sb5+ atoms. In the twenty-eighth O2- site, O2- is bonded in a 2-coordinate geometry to two Ag1+ and two Sb5+ atoms. In the twenty-ninth O2- site, O2- is bonded to two Ag1+ and two Sb5+ atoms to form distorted corner-sharing OAg2Sb2 tetrahedra. In the thirtieth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ag1+ and two Sb5+ atoms. In the thirty-first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ag1+ and two Sb5+ atoms. In the thirty-second O2- site, O2- is bonded in a 4-coordinate geometry to two Ag1+ and two Sb5+ atoms. In the thirty-third O2- site, O2- is bonded in a 2-coordinate geometry to two Ag1+ and two Sb5+ atoms. In the thirty-fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Ag1+ and two Sb5+ atoms. In the thirty-fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Ag1+ and two Sb5+ atoms. In the thirty-sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Sb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Silver(I) Supported Liquid Membranes for Selective Ethylene Recovery from Mixed-Gas Streams of Tandem CO 2 Electrolysis

Large-scale olefin separations from unreacted paraffins and other byproduct gases are primarily done by energy-intensive cryogenic distillation processes at refineries. Silver(I) supported liquid membranes (Ag SLMs) can be implemented at smaller production scales of ethylene (C 2 H 4 ), a critical industrial chemical, such as its electrocatalytic (EC) production from CO 2 . Challenges of EC C 2 H 4 production mainly stem from reducing gases like hydrogen (H 2 ), where the redox reactions pertinent to Ag(I) facilitators diminish olefin transport. Herein we report that aqueous Ag(I) solution in a composite Ag SLM can operate in mixed-gas conditions containing H 2 gas utilizing reduced titania compounds, such as titanium(III) oxide (Ti 2 O 3 ). Embedding Ti 2 O 3 in the polydimethylsiloxane layer of Ag SLM assisted in selectively separating C 2 H 4 from mixed-gas feed streams related to CO 2 electrolysis containing H 2 . The direct exposure of a mixed-gas stream containing C 2 H 4 , CO 2 , CO, N 2 , and CH 4 with as high as 50 vol % H 2 maintained excellent C 2 H 4 separations for 7 days of continuous operation. The Ag SLM provided effective separations of C 2 H 4 from CO (at detection limits), CH 4 (selectivity ratio (α) = 20–30), and H 2 (α = ∼20), but C 2 H 4 from CO 2 (α = 2–4) revealed a slightly lower separation. These data show that aqueous Ag(I) solution(s) used in the SLMs can separate C 2 H 4 for extended periods, even under highly reducing gas conditions. Also, we report C 2 H 4 recovery from the gas mixture produced in the EC CO 2 reduction process. In conclusion, the Ag SLM gave C 2 H 4 selective separation from a five-component complex mixed-gas stream, relevant to tandem CO 2 electrolysis.

37 - INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL C↗
DOE OSTI2020

Materials Data on AgClO3 by Materials Project

AgClO3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ag is bonded in a 4-coordinate geometry to five O atoms. There are a spread of Ag–O bond distances ranging from 2.48–2.78 Å. There are three inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two equivalent Ag and one Cl atom. The O–Cl bond length is 1.51 Å. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Ag and one Cl atom. The O–Cl bond length is 1.51 Å. In the third O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Ag and one Cl atom. The O–Cl bond length is 1.53 Å. Cl is bonded in a trigonal non-coplanar geometry to three O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AgClO4 by Materials Project

AgClO4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ag is bonded to six O atoms to form distorted AgO6 octahedra that share corners with six equivalent ClO4 tetrahedra and edges with two equivalent AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.55–2.71 Å. There are three inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two equivalent Ag and one Cl atom. The O–Cl bond length is 1.48 Å. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Ag and one Cl atom. The O–Cl bond length is 1.46 Å. In the third O site, O is bonded in a distorted bent 150 degrees geometry to one Ag and one Cl atom. The O–Cl bond length is 1.45 Å. Cl is bonded to four O atoms to form ClO4 tetrahedra that share corners with six equivalent AgO6 octahedra. The corner-sharing octahedra tilt angles range from 20–68°.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Control of iodine and tellurium for use in domestic molybdenum-99 production efforts

Three initial proof-of-concept experiments were performed to test the removal of I and Te from solutions containing Mo for potential abatement during chemical processing to purify 99 Mo. All three proof-of-concept experiments produced results indicating that further optimization could provide methods for I and/or Te abatement from multiple matrices. Decamp and Happel (2013) describe the use of CL resin from Eichrom Technologies loaded with Ag + combined with Amberlite XAD-4 in the chromatographic separation of irradiated fission products in 1 M HNO 3 to separate iodine species where iodide and iodate react with Ag + and I2 adheres to the Amberlite resin. The method worked well under processing conditions in a medical isotope facility although many separation methods use higher concentrations of HNO 3 which could adversely impact the Ag + loading. The experiment performed here used a roughly 2 mL column of CL resin loaded with Ag + and Amberlite XAD-4 to separate µg quantities of I, Te, and Mo in 3 M HNO 3 .

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2020

Materials Data on LiAg2F4 by Materials Project

LiAg2F4 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a tetrahedral geometry to four F1- atoms. There is two shorter (1.88 Å) and two longer (1.89 Å) Li–F bond length. In the second Li1+ site, Li1+ is bonded in a tetrahedral geometry to four F1- atoms. All Li–F bond lengths are 1.89 Å. There are four inequivalent Ag+1.50+ sites. In the first Ag+1.50+ site, Ag+1.50+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Ag–F bond distances ranging from 2.21–2.81 Å. In the second Ag+1.50+ site, Ag+1.50+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Ag–F bond distances ranging from 2.20–2.80 Å. In the third Ag+1.50+ site, Ag+1.50+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Ag–F bond distances ranging from 2.20–2.79 Å. In the fourth Ag+1.50+ site, Ag+1.50+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Ag–F bond distances ranging from 2.20–2.82 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 1-coordinate geometry to one Li1+ and three Ag+1.50+ atoms. In the second F1- site, F1- is bonded in a 1-coordinate geometry to one Li1+ and three Ag+1.50+ atoms. In the third F1- site, F1- is bonded in a 1-coordinate geometry to one Li1+ and three Ag+1.50+ atoms. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to one Li1+ and three Ag+1.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Modification of Catalytic Properties of Hollandite Manganese Oxide by Ag Intercalation for Oxidative Acetalization of Ethanol to Diethoxyethane

The effect of addition of Ag to the catalytic properties of hollandite manganese oxide (HMO) was investigated for the oxidative acetalization of ethanol to diethoxyethane. Based on analysis with HRTEM, XRD, and EXAFS, Ag introduced onto HMO by deposition/precipitation was found to be present in different forms in the final catalyst depending on the calcination temperature. It could exist as nanoparticles on the outside surface of HMO nanorods for samples calcined at 60 °C, and as Ag atoms intercalated into the tunnels of the HMO structure for samples calcined at 500 °C. NH 3 desorption results showed that intercalation of Ag resulted in stronger Lewis acidic sites on HMO, which DFT computational results suggested to be due to Ag-induced electron redistribution in the HMO framework. Here, the intercalation of Ag atoms also made the HMO more easily reducible by lowering the H 2 reduction temperature from 500 to 200 °C. Consequently, the sample with intercalated Ag was more active for ethanol oxidation to acetaldehyde, achieving nearly 100% conversion of ethanol and acetaldehyde by 360 °C, and acetalization of acetaldehyde with ethanol to produce diethoxyethane selectively, resulting in 93.5% diethoxyethane yield, which was 10% higher than with samples containing Ag nanoparticles on HMO. This study demonstrated a little-studied phenomenon in which a metal alters the catalytic properties of an oxide electronically but not structurally and without direct participation in the reaction.

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

Materials Data on BaSc3AgS6 by Materials Project

BaSc3AgS6 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Ba–S bond distances ranging from 3.17–3.61 Å. There are four inequivalent Sc3+ sites. In the first Sc3+ site, Sc3+ is bonded to six S2- atoms to form ScS6 octahedra that share a cornercorner with one ScS6 octahedra, corners with two equivalent AgS5 trigonal bipyramids, a cornercorner with one AgS4 trigonal pyramid, and edges with six ScS6 octahedra. The corner-sharing octahedral tilt angles are 9°. There are a spread of Sc–S bond distances ranging from 2.56–2.63 Å. In the second Sc3+ site, Sc3+ is bonded to six S2- atoms to form ScS6 octahedra that share a cornercorner with one ScS6 octahedra, edges with six ScS6 octahedra, an edgeedge with one AgS4 trigonal pyramid, and a faceface with one AgS5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 12°. There are a spread of Sc–S bond distances ranging from 2.57–2.65 Å. In the third Sc3+ site, Sc3+ is bonded to six S2- atoms to form ScS6 octahedra that share a cornercorner with one ScS6 octahedra, corners with two equivalent AgS5 trigonal bipyramids, a cornercorner with one AgS4 trigonal pyramid, edges with six ScS6 octahedra, and an edgeedge with one AgS4 trigonal pyramid. The corner-sharing octahedral tilt angles are 9°. There are a spread of Sc–S bond distances ranging from 2.57–2.62 Å. In the fourth Sc3+ site, Sc3+ is bonded to six S2- atoms to form ScS6 octahedra that share a cornercorner with one ScS6 octahedra, a cornercorner with one AgS4 trigonal pyramid, edges with six ScS6 octahedra, and an edgeedge with one AgS5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 12°. There are a spread of Sc–S bond distances ranging from 2.55–2.66 Å. There are two inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded to five S2- atoms to form distorted AgS5 trigonal bipyramids that share corners with eight ScS6 octahedra, an edgeedge with one ScS6 octahedra, and a faceface with one ScS6 octahedra. The corner-sharing octahedra tilt angles range from 3–52°. There are a spread of Ag–S bond distances ranging from 2.61–2.83 Å. In the second Ag1+ site, Ag1+ is bonded to four S2- atoms to form AgS4 trigonal pyramids that share corners with five ScS6 octahedra and edges with three ScS6 octahedra. The corner-sharing octahedra tilt angles range from 3–62°. There are a spread of Ag–S bond distances ranging from 2.45–2.86 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to one Ba2+ and four Sc3+ atoms to form distorted SBaSc4 trigonal bipyramids that share a cornercorner with one SBa2Sc3Ag octahedra, corners with six SBaSc4 trigonal bipyramids, an edgeedge with one SBa2Sc3Ag octahedra, and edges with five SBaSc4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 52°. In the second S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, three Sc3+, and one Ag1+ atom. In the third S2- site, S2- is bonded to two equivalent Ba2+, three Sc3+, and one Ag1+ atom to form a mixture of distorted corner and edge-sharing SBa2Sc3Ag octahedra. In the fourth S2- site, S2- is bonded to two equivalent Ba2+, two Sc3+, and one Ag1+ atom to form SBa2Sc2Ag trigonal bipyramids that share a cornercorner with one SBa2Sc3Ag octahedra, corners with seven SBaSc4 trigonal bipyramids, an edgeedge with one SBa2Sc3Ag octahedra, and edges with five SBaSc4 trigonal bipyramids. The corner-sharing octahedral tilt angles are 74°. In the fifth S2- site, S2- is bonded to one Ba2+, three Sc3+, and one Ag1+ atom to form SBaSc3Ag trigonal bipyramids that share corners with two equivalent SBa2Sc3Ag octahedra, corners with six SBaSc4 trigonal bipyramids, an edgeedge with one SBa2Sc3Ag octahedra, and edges with four SBaSc4 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 3–32°. In the sixth S2- site, S2- is bonded in a rectangular see-saw-like geometry to four Sc3+ atoms. In the seventh S2- site, S2- is bonded to one Ba2+, three Sc3+, and one Ag1+ atom to form distorted SBaSc3Ag trigonal bipyramids that share corners with six SBaSc4 trigonal bipyramids, an edgeedge with one SBa2Sc3Ag octahedra, and edges with five SBaSc4 trigonal bipyramids. In the eighth S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Ba2+, two equivalent Sc3+, and one Ag1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NbAg7S6 by Materials Project

Ag7NbS6 crystallizes in the monoclinic Pc space group. The structure is three-dimensional. Nb5+ is bonded to four S2- atoms to form NbS4 tetrahedra that share an edgeedge with one AgS4 trigonal pyramid. There are a spread of Nb–S bond distances ranging from 2.31–2.37 Å. There are seven inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded to four S2- atoms to form distorted AgS4 trigonal pyramids that share an edgeedge with one NbS4 tetrahedra. There are a spread of Ag–S bond distances ranging from 2.52–2.79 Å. In the second Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.46–2.77 Å. In the third Ag1+ site, Ag1+ is bonded in a distorted linear geometry to two S2- atoms. There are one shorter (2.41 Å) and one longer (2.50 Å) Ag–S bond lengths. In the fourth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.54–2.67 Å. In the fifth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.54–2.66 Å. In the sixth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.48–2.79 Å. In the seventh Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four S2- atoms. There are a spread of Ag–S bond distances ranging from 2.62–2.85 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 6-coordinate geometry to six Ag1+ atoms. In the second S2- site, S2- is bonded in a 4-coordinate geometry to four Ag1+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to one Nb5+ and four Ag1+ atoms. In the fourth S2- site, S2- is bonded in a 1-coordinate geometry to one Nb5+ and three Ag1+ atoms. In the fifth S2- site, S2- is bonded in a 4-coordinate geometry to one Nb5+ and three Ag1+ atoms. In the sixth S2- site, S2- is bonded in a 3-coordinate geometry to one Nb5+ and two Ag1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Hidden Local Symmetry Breaking in Silver Diamondoid Compounds is Root Cause of Ultralow Thermal Conductivity

Typically, conventional structure transitions occur from a low symmetry state to a higher symmetry state upon warming. In this work, an unexpected local symmetry breaking in the tetragonal diamondoid compound AgGaTe 2 is reported, which, upon warming, evolves continuously from an undistorted ground state to a locally distorted state while retaining average crystallographic symmetry. This is a rare phenomenon previously referred to as emphanisis. This distorted state, caused by the weak sd 3 orbital hybridization of tetrahedral Ag atoms, causes their displacement off the tetrahedron center and promotes a global distortion of the crystal structure resulting in strong acoustic–optical phonon scattering and an ultralow lattice thermal conductivity of 0.26 W m –1 K –1 at 850 K in AgGaTe 2 . Here, the findings explain the underlying reason for the unexpectedly low thermal conductivities of silver-based compounds compared to copper-based analogs and provide a guideline to suppressing heat transport in diamondoid and other materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Trends in Formic Acid Electro-Oxidation on Transition Metals Alloyed with Platinum and Palladium

Direct formic acid fuel cells (DFAFCs) have emerged as a promising power source to meet increased demands for alternative energy sources in the transportation and portable energy storage sectors. Furthermore, these fuel cells utilize formic acid (FA), a nontoxic and carbon-neutral fuel when produced from biomass or via CO 2 reduction. Despite the promise of DFAFCs, the best monometallic catalysts, platinum and palladium, are poisoned by CO through the indirect oxidation pathway and require large overpotentials. By alloying Pt and Pd with other metals, we aim to improve both the activity and selectivity of these catalysts. Here, we present a systematic density functional theory (GGA-PW91) study of FA electro-oxidation (FAO) on the (111) facet of bimetallic Pt (Pt 3 M) or Pd (Pd 3 M) catalysts (M = Au, Ag, Cu, Pt, Pd, Ir, Rh, Ru, or Re) to evaluate the catalytic performance of these surfaces. For each surface, we calculate free energy diagrams and onset potentials of three key reaction mechanisms: direct oxidation of FA via carboxyl (COOH), direct oxidation of FA via formate (HCOO), and the indirect oxidation of FA that first forms CO en route to full oxidation to CO 2 . We then display the trends in the form of phase diagrams that compare the activity of the calculated surfaces against regions of high activity using the free energies of adsorbed CO and OH as descriptors, enabling high-throughput screening and design of improved catalysts, particularly those alloying Pt or Pd with Ir, Ru, or Re.

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

Materials Data on TaAg7S6 by Materials Project

Ag7TaS6 crystallizes in the monoclinic Pc space group. The structure is three-dimensional. Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share corners with two equivalent AgS4 tetrahedra. All Ta–S bond lengths are 2.32 Å. There are seven inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four S2- atoms. There are a spread of Ag–S bond distances ranging from 2.55–2.92 Å. In the second Ag1+ site, Ag1+ is bonded to four S2- atoms to form distorted AgS4 tetrahedra that share corners with two equivalent TaS4 tetrahedra. There are a spread of Ag–S bond distances ranging from 2.62–2.76 Å. In the third Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.52–2.57 Å. In the fourth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.52–2.69 Å. In the fifth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are two shorter (2.55 Å) and one longer (2.65 Å) Ag–S bond lengths. In the sixth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.52–2.66 Å. In the seventh Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to four S2- atoms. There are a spread of Ag–S bond distances ranging from 2.53–3.21 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 6-coordinate geometry to six Ag1+ atoms. In the second S2- site, S2- is bonded in a 4-coordinate geometry to one Ta5+ and three Ag1+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to five Ag1+ atoms. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to one Ta5+ and four Ag1+ atoms. In the fifth S2- site, S2- is bonded in a 4-coordinate geometry to one Ta5+ and three Ag1+ atoms. In the sixth S2- site, S2- is bonded in a 1-coordinate geometry to one Ta5+ and three Ag1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn3(AgO2)4 by Materials Project

Mn3(AgO2)4 is Orthorhombic Perovskite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Mn4+ sites. In the first Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one AgO4 trigonal pyramid and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–2.02 Å. In the second Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one AgO4 trigonal pyramid and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.89–2.01 Å. In the third Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one AgO4 trigonal pyramid and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.89–2.01 Å. In the fourth Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one AgO4 trigonal pyramid and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.90–2.01 Å. In the fifth Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one AgO4 trigonal pyramid and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.90–2.03 Å. In the sixth Mn4+ site, Mn4+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.89–2.06 Å. In the seventh Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one AgO4 trigonal pyramid and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.91–2.03 Å. In the eighth Mn4+ site, Mn4+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.90–2.04 Å. In the ninth Mn4+ site, Mn4+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.90–2.00 Å. In the tenth Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one AgO4 trigonal pyramid and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.89–2.02 Å. In the eleventh Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one AgO4 trigonal pyramid and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.91–2.10 Å. In the twelfth Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one AgO4 trigonal pyramid and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–2.00 Å. There are sixteen inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.17 Å) and one longer (2.30 Å) Ag–O bond lengths. In the second Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to two O2- atoms. Both Ag–O bond lengths are 2.25 Å. In the third Ag1+ site, Ag1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ag–O bond distances ranging from 2.45–2.87 Å. In the fourth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.28–2.51 Å. In the fifth Ag1+ site, Ag1+ is bonded in a distorted linear geometry to two O2- atoms. There are one shorter (2.09 Å) and one longer (2.15 Å) Ag–O bond lengths. In the sixth Ag1+ site, Ag1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ag–O bond distances ranging from 2.51–2.71 Å. In the seventh Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Ag–O bond distances ranging from 2.16–2.57 Å. In the eighth Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.11–2.88 Å. In the ninth Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Ag–O bond distances ranging from 2.16–2.55 Å. In the tenth Ag1+ site, Ag1+ is bonded to four O2- atoms to form distorted AgO4 trigonal pyramids that share corners with nine MnO6 octahedra. The corner-sharing octahedra tilt angles range from 44–61°. There are a spread of Ag–O bond distances ranging from 2.31–2.62 Å. In the eleventh Ag1+ site, Ag1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.14–2.42 Å. In the twelfth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Ag–O bond distances ranging from 2.19–2.32 Å. In the thirteenth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to four O2- atoms. There are a spread of Ag–O bond distances ranging from 2.22–2.65 Å. In the fourteenth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to four O2- atoms. There are a spread of Ag–O bond distances ranging from 2.13–2.70 Å. In the fifteenth Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.19 Å) and one longer (2.25 Å) Ag–O bond lengths. In the sixteenth Ag1+ site, Ag1+ is bonded in a 6-coordinate geometry to four O2- atoms. There are a spread of Ag–O bond distances ranging from 2.35–2.58 Å. There are thirty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Mn4+ and one Ag1+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Mn4+ and one Ag1+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Mn4+ and one Ag1+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Mn4+ and one Ag1+ atom. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mn4+ and one Ag1+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Mn4+ and two Ag1+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two Mn4+ and one Ag1+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Mn4+ and one Ag1+ atom. In the ninth O2- site, O2- is bonded to two Mn4+ and two Ag1+ atoms to form distorted corner-sharing OMn2Ag2 tetrahedra. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two Mn4+ and two Ag1+ atoms. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to two Mn4+ and two Ag1+ atoms. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to three Mn4+ and one Ag1+ atom. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Mn4+ and one Ag1+ atom. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Mn4+ and two Ag1+ atoms. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Mn4+ and two Ag1+ atoms. In the sixteenth O2- site, O2- is bonded to two Mn4+ and two Ag1+ atoms to form distorted corner-sharing OMn2Ag2 tetrahedra. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to two Mn4+ and three Ag1+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted tetrahedral geometry to two Mn4+ and two Ag1+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted water-like geometry to two Mn4+ and two Ag1+ atoms. In the twentieth O2- site, O2- is bonded in a 5-coordinate geometry to three Mn4+ and two Ag1+ atoms. In the twenty-first O2- site, O2- is bonded in a 4-coordinate geometry to three Mn4+ and one Ag1+ atom. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to two Mn4+ and two Ag1+ atoms. In the twenty-third O2- site, O2- is bonded in a 2-coordinate geometry to two Mn4+ and three Ag1+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 2-coordinate geometry to two Mn4+ and three Ag1+ atoms. In the twenty-fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Mn4+ and three Ag1+ atoms. In the twenty-sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Mn4+ and two Ag1+ atoms. In the twenty-seventh O2- site, O2- is bonded in a 3-coordinate geometry to two Mn4+ and two Ag1+ atoms. In the twenty-eighth O2- site, O2- is bonded in a 5-coordinate geometry to three Mn4+ and one Ag1+ atom. In the twenty-ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mn4+ and one Ag1+ atom. In the thirtieth O2- site, O2- is bonded in a distorted water-like geometry to two Mn4+ and two Ag1+ atoms. In the thirty-first O2- site, O2- is bonded in a distorted tetrahedral geometry to two Mn4+ and two Ag1+ atoms. In the thirty-second O2- site, O2- is bonded in a 3-coordinate geometry to two Mn4+ and two Ag1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ti(Ag4S3)2 by Materials Project

Ag8TiS6 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. Ti4+ is bonded to four S2- atoms to form TiS4 tetrahedra that share corners with two equivalent AgS4 tetrahedra and corners with two equivalent AgS4 trigonal pyramids. There are a spread of Ti–S bond distances ranging from 2.29–2.31 Å. There are eight inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.51–2.88 Å. In the second Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to four S2- atoms. There are a spread of Ag–S bond distances ranging from 2.48–3.46 Å. In the third Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.54–2.75 Å. In the fourth Ag1+ site, Ag1+ is bonded to four S2- atoms to form distorted AgS4 trigonal pyramids that share corners with two equivalent TiS4 tetrahedra and corners with three equivalent AgS4 tetrahedra. There are a spread of Ag–S bond distances ranging from 2.59–2.80 Å. In the fifth Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to four S2- atoms. There are a spread of Ag–S bond distances ranging from 2.55–3.20 Å. In the sixth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to four S2- atoms. There are a spread of Ag–S bond distances ranging from 2.56–3.29 Å. In the seventh Ag1+ site, Ag1+ is bonded to four S2- atoms to form distorted AgS4 tetrahedra that share corners with two equivalent TiS4 tetrahedra and corners with three equivalent AgS4 trigonal pyramids. There are a spread of Ag–S bond distances ranging from 2.62–2.72 Å. In the eighth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.55–2.75 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to eight Ag1+ atoms. In the second S2- site, S2- is bonded in a distorted trigonal bipyramidal geometry to one Ti4+ and four Ag1+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to one Ti4+ and four Ag1+ atoms. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to six Ag1+ atoms. In the fifth S2- site, S2- is bonded in a 1-coordinate geometry to one Ti4+ and four Ag1+ atoms. In the sixth S2- site, S2- is bonded in a 4-coordinate geometry to one Ti4+ and three Ag1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

All-atmospheric fabrication of Ag–Cu core–shell nanowire transparent electrodes with Haacke figure of merit >600 × 10–3 Ω−1

Abstract Transparent conducting electrodes (TCEs) are essential components in devices such as touch screens, smart windows, and photovoltaics. Metal nanowire networks are promising next-generation TCEs, but best-performing examples rely on expensive metal catalysts (palladium or platinum), vacuum processing, or transfer processes that cannot be scaled. This work demonstrates a metal nanowire TCE fabrication process that focuses on high performance and simple fabrication. Here we combined direct and plating metallization processes on electrospun nanowires. We first directly metallize silver nanowires using reactive silver ink. The silver catalyzes subsequent copper plating to produce Ag–Cu core–shell nanowires and eliminates nanowire junction resistances. The process allows for tunable transmission and sheet resistance properties by adjusting electrospinning and plating time. We demonstrate state-of-the-art, low-haze TCEs using an all-atmospheric process with sheet resistances of 0.33 Ω sq −1 and visible light transmittances of 86% (including the substrate), leading to a Haacke figure of merit of 652 × 10 –3 Ω −1 . The core–shell nanowire electrode also demonstrates high chemical and bending durability.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al(Ag3S2)3 by Materials Project

Ag9AlS6 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are nine inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.51–2.71 Å. In the second Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.52–2.78 Å. In the third Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.47–3.11 Å. In the fourth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are one shorter (2.51 Å) and two longer (2.68 Å) Ag–S bond lengths. In the fifth Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.46–2.92 Å. In the sixth Ag1+ site, Ag1+ is bonded in a distorted bent 150 degrees geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.46–3.25 Å. In the seventh Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.48–2.95 Å. In the eighth Ag1+ site, Ag1+ is bonded in a distorted linear geometry to two S2- atoms. There are one shorter (2.41 Å) and one longer (2.47 Å) Ag–S bond lengths. In the ninth Ag1+ site, Ag1+ is bonded in a 3-coordinate geometry to three S2- atoms. There are a spread of Ag–S bond distances ranging from 2.54–2.61 Å. Al3+ is bonded in a tetrahedral geometry to four S2- atoms. There are a spread of Al–S bond distances ranging from 2.24–2.30 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to four Ag1+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to four Ag1+ and one Al3+ atom. In the third S2- site, S2- is bonded in a distorted see-saw-like geometry to three Ag1+ and one Al3+ atom. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to four Ag1+ and one Al3+ atom. In the fifth S2- site, S2- is bonded in a 7-coordinate geometry to six Ag1+ and one Al3+ atom. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to five Ag1+ atoms.

36 MATERIALS SCIENCE↗