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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Superconductivity with T c ≈ 7 K under pressure for Cu- and Au-doped BaFe 2 As 2

It is noteworthy that chemical substitution of BaFe 2 As 2 (122) with the noble elements Cu and Au gives superconductivity with a maximum T c ≈ 3 K, while Ag substitution (Ag-122) stays antiferromagnetic. For Ba(Fe 1–x TM x ) 2 As 2 , TM = Cu, Au, or Ag, and by doping an amount of x = 0.04, a-lattice parameter slightly increases (0.4%) for all TM dopants, while c-lattice decreases (–0.2%) for TM = Cu, barely moves (0.05%) for Au, and increases (0.2%) for Ag. Despite the naive expectation that the noble elements of group 11 should affect the quantum properties of 122 similarly, they produce significant differences extending to the character of the ground state. For the Ag-122 crystal, evidence of only a filamentary superconductivity is noted with pressure. However, for Au and Cu doping (x ≈ 0.03) we find a substantial improvement in the superconductivity, with T c increasing to 7 K and 7.5 K, respectively, under 20 kbar of pressure. As with the ambient pressure results, the identity of the dopant therefore has a substantial impact on the ground state properties. Further, density functional theory calculations corroborate these results and find evidence of strong electronic scattering for Au and Ag dopants, while Cu is comparatively less disruptive to the 122 electronic structure.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Materials Data on K3Ag2(PO4)5 by Materials Project

K3Ag2(PO4)5 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.78–3.06 Å. In the second K site, K is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of K–O bond distances ranging from 2.76–3.35 Å. In the third K site, K is bonded in a 4-coordinate geometry to four O atoms. There are a spread of K–O bond distances ranging from 2.58–3.22 Å. There are two inequivalent Ag sites. In the first Ag site, Ag is bonded in a 3-coordinate geometry to three O atoms. There are a spread of Ag–O bond distances ranging from 2.19–2.61 Å. In the second Ag site, Ag is bonded to six O atoms to form distorted AgO6 octahedra that share corners with five PO4 tetrahedra. There are a spread of Ag–O bond distances ranging from 2.01–2.55 Å. There are five inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share a cornercorner with one AgO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of P–O bond distances ranging from 1.50–1.62 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent AgO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of P–O bond distances ranging from 1.50–1.63 Å. In the third P site, P is bonded to four O atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.49–1.66 Å. In the fourth P site, P is bonded to four O atoms to form PO4 tetrahedra that share a cornercorner with one AgO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of P–O bond distances ranging from 1.49–1.64 Å. In the fifth P site, P is bonded to four O atoms to form PO4 tetrahedra that share a cornercorner with one AgO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of P–O bond distances ranging from 1.49–1.63 Å. There are twenty inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to one K, two equivalent Ag, and one P atom. In the second O site, O is bonded in a bent 150 degrees geometry to two P atoms. In the third O site, O is bonded in a distorted bent 120 degrees geometry to one K and two P atoms. In the fourth O site, O is bonded in a distorted single-bond geometry to two equivalent K, one Ag, and one P atom. In the fifth O site, O is bonded in a 1-coordinate geometry to one K, one Ag, and one P atom. In the sixth O site, O is bonded in a distorted single-bond geometry to two equivalent K, one Ag, and one P atom. In the seventh O site, O is bonded in a distorted bent 120 degrees geometry to one K and two P atoms. In the eighth O site, O is bonded in a distorted single-bond geometry to two K and one P atom. In the ninth O site, O is bonded in a distorted bent 120 degrees geometry to one K and one P atom. In the tenth O site, O is bonded in a bent 120 degrees geometry to one K and two P atoms. In the eleventh O site, O is bonded in a 1-coordinate geometry to one K, two Ag, and one P atom. In the twelfth O site, O is bonded in a distorted single-bond geometry to two K and one P atom. In the thirteenth O site, O is bonded in a 3-coordinate geometry to one K, one Ag, and one P atom. In the fourteenth O site, O is bonded in a 2-coordinate geometry to one K and one P atom. In the fifteenth O site, O is bonded in a bent 120 degrees geometry to two P atoms. In the sixteenth O site, O is bonded in a single-bond geometry to one Ag atom. In the seventeenth O site, O is bonded in a distorted bent 120 degrees geometry to one K and two O atoms. There is one shorter (1.30 Å) and one longer (1.31 Å) O–O bond length. In the eighteenth O site, O is bonded in an L-shaped geometry to one K and one O atom. In the nineteenth O site, O is bonded in a single-bond geometry to one K atom. In the twentieth O site, O is bonded in a bent 120 degrees geometry to one K and one O atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Binding the Power of Cycloaddition and Cross-Coupling in a Single Mechanism: An Unexpected Bending Journey to Radical Chemistry of Butadiynyl with Conjugated Dienes

What if an experiment could combine the power of cycloaddition and cross-coupling with the in situ formation of an aromatic molecule in a single collision? Crossed molecular beam experiments augmented with electronic structure and statistical calculations provided compelling evidence on a novel radical route involving 1,3-butadiynyl (HCCCC; X 2 Σ + ) radicals synthesizing (substituted) arylacetylenes in the gas phase upon reactions with 1,3-butadiene (CH 2 CHCHCH 2 ; X 1 Ag) and 2-methyl-1,3-butadiene (isoprene; CH 2 C(CH 3 )CHCH 2 ; X 1 A'). Furthermore, this elegant mechanism de facto merges two previously disconnected concepts of cross-coupling and cycloaddition–aromatization in a single collision event via the formation of two new C(sp 2 )–C(sp 2 ) bonds and bending the 180° moiety of the linear 1,3-butadiynyl radical out of the ordinary by 60° to 120°. In addition to its importance to fundamental organic chemistry, this unconventional mechanism links two previously separated routes of gas-phase molecular mass growth processes of polyacetylenes and polycyclic aromatic hydrocarbons (PAHs), respectively, in low-temperature environments such as in cold molecular clouds like the Taurus Molecular Cloud (TMC-1) and in hydrocarbon-rich atmospheres of planets and their moons such as Titan, what revises the established understanding of low-temperature molecular mass growth processes in the Universe.

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

Materials Data on Ag9(SI)4 by Materials Project

Ag9(SI)4 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are nine inequivalent Ag+1.33+ sites. In the first Ag+1.33+ site, Ag+1.33+ is bonded in a 6-coordinate geometry to three equivalent S2- and three equivalent I1- atoms. All Ag–S bond lengths are 2.64 Å. There are one shorter (3.06 Å) and two longer (3.39 Å) Ag–I bond lengths. In the second Ag+1.33+ site, Ag+1.33+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing AgI6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Ag–I bond distances ranging from 2.95–3.15 Å. In the third Ag+1.33+ site, Ag+1.33+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing AgI6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are two shorter (2.97 Å) and four longer (3.06 Å) Ag–I bond lengths. In the fourth Ag+1.33+ site, Ag+1.33+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing AgI6 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. There are a spread of Ag–I bond distances ranging from 2.95–3.13 Å. In the fifth Ag+1.33+ site, Ag+1.33+ is bonded to three equivalent S2- and three equivalent I1- atoms to form a mixture of distorted corner and edge-sharing AgS3I3 octahedra. The corner-sharing octahedra tilt angles range from 6–9°. There are two shorter (2.64 Å) and one longer (2.65 Å) Ag–S bond lengths. There are one shorter (3.06 Å) and two longer (3.34 Å) Ag–I bond lengths. In the sixth Ag+1.33+ site, Ag+1.33+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Ag–S bond distances ranging from 2.51–3.05 Å. In the seventh Ag+1.33+ site, Ag+1.33+ is bonded in a 3-coordinate geometry to three S2- atoms. There are two shorter (2.48 Å) and one longer (2.75 Å) Ag–S bond lengths. In the eighth Ag+1.33+ site, Ag+1.33+ is bonded in a distorted bent 120 degrees geometry to three equivalent S2- atoms. There are two shorter (2.45 Å) and one longer (3.44 Å) Ag–S bond lengths. In the ninth Ag+1.33+ site, Ag+1.33+ is bonded to six S2- atoms to form distorted edge-sharing AgS6 octahedra. There are a spread of Ag–S bond distances ranging from 2.53–3.03 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to six Ag+1.33+ atoms to form distorted SAg6 octahedra that share corners with three equivalent IAg6 octahedra, edges with three equivalent IAg6 octahedra, and edges with six equivalent SAg6 octahedra. The corner-sharing octahedra tilt angles range from 17–21°. In the second S2- site, S2- is bonded to six Ag+1.33+ atoms to form distorted SAg6 octahedra that share corners with three equivalent IAg6 octahedra, edges with three equivalent IAg6 octahedra, and edges with six equivalent SAg6 octahedra. The corner-sharing octahedra tilt angles range from 18–22°. In the third S2- site, S2- is bonded in a 3-coordinate geometry to five Ag+1.33+ atoms. In the fourth S2- site, S2- is bonded in a 3-coordinate geometry to seven Ag+1.33+ atoms. There are four inequivalent I1- sites. In the first I1- site, I1- is bonded to six Ag+1.33+ atoms to form IAg6 octahedra that share corners with three equivalent SAg6 octahedra, corners with three equivalent IAg6 octahedra, edges with three equivalent SAg6 octahedra, and edges with nine IAg6 octahedra. The corner-sharing octahedra tilt angles range from 3–22°. In the second I1- site, I1- is bonded to six Ag+1.33+ atoms to form a mixture of corner and edge-sharing IAg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the third I1- site, I1- is bonded to six Ag+1.33+ atoms to form a mixture of corner and edge-sharing IAg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the fourth I1- site, I1- is bonded to six Ag+1.33+ atoms to form IAg6 octahedra that share corners with three equivalent SAg6 octahedra, corners with three equivalent IAg6 octahedra, edges with three equivalent SAg6 octahedra, and edges with nine IAg6 octahedra. The corner-sharing octahedra tilt angles range from 3–21°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag3Te(AsO7)2 by Materials Project

Ag3Te(AsO7)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Ag sites. In the first Ag site, Ag is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Ag–O bond distances ranging from 2.03–2.68 Å. In the second Ag site, Ag is bonded in a see-saw-like geometry to four O atoms. There are a spread of Ag–O bond distances ranging from 2.10–2.24 Å. In the third Ag site, Ag is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Ag–O bond distances ranging from 2.03–2.69 Å. In the fourth Ag site, Ag is bonded in a see-saw-like geometry to four O atoms. There are two shorter (2.10 Å) and two longer (2.23 Å) Ag–O bond lengths. In the fifth Ag site, Ag is bonded in a distorted rectangular see-saw-like geometry to four O atoms. There are a spread of Ag–O bond distances ranging from 2.03–2.18 Å. In the sixth Ag site, Ag is bonded in a distorted rectangular see-saw-like geometry to four O atoms. There are a spread of Ag–O bond distances ranging from 2.03–2.17 Å. There are four inequivalent As sites. In the first As site, As is bonded in a tetrahedral geometry to four O atoms. There are a spread of As–O bond distances ranging from 1.70–1.80 Å. In the second As site, As is bonded in a tetrahedral geometry to four O atoms. There are a spread of As–O bond distances ranging from 1.70–1.79 Å. In the third As site, As is bonded in a tetrahedral geometry to four O atoms. There are a spread of As–O bond distances ranging from 1.70–1.80 Å. In the fourth As site, As is bonded in a tetrahedral geometry to four O atoms. There are a spread of As–O bond distances ranging from 1.70–1.80 Å. There are two inequivalent Te sites. In the first Te site, Te is bonded in a distorted octahedral geometry to six O atoms. There are a spread of Te–O bond distances ranging from 1.93–1.99 Å. In the second Te site, Te is bonded in an octahedral geometry to six O atoms. There are a spread of Te–O bond distances ranging from 1.93–1.99 Å. There are twenty-eight inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two Ag and one As atom. In the second O site, O is bonded in a 3-coordinate geometry to two Ag and one As atom. In the third O site, O is bonded in a 3-coordinate geometry to two Ag and one As atom. In the fourth O site, O is bonded in a 3-coordinate geometry to two Ag and one As atom. In the fifth O site, O is bonded in a single-bond geometry to one Te atom. In the sixth O site, O is bonded in a distorted bent 120 degrees geometry to one Ag and one Te atom. In the seventh O site, O is bonded in a single-bond geometry to one Te atom. In the eighth O site, O is bonded in a single-bond geometry to one Te atom. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to one Ag and one Te atom. In the tenth O site, O is bonded in a distorted bent 120 degrees geometry to one Ag and one Te atom. In the eleventh O site, O is bonded in a distorted bent 150 degrees geometry to one Ag and one Te atom. In the twelfth O site, O is bonded in a single-bond geometry to one Te atom. In the thirteenth O site, O is bonded in a distorted bent 150 degrees geometry to one Ag and one Te atom. In the fourteenth O site, O is bonded in a distorted bent 150 degrees geometry to one Ag and one Te atom. In the fifteenth O site, O is bonded in a single-bond geometry to one Te atom. In the sixteenth O site, O is bonded in a single-bond geometry to one Te atom. In the seventeenth O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the eighteenth O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the nineteenth O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the twentieth O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the twenty-first O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the twenty-second O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the twenty-third O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the twenty-fourth O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the twenty-fifth O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the twenty-sixth O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the twenty-seventh O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom. In the twenty-eighth O site, O is bonded in a bent 120 degrees geometry to one Ag and one As atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag2F by Materials Project

Ag2F is trigonal omega structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ag2F sheet oriented in the (0, 0, 1) direction. Ag is bonded in a 3-coordinate geometry to three equivalent F atoms. All Ag–F bond lengths are 2.51 Å. F is bonded to six equivalent Ag atoms to form distorted edge-sharing FAg6 octahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AgClO3 by Materials Project

AgClO3 crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three AgClO3 sheets oriented in the (0, 0, 1) direction. Ag is bonded in a 3-coordinate geometry to three equivalent O atoms. All Ag–O bond lengths are 2.59 Å. O is bonded in a distorted water-like geometry to one Ag and one Cl atom. The O–Cl bond length is 1.51 Å. Cl is bonded in a trigonal non-coplanar geometry to three equivalent O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

The AUREX cell: a versatile operando electrochemical cell for studying catalytic materials using X-ray diffraction, total scattering and X-ray absorption spectroscopy under working conditions

Understanding the structure–property relationship in electrocatalysts under working conditions is crucial for the rational design of novel and improved catalytic materials. This paper presents the Aarhus University reactor for electrochemical studies using X-rays (AUREX) operando electrocatalytic flow cell, designed as an easy-to-use versatile setup with a minimal background contribution and a uniform flow field to limit concentration polarization and handle gas formation. The cell has been employed to measure operando total scattering, diffraction and absorption spectroscopy as well as simultaneous combinations thereof on a commercial silver electrocatalyst for proof of concept. This combination of operando techniques allows for monitoring of the short-, medium- and long-range structure under working conditions, including an applied potential, liquid electrolyte and local reaction environment. The structural transformations of the Ag electrocatalyst are monitored with non-negative matrix factorization, linear combination analysis, the Pearson correlation coefficient matrix, and refinements in both real and reciprocal space. Upon application of an oxidative potential in an Ar-saturated aqueous 0.1 M KHCO 3 /K 2 CO 3 electrolyte, the face-centered cubic (f.c.c.) Ag gradually transforms first to a trigonal Ag 2 CO 3 phase, followed by the formation of a monoclinic Ag 2 CO 3 phase. A reducing potential immediately reverts the structure to the Ag (f.c.c.) phase. Following the electrochemical-reaction-induced phase transitions is of fundamental interest and necessary for understanding and improving the stability of electrocatalysts, and the operando cell proves a versatile setup for probing this. In addition, it is demonstrated that, when studying electrochemical reactions, a high energy or short exposure time is needed to circumvent beam-induced effects.

Frank, Sara (ORCID:0000000163218363)↗
DOE OSTI2021

Templated Mesoporous Silica Outer Shell for Controlled Silver Release of a Magnetically Recoverable and Reusable Nanocomposite for Water Disinfection

Here, we encapsulated Fe 3 O 4 @SiO 2 @Ag (MS-Ag), a bifunctional magnetic silver core–shell structure, with an outer mesoporous silica (mS) shell to form an Fe 3 O 4 @SiO 2 @ 2 Ag@mSiO 2 (MS-Ag-mS) nanocomposite using a cationic CTAB (cetyltrimethylammonium bromide) micelle templating strategy. The mS shell acts as protection to slow down the oxidation and detachment of the AgNPs and incorporates channels to control the release of antimicrobial Ag + ions. Results of TEM, STEM, HRSEM, EDS, BET, and FTIR showed the successful formation of the mS shells on MS-Ag aggregates 50–400 nm in size with highly uniform pores ~4 nm in diameter that were separated by silica walls ~2 nm thick. Additionally, the mS shell thickness was tuned to demonstrate controlled Ag + release; an increase in shell thickness resulted in an increased path length required for Ag + ions to travel out of the shell, reducing MS-Ag-mS’ ability to inhibit E. coli growth as illustrated by the inhibition zone results. Through a shaking test, the MS-Ag-mS nanocomposite was shown to eradicate 99.99+% of a suspension of E. coli at 1 × 10 6 CFU/mL with a silver release of less than 0.1 ppb, well under the EPA recommendation of 0.1 ppm. This high biocidal efficiency with minimal silver leach is ascribed to the nanocomposite’s mS shell surface characteristics, including having hydroxyl groups and possessing a high degree of structural periodicity at the nanoscale or “smoothness” that encourages association with bacteria and retains high Ag + concentration on its surface and in its close proximity. Furthermore, the nanocomposite demonstrated consistent antimicrobial performance and silver release levels over multiple repeated uses (after being recovered magnetically because of the oxidation-resistant silica-coated magnetic Fe 3 O 4 core). It also proved effective at killing all microbes from Long Island Sound surface water. The described MS-Ag-mS nanocomposite is highly synergistic, easy to prepare, and readily recoverable and reusable and offers structural tunability affecting the bioavailability of Ag + , making it excellent for water disinfection that will find wide applications.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2025

Reversible CO 2 Hydrogenation, Neutron Crystallography, and Hydride Reactivity of a Triiridium Heptahydride Complex

Abstract The authors report the structure, reactivity, and catalytic utility of a triiridium complex, [Ir 3 H 6 ( μ 3 ‐H)(PN) 3 ] 2+ ( 2‐H , PN = (2‐pyridyl)CH 2 PBu t 2 ). Despite its unusual stability to unsaturated organics, electrophiles, and even CF 3 SO 3 D, they find that complex 2‐H catalyzes hydrogenation of CO 2 to formate (TON Ir = 9600) and reverse formic acid dehydrogenation (TON Ir = 54 400). The hydrogenation operates via a reactive intermediate [Ir 3 H 4 ( μ ‐H) 4 (PN) 3 ] + ( 5 ). Neutron crystallography and DFT‐supported neutron vibrational spectroscopy of 2‐H reveal Ir─H bond lengths and elucidate the vibration modes within the Ir 3 H 7 core. Stoichiometric oxidation of 2‐H produces four classes of iridium complexes of varied nuclearity and hydride structure: tetra‐ and pentanuclear clusters [Ir 3 H 6 ( μ 3 ‐AuPPh 3 )(PN) 3 ] 2+ ( 2‐Au ) and [Ag{Ir 2 H 4 ( μ ‐OAc)(PN) 2 } 2 ] 3+ ( 6 ) are generated using AuPPh 3 + and AgOAc, respectively. Further oxidation to class [Ir 2 H 3 ( μ ‐X) 2 (PN) 2 ] + is possible with AgOAc, Hg(OAc) 2 , or I 2 . Finally, a TEMPO/HCl system completely oxidizes the hydrides and gives [Ir 2 Cl 4 ( μ ‐Cl) 2 (PN) 2 ] ( 11 ).

Cherepakhin, Valeriy [Loker Hydrocarbon Research I↗
DOE OSTI2020

Materials Data on Ag3P2N(O3F)2 by Materials Project

Ag3P2N(O3F)2 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are seven inequivalent Ag+2.33+ sites. In the first Ag+2.33+ site, Ag+2.33+ is bonded in a 5-coordinate geometry to four O2- and one F1- atom. There are a spread of Ag–O bond distances ranging from 2.21–2.72 Å. The Ag–F bond length is 2.93 Å. In the second Ag+2.33+ site, Ag+2.33+ is bonded in a 5-coordinate geometry to four O2- and one F1- atom. There are a spread of Ag–O bond distances ranging from 2.21–2.72 Å. The Ag–F bond length is 2.95 Å. In the third Ag+2.33+ site, Ag+2.33+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are two shorter (2.37 Å) and two longer (2.40 Å) Ag–O bond lengths. In the fourth Ag+2.33+ site, Ag+2.33+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are two shorter (2.36 Å) and two longer (2.42 Å) Ag–O bond lengths. In the fifth Ag+2.33+ site, Ag+2.33+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Ag–O bond distances ranging from 2.25–2.67 Å. In the sixth Ag+2.33+ site, Ag+2.33+ is bonded to four O2- atoms to form distorted AgO4 trigonal pyramids that share corners with four PO3F tetrahedra and corners with two equivalent AgO4 trigonal pyramids. There are a spread of Ag–O bond distances ranging from 2.24–2.65 Å. In the seventh Ag+2.33+ site, Ag+2.33+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ag–O bond distances ranging from 2.33–2.86 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to three O2- and one F1- atom to form PO3F tetrahedra that share a cornercorner with one AgO4 trigonal pyramid. There is two shorter (1.53 Å) and one longer (1.54 Å) P–O bond length. The P–F bond length is 1.59 Å. In the second P5+ site, P5+ is bonded to three O2- and one F1- atom to form PO3F tetrahedra that share corners with three equivalent AgO4 trigonal pyramids. There is two shorter (1.53 Å) and one longer (1.54 Å) P–O bond length. The P–F bond length is 1.59 Å. In the third P5+ site, P5+ is bonded in a tetrahedral geometry to three O2- and one F1- atom. There is two shorter (1.53 Å) and one longer (1.55 Å) P–O bond length. The P–F bond length is 1.59 Å. In the fourth P5+ site, P5+ is bonded in a tetrahedral geometry to three O2- and one F1- atom. There is two shorter (1.53 Å) and one longer (1.55 Å) P–O bond length. The P–F bond length is 1.59 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a 7-coordinate geometry to four O2- and three F1- atoms. There are a spread of N–O bond distances ranging from 2.94–3.10 Å. There are a spread of N–F bond distances ranging from 3.11–3.20 Å. In the second N3- site, N3- is bonded in a 8-coordinate geometry to four O2- and four F1- atoms. There are a spread of N–O bond distances ranging from 3.01–3.08 Å. There are a spread of N–F bond distances ranging from 3.08–3.26 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Ag+2.33+, one P5+, and one N3- atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Ag+2.33+, one P5+, and one N3- atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Ag+2.33+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Ag+2.33+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two Ag+2.33+, one P5+, and one N3- atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to two Ag+2.33+, one P5+, and one N3- atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ag+2.33+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ag+2.33+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to two Ag+2.33+, one P5+, and one N3- atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to two Ag+2.33+, one P5+, and one N3- atom. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to two Ag+2.33+, one P5+, and one N3- atom. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to two Ag+2.33+, one P5+, and one N3- atom. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Ag+2.33+, one P5+, and two N3- atoms. In the second F1- site, F1- is bonded in a single-bond geometry to one Ag+2.33+, one P5+, and one N3- atom. In the third F1- site, F1- is bonded in a single-bond geometry to one P5+ and two equivalent N3- atoms. In the fourth F1- site, F1- is bonded in a single-bond geometry to one P5+ and two equivalent N3- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2021

AGR-5/6/7 Irradiation As Run Predictions Using PARFUME

The PARticle FUel ModEl (PARFUME), a fuel performance modeling code used for high-temperature gas-cooled reactors, was used to model the Advanced Gas Reactor (AGR)-5/6/7 irradiation test using as-run physics and thermal data. The AGR-5/6/7 irradiation test consists of the combined fifth, sixth, and seventh planned irradiations of the AGR Fuel Development and Qualification Program. The AGR-5/6/7 test train is a multi-capsule, instrumented experiment that is designed for irradiation in the 133.4-mm diameter northeast flux trap position of the Advanced Test Reactor (ATR) at Idaho National Laboratory. Each capsule contains compacts filled with uranium oxycarbide unaltered fuel particles. This report documents the calculations performed to predict the failure probability of tristructural isotropic (TRISO)-coated fuel particles during the AGR-5/6/7 experiment. In addition, this report documents the calculated fission product release fraction from the fuel. The calculations include modeling of the AGR 5/6/7 irradiation that occurred from February 2018 to July 2020 over nine ATR cycles, including six normal cycles and three power axial locator mechanism cycles, for a total of approximately 376 effective full power days (EFPD). The irradiation conditions and material properties of the AGR-5/6/7 test predicted zero fuel particle failures in Capsules 1, 3, and 4. Fuel particle failures were predicted in two of the compacts in Capsule 2 and one particle failure is predicted in each one of the compacts in Capsule 5. All compacts that exhibited fuel particle failures predicted by PARFUME were caused by localized stress concentrations in the silicon carbide (SiC) layer caused by cracking in the inner pyrolytic (IPyC) layer. In addition, shrinkage of the buffer and IPyC layer during irradiation resulted in formation of a buffer-IPyC gap. Compacts with a lower irradiation temperature and fluence experienced the smallest buffer-IPyC gap formation. Conversely, higher irradiated temperature compacts with a high fluence experienced the largest buffer-IPyC gap formation. Compact 3-6-3 experienced the largest buffer IPyC gap formation of just under 21.7 µm. The release fraction of fission products silver (Ag), cesium (Cs), and strontium (Sr) vary depending on capsule location and irradiation temperature. The maximum release fraction of Ag occurs in Capsule 3, reaching up to 59.5% for the TRISO fuel particles (compact 3-6-3). The release fraction of the other two fission products, Cs and Sr, are much smaller. A maximum Cs release fraction of 1.1% occurred in compact 3-4-3 and 4.4% for Sr in compact 3-6-3.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Reversible CO 2 Hydrogenation, Neutron Crystallography, and Hydride Reactivity of a Triiridium Heptahydride Complex

Here, the authors report the structure, reactivity, and catalytic utility of a triiridium complex, [Ir 3 H 6 (μ 3 -H)(PN) 3 ] 2+ (2-H, PN = (2-pyridyl)CH 2 PBu t 2 ). Despite its unusual stability to unsaturated organics, electrophiles, and even CF 3 SO 3 D, they find that complex 2-H catalyzes hydrogenation of CO 2 to formate (TON Ir = 9600) and reverse formic acid dehydrogenation (TON Ir = 54 400). The hydrogenation operates via a reactive intermediate [Ir 3 H 4 (μ-H) 4 (PN) 3 ] + (5). Neutron crystallography and DFT-supported neutron vibrational spectroscopy of 2-H reveal Ir─H bond lengths and elucidate the vibration modes within the Ir 3 H 7 core. Stoichiometric oxidation of 2-H produces four classes of iridium complexes of varied nuclearity and hydride structure: tetra- and pentanuclear clusters [Ir 3 H 6 (μ 3 -AuPPh 3 )(PN) 3 ] 2+ (2-Au) and [Ag{Ir 2 H 4 (μ-OAc)(PN) 2 } 2 ] 3+ (6) are generated using AuPPh 3 + and AgOAc, respectively. Further oxidation to class [Ir 2 H 3 (μ-X) 2 (PN) 2 ] + is possible with AgOAc, Hg(OAc) 2 , or I 2 . Finally, a TEMPO/HCl system completely oxidizes the hydrides and gives [Ir 2 Cl 4 (μ-Cl) 2 (PN) 2 ] (11).

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

Materials Data on Li3Ag3Sn2 by Materials Project

LiAg2Li2AgSn2 crystallizes in the trigonal R3m space group. The structure is three-dimensional and consists of three LiAg2 sheets oriented in the (0, 0, 1) direction and one Li2AgSn2 framework. In each LiAg2 sheet, Li is bonded to four Ag atoms to form distorted corner-sharing LiAg4 tetrahedra. There are one shorter (2.85 Å) and three longer (2.88 Å) Li–Ag bond lengths. There are two inequivalent Ag sites. In the first Ag site, Ag is bonded in a 3-coordinate geometry to three equivalent Li atoms. In the second Ag site, Ag is bonded in a distorted single-bond geometry to one Li atom. In the Li2AgSn2 framework, there are two inequivalent Li sites. In the first Li site, Li is bonded in a 5-coordinate geometry to one Ag and four Sn atoms. The Li–Ag bond length is 2.86 Å. There are one shorter (2.86 Å) and three longer (2.87 Å) Li–Sn bond lengths. In the second Li site, Li is bonded in a 7-coordinate geometry to three equivalent Ag and four Sn atoms. All Li–Ag bond lengths are 2.88 Å. There are one shorter (2.88 Å) and three longer (2.90 Å) Li–Sn bond lengths. Ag is bonded to four Li atoms to form distorted AgLi4 tetrahedra that share corners with four equivalent SnLi4 tetrahedra, corners with six equivalent AgLi4 tetrahedra, and edges with three equivalent SnLi4 tetrahedra. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 4-coordinate geometry to four Li atoms. In the second Sn site, Sn is bonded to four Li atoms to form distorted SnLi4 tetrahedra that share corners with four equivalent AgLi4 tetrahedra, corners with six equivalent SnLi4 tetrahedra, and edges with three equivalent AgLi4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Role of Zeolite Structural Properties toward Iodine Capture: A Head-to-head Evaluation of Framework Type and Chemical Composition

This study evaluated zeolite-based sorbents for iodine gas [I2(g)] capture. Based on the framework structures and porosities, five zeolites, including two faujasite (FAU), one ZSM-5 (MFI), one mesoMFI, one ZSM-22 (TON), as well as two mesoporous materials, were evaluated for I2(g) capture at room temperature and 150 °C in an iodine-saturated environment. From these preliminary studies, the three best-performing zeolites were ion-exchanged with Ag+ and evaluated for I2(g) capture under similar conditions. Energy-dispersive X-ray spectroscopy data suggest that Ag-FAU frameworks were the materials with the highest capacity for I2(g) in this study, showing ~3× higher adsorption compared to Ag-mordenite (Ag-MOR) at room temperature, but X-ray diffraction measurements show that the faujasite structure collapsed during the adsorption studies because of dealumination. The Ag-MFI zeolites are decent sorbents in real-life applications, showing both good sorption capacities and higher stability. In-depth analyses and characterizations, including synchrotron X-ray absorption spectroscopy, revealed the influence of structural and chemical properties of zeolites on the performance for iodine adsorption from the gas phase.

aluminosilicate zeolites, iodine, porosity, acidit↗
DOE OSTI2020

Materials Data on Ag7(SI)2 by Materials Project

Ag7(SI)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are seven inequivalent Ag sites. In the first Ag site, Ag is bonded to three equivalent Ag and three equivalent I atoms to form distorted AgAg3I3 octahedra that share corners with three equivalent IAg4 trigonal pyramids and edges with six equivalent AgAg3I3 octahedra. There are a spread of Ag–Ag bond distances ranging from 2.88–3.06 Å. There are a spread of Ag–I bond distances ranging from 2.95–3.17 Å. In the second Ag site, Ag is bonded in a distorted linear geometry to one S and one I atom. The Ag–S bond length is 2.41 Å. The Ag–I bond length is 2.68 Å. In the third Ag site, Ag is bonded in a 4-coordinate geometry to one S and three equivalent I atoms. The Ag–S bond length is 2.53 Å. There are a spread of Ag–I bond distances ranging from 2.82–3.10 Å. In the fourth Ag site, Ag is bonded in a distorted single-bond geometry to three equivalent Ag and one I atom. The Ag–I bond length is 2.81 Å. In the fifth Ag site, Ag is bonded in a linear geometry to two S atoms. There are one shorter (2.42 Å) and one longer (2.47 Å) Ag–S bond lengths. In the sixth Ag site, Ag is bonded in a bent 150 degrees geometry to two equivalent S atoms. There are one shorter (2.43 Å) and one longer (2.44 Å) Ag–S bond lengths. In the seventh Ag site, Ag is bonded in a 3-coordinate geometry to three equivalent S atoms. There are a spread of Ag–S bond distances ranging from 2.51–2.67 Å. There are two inequivalent S sites. In the first S site, S is bonded in a distorted see-saw-like geometry to four Ag atoms. In the second S site, S is bonded in a distorted pentagonal planar geometry to five Ag atoms. There are two inequivalent I sites. In the first I site, I is bonded to four Ag atoms to form distorted IAg4 trigonal pyramids that share corners with three equivalent AgAg3I3 octahedra and corners with six equivalent IAg4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 58–63°. In the second I site, I is bonded in a rectangular see-saw-like geometry to four Ag atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Screen-Printed Complex Ag Inks for Si HJT Metallization

Metallization using reactive metal inks has recently attracted significant research interest due to its advantages in cost of materials and manufacturing, while still achieving performance comparable to traditional fire-through particle pastes. Here, we present for the first time the use of reactive silver (Ag) inks via industrial screen-printing and inkjet printing methods for the metallization of different Si surfaces used in tunneling oxide passivating contacts (TOPCon) and Silicon heterojunction (SHJ) solar cells. Printed Ag lines exhibit a conductivity of ~5 Mu O·cm, which is approximately 3 times that of bulk Ag (1.59 µO·cm). The printed metal has a thickness of ~0.5-1.5 Mu m, an order of magnitude smaller than the current fire-through metal finger thickness (~15 Mu m). Contact resistivity measurements of the screen-printed and inkjet-printed samples on a transparent conducting oxide (TCO) surface show a very low value of ~0.2-12 mO·cm 2. Photoluminescence images of the metallized samples demonstrate minimal surface passivation degradation compared to the non-metallized areas (?iVoc <3.5 mV). Scanning electron microscopy images (SEM) reveal the structure of the printed metals on the Si surfaces as porous but much denser than fire-through Ag by nanoparticle paste. In the final presentation, we will showcase our results of printing these reactive Ag inks on high-efficiency heterojunction and TOPCon solar cells with full-area M6 wafers. Additionally, the adhesion of these reactive Ag inks on different Si surfaces according to ASTM D3359-17, as well as the performance of solar cells after standard IEC 61215 freeze/thaw and damp heat tests, will be presented. These new metal inks show promising potential as an alternative to the currently dominant particle-based pastes, offering lower Ag consumption and lower processing temperatures without compromising performance.

heterojunction solar cells↗
DOE OSTI2020

Materials Data on Na8Al11Si13(AgO16)3 by Materials Project

NaNa7Al11Si13(AgO16)3 crystallizes in the triclinic P1 space group. The structure is three-dimensional and consists of one sodium molecule and one Na7Al11Si13(AgO16)3 framework. In the Na7Al11Si13(AgO16)3 framework, there are seven inequivalent Na sites. In the first Na site, Na is bonded in a 6-coordinate geometry to four O atoms. There are a spread of Na–O bond distances ranging from 2.33–2.45 Å. In the second Na site, Na is bonded in a distorted trigonal planar geometry to three O atoms. There are a spread of Na–O bond distances ranging from 2.21–2.35 Å. In the third Na site, Na is bonded in a distorted L-shaped geometry to two O atoms. There are one shorter (2.17 Å) and one longer (2.18 Å) Na–O bond lengths. In the fourth Na site, Na is bonded in a 3-coordinate geometry to three O atoms. There are a spread of Na–O bond distances ranging from 2.17–2.44 Å. In the fifth Na site, Na is bonded in a 3-coordinate geometry to four O atoms. There are a spread of Na–O bond distances ranging from 2.18–2.87 Å. In the sixth Na site, Na is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Na–O bond distances ranging from 2.23–2.82 Å. In the seventh Na site, Na is bonded in a distorted pentagonal planar geometry to five O atoms. There are a spread of Na–O bond distances ranging from 2.29–2.78 Å. There are three inequivalent Ag sites. In the first Ag site, Ag is bonded in a 3-coordinate geometry to one Ag and four O atoms. The Ag–Ag bond length is 2.81 Å. There are a spread of Ag–O bond distances ranging from 2.32–2.69 Å. In the second Ag site, Ag is bonded in a distorted trigonal planar geometry to one Ag and three O atoms. The Ag–Ag bond length is 2.76 Å. There are a spread of Ag–O bond distances ranging from 2.32–2.47 Å. In the third Ag site, Ag is bonded in a water-like geometry to two Ag atoms. There are eleven inequivalent Al sites. In the first Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.73–1.78 Å. In the second Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.72–1.81 Å. In the third Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.74–1.80 Å. In the fourth Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra and corners with three AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.73–1.79 Å. In the fifth Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra and corners with three AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.70–1.83 Å. In the sixth Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.72–1.76 Å. In the seventh Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.71–1.79 Å. In the eighth Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.70–1.83 Å. In the ninth Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.74–1.82 Å. In the tenth Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.72–1.81 Å. In the eleventh Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.69–1.83 Å. There are thirteen inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.68 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There is two shorter (1.60 Å) and two longer (1.66 Å) Si–O bond length. In the fifth Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the sixth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.69 Å. In the seventh Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra and corners with three AlO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the eighth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. In the ninth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. In the tenth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.63–1.65 Å. In the eleventh Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There is one shorter (1.63 Å) and three longer (1.65 Å) Si–O bond length. In the twelfth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the thirteenth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.68 Å. There are forty-eight inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the third O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fourth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fifth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the sixth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the seventh O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the eighth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to one Ag and two Si atoms. In the tenth O site, O is bonded in a distorted bent 150 degrees geometry to one Ag, one Al, and one Si atom. In the eleventh O site, O is bonded in a distorted bent 150 degrees geometry to one Ag and two Si atoms. In the twelfth O site, O is bonded in a distorted bent 150 degrees geometry to one Na and two Si atoms. In the thirteenth O site, O is bonded in a 2-coordinate geometry to one Ag, one Al, and one Si atom. In the fourteenth O site, O is bonded in a distorted bent 150 degrees geometry to one Na and two Si atoms. In the fifteenth O site, O is bonded in a 3-coordinate geometry to one Na and two Si atoms. In the sixteenth O site, O is bonded in a distorted bent 150 degrees geometry to one Na and two Si atoms. In the seventeenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the eighteenth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the nineteenth O site, O is bonded in a linear geometry to two Si atoms. In the twentieth O site, O is bonded in a distorted bent 150 degrees geometry to one Ag, one Al, and one Si atom. In the twenty-first O site, O is bonded in a linear geometry to one Al and one Si atom. In the twenty-second O site, O is bonded in a 2-coordinate geometry to one Na, one Al, and one Si atom. In the twenty-third O site, O is bonded in a distorted bent 150 degrees geometry to one Ag and two Si atoms. In the twenty-fourth O site, O is bonded in a 2-coordinate geometry to one Ag, one Al, and one Si atom. In the twenty-fifth O site, O is bonded in a 2-coordinate geometry to one Na, one Al, and one Si atom. In the twenty-sixth O site, O is bonded in a distorted trigonal planar geometry to one Na and two Al atoms. In the twenty-seventh O site, O is bonded in a distorted bent 150 degrees geometry to one Al and one Si atom. In the twenty-eighth O site, O is bonded in a 3-coordinate geometry to one Na, one Al, and one Si atom. In the twenty-ninth O site, O is bonded in a bent 150 degrees geometry to two Al atoms. In the thirtieth O site, O is bonded in a 2-coordinate geometry to one Na and two Al atoms. In the thirty-first O site, O is bonded in a distorted trigonal non-coplanar geometry to one Na and two Al atoms. In the thirty-second O site, O is bonded in a 3-coordinate geometry to one Na and two Al atoms. In the thirty-third O site, O is bonded in a 3-coordinate geometry to one Na and two Al atoms. In the thirty-fourth O site, O is bonded in a bent 150 degrees geometry to two Al atoms. In the thirty-fifth O site, O is bonded in a distorted bent 150 degrees geometry to one Na and two Al atoms. In the thirty-sixth O site, O is bonded in a distorted bent 150 degrees geometry to one Na and two Al atoms. In the thirty-seventh O site, O is bonded in a 5-coordinate geometry to three Na and two Al atoms. In the thirty-eighth O site, O is bonded in a distorted see-saw-like geometry to two Na and two Al atoms. In the thirty-ninth O site, O is bonded in a bent 150 degrees geometry to two Al atoms. In the fortieth O site, O is bonded in a 2-coordinate geometry to one Na and two Al atoms. In the forty-first O site, O is bonded in a distorted trigonal planar geometry to one Na, one Al, and one Si atom. In the forty-second O site, O is bonded in a distorted trigonal planar geometry to one Na, one Al, and one Si atom. In the forty-third O site, O is bonded in a 2-coordinate geometry to one Na, one Al, and one Si atom. In the forty-fourth O site, O is bonded in a distorted bent 150 degrees geometry to one Na, one Al, and one Si atom. In the forty-fifth O site, O is bonded in a 2-coordinate geometry to one Na, one Al, and one Si atom. In the forty-sixth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the forty-seventh O site, O is bonded in a 3-coordinate geometry to one Na, one Al, and one Si atom. In the forty-eighth O site, O is bonded in a bent 120 degrees geometry to one Al and one Si atom.

36 MATERIALS SCIENCE↗