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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on KU11(GeO19)2 by Materials Project

KU11(GeO19)2 crystallizes in the trigonal P-31c space group. The structure is three-dimensional. K is bonded in a 6-coordinate geometry to six equivalent O atoms. All K–O bond lengths are 2.85 Å. There are three inequivalent U sites. In the first U site, U is bonded to seven O atoms to form distorted UO7 pentagonal bipyramids that share corners with two equivalent UO6 octahedra, corners with two equivalent UO7 pentagonal bipyramids, corners with two equivalent GeO4 tetrahedra, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 32°. There are a spread of U–O bond distances ranging from 1.80–2.54 Å. In the second U site, U is bonded to six O atoms to form a mixture of edge and corner-sharing UO6 octahedra. There are three shorter (2.07 Å) and three longer (2.13 Å) U–O bond lengths. In the third U site, U is bonded to seven O atoms to form distorted UO7 pentagonal bipyramids that share a cornercorner with one UO6 octahedra, corners with two equivalent UO7 pentagonal bipyramids, a cornercorner with one GeO4 tetrahedra, an edgeedge with one UO6 octahedra, and edges with two UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 35°. There are a spread of U–O bond distances ranging from 1.81–2.49 Å. Ge is bonded to four O atoms to form GeO4 tetrahedra that share corners with six UO7 pentagonal bipyramids and a cornercorner with one GeO4 tetrahedra. There is one shorter (1.73 Å) and three longer (1.77 Å) Ge–O bond length. There are eight inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to two equivalent U atoms. In the second O site, O is bonded in a trigonal planar geometry to three equivalent U atoms. In the third O site, O is bonded in a distorted single-bond geometry to one K and one U atom. In the fourth O site, O is bonded in a single-bond geometry to one U atom. In the fifth O site, O is bonded in a distorted trigonal planar geometry to two U and one Ge atom. In the sixth O site, O is bonded in a distorted trigonal non-coplanar geometry to three U atoms. In the seventh O site, O is bonded in a linear geometry to two equivalent Ge atoms. In the eighth O site, O is bonded in a 3-coordinate geometry to three U atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsRbMg14O15 by Materials Project

CsRbMg14O15 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. Cs1+ is bonded in a 8-coordinate geometry to four O2- atoms. There are two shorter (2.44 Å) and two longer (2.52 Å) Cs–O bond lengths. Rb1+ is bonded to five O2- atoms to form distorted RbO5 trigonal bipyramids that share corners with three MgO6 octahedra, corners with two equivalent MgO5 square pyramids, corners with two equivalent RbO5 trigonal bipyramids, and edges with four equivalent MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–62°. There are four shorter (2.40 Å) and one longer (2.47 Å) Rb–O bond lengths. There are ten inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, a cornercorner with one RbO5 trigonal bipyramid, corners with two equivalent MgO5 trigonal bipyramids, edges with six MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 3°. There are a spread of Mg–O bond distances ranging from 1.93–2.45 Å. In the second Mg2+ site, Mg2+ is bonded to five O2- atoms to form MgO5 trigonal bipyramids that share corners with two equivalent MgO6 octahedra, corners with two equivalent MgO5 trigonal bipyramids, and edges with six MgO6 octahedra. The corner-sharing octahedral tilt angles are 20°. There are a spread of Mg–O bond distances ranging from 1.95–2.14 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six MgO6 octahedra, a cornercorner with one MgO5 square pyramid, edges with two MgO6 octahedra, and edges with two equivalent RbO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 4–26°. There are a spread of Mg–O bond distances ranging from 2.13–2.65 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with four MgO6 octahedra, an edgeedge with one MgO5 square pyramid, and edges with two equivalent MgO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 0–18°. There are a spread of Mg–O bond distances ranging from 2.15–2.39 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, a cornercorner with one MgO5 square pyramid, corners with two equivalent RbO5 trigonal bipyramids, and edges with six MgO6 octahedra. The corner-sharing octahedral tilt angles are 9°. There are a spread of Mg–O bond distances ranging from 1.91–2.45 Å. In the sixth Mg2+ site, Mg2+ is bonded in a 3-coordinate geometry to three O2- atoms. There are one shorter (1.94 Å) and two longer (2.08 Å) Mg–O bond lengths. In the seventh Mg2+ site, Mg2+ is bonded to five O2- atoms to form MgO5 square pyramids that share corners with five MgO6 octahedra, corners with two equivalent MgO5 square pyramids, corners with two equivalent RbO5 trigonal bipyramids, and edges with four MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–79°. There are a spread of Mg–O bond distances ranging from 2.06–2.21 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with four MgO6 octahedra, and edges with two equivalent MgO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 20°. There are a spread of Mg–O bond distances ranging from 1.97–2.58 Å. In the ninth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 1.96–2.57 Å. In the tenth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 2.11–2.51 Å. There are eleven inequivalent O2- sites. In the first O2- site, O2- is bonded to five Mg2+ atoms to form OMg5 square pyramids that share corners with three ORbMg5 octahedra, corners with two equivalent OMg5 square pyramids, corners with two equivalent ORb2Mg3 trigonal bipyramids, and edges with six OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–73°. In the second O2- site, O2- is bonded to one Rb1+ and five Mg2+ atoms to form distorted ORbMg5 octahedra that share corners with two equivalent ORbMg5 octahedra, corners with three OMg5 square pyramids, corners with two equivalent ORb2Mg3 trigonal bipyramids, and edges with eight OMg6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the third O2- site, O2- is bonded to five Mg2+ atoms to form OMg5 square pyramids that share corners with four ORbMg5 octahedra, corners with two equivalent OMg5 square pyramids, corners with two equivalent OCs2Mg3 trigonal bipyramids, and edges with six OMg6 octahedra. The corner-sharing octahedra tilt angles range from 27–80°. In the fourth O2- site, O2- is bonded to six Mg2+ atoms to form distorted OMg6 octahedra that share corners with six OMg6 octahedra, a cornercorner with one OCs2Mg3 trigonal bipyramid, edges with four OMg6 octahedra, edges with two equivalent OMg5 square pyramids, and an edgeedge with one ORb2Mg3 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 0–27°. In the fifth O2- site, O2- is bonded to six Mg2+ atoms to form distorted OMg6 octahedra that share corners with six OMg6 octahedra, a cornercorner with one ORb2Mg3 trigonal bipyramid, edges with six ORbMg5 octahedra, edges with two equivalent OMg5 square pyramids, and an edgeedge with one OCs2Mg3 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 0–21°. In the sixth O2- site, O2- is bonded to two equivalent Rb1+ and three Mg2+ atoms to form distorted ORb2Mg3 trigonal bipyramids that share corners with five ORbMg5 octahedra, corners with two equivalent OMg5 square pyramids, corners with four ORb2Mg3 trigonal bipyramids, and edges with six OCsRbMg4 octahedra. The corner-sharing octahedra tilt angles range from 0–78°. In the seventh O2- site, O2- is bonded to two equivalent Cs1+ and three Mg2+ atoms to form distorted OCs2Mg3 trigonal bipyramids that share corners with three OMg6 octahedra, corners with two equivalent OMg5 square pyramids, corners with four ORb2Mg3 trigonal bipyramids, and edges with six OCsRbMg4 octahedra. The corner-sharing octahedra tilt angles range from 0–86°. In the eighth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, a cornercorner with one ORb2Mg3 trigonal bipyramid, edges with six ORbMg5 octahedra, and edges with two equivalent OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 3–5°. In the ninth O2- site, O2- is bonded to six Mg2+ atoms to form distorted OMg6 octahedra that share corners with four OMg6 octahedra, a cornercorner with one OCs2Mg3 trigonal bipyramid, edges with four OMg6 octahedra, and edges with two equivalent OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 5–14°. In the tenth O2- site, O2- is bonded to one Cs1+, one Rb1+, and four Mg2+ atoms to form distorted OCsRbMg4 octahedra that share corners with four equivalent OCsRbMg4 octahedra, corners with two OMg5 square pyramids, edges with five ORbMg5 octahedra, and edges with four ORb2Mg3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 12–60°. In the eleventh O2- site, O2- is bonded in a 5-coordinate geometry to five Mg2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf6Ga16Pd7 by Materials Project

Hf6Pd7Ga16 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Hf is bonded in a 4-coordinate geometry to four equivalent Pd and four equivalent Ga atoms. All Hf–Pd bond lengths are 3.22 Å. All Hf–Ga bond lengths are 2.83 Å. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded to four equivalent Hf and eight Ga atoms to form a mixture of distorted face and corner-sharing PdHf4Ga8 cuboctahedra. There are four shorter (2.55 Å) and four longer (2.72 Å) Pd–Ga bond lengths. In the second Pd site, Pd is bonded in a body-centered cubic geometry to eight equivalent Ga atoms. All Pd–Ga bond lengths are 2.63 Å. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded in a 6-coordinate geometry to three equivalent Hf and three equivalent Pd atoms. In the second Ga site, Ga is bonded in a 4-coordinate geometry to four Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LuIO9 by Materials Project

LuO9I crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Lu is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Lu–O bond distances ranging from 2.18–2.54 Å. There are nine inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one I atom. The O–I bond length is 1.87 Å. In the second O site, O is bonded in a water-like geometry to one Lu and one I atom. The O–I bond length is 1.85 Å. In the third O site, O is bonded in a trigonal non-coplanar geometry to two equivalent Lu and one I atom. The O–I bond length is 1.95 Å. In the fourth O site, O is bonded in a bent 120 degrees geometry to one O and one I atom. The O–O bond length is 1.32 Å. The O–I bond length is 2.49 Å. In the fifth O site, O is bonded in a water-like geometry to one Lu and one I atom. The O–I bond length is 1.86 Å. In the sixth O site, O is bonded in a distorted single-bond geometry to one Lu atom. In the seventh O site, O is bonded in a water-like geometry to one Lu and one I atom. The O–I bond length is 1.87 Å. In the eighth O site, O is bonded in a bent 120 degrees geometry to one Lu and one O atom. The O–O bond length is 1.31 Å. In the ninth O site, O is bonded in a bent 120 degrees geometry to two O atoms. I is bonded in a 6-coordinate geometry to six O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Synthesis and Properties of Bulk Mg 3 WN 4 in a Wurtzite-Derived Structure

Experimental synthesis of theoretically predicted materials with controlled elemental coordination environments can lead to the realization of useful properties, such as facile ion transport or ferroelectric switching. Among such materials are ternary nitrides in the Mg−W−N composition space, where several stable and metastable compounds have been predicted and synthesized recently in bulk and film forms. Here, we report for the first time on the bulk synthesis of Mg 3 WN 4 in a wurtzite-derived crystal structure via a solid-state metathesis reaction. In situ synchrotron powder X-ray diffraction shows how the ion exchange proceeds from Li 6 WN 4 + MgCl 2 precursors to Mg 3 WN 4 + LiCl products, with the reaction starting slowly near 380 °C and completing by 600 °C, including the presence of a competing disordered rocksalt-derived phase (Mg,W)N above 440 °C. The follow-up ex situ powder synthesis at 400 °C for 0.5 h with 10% excess MgCl 2 reveals the cation-ordered nature of the wurtzite-derived Mg 3 WN 4 structure with polar symmetry confirmed by second-harmonic generation measurements. Optical absorption spectra, chemical composition analysis, and electron microscopy imaging suggest that bulk Mg 3 WN 4 obtained via metathesis reaction is prone to defect formation. Overall, this study shows that selective ex situ synthesis of the phase-pure ternary nitrides, informed by in situ measurements, is possible by carefully controlling the thermal budget of the reaction and paves the way toward property characterization of the Mg 3 WN 4 wurtzite-derived material.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Reversible transformations between the non-porous phases of a flexible coordination network enabled by transient porosity

Abstract Flexible metal–organic materials that exhibit stimulus-responsive switching between closed (non-porous) and open (porous) structures induced by gas molecules are of potential utility in gas storage and separation. Such behaviour is currently limited to a few dozen physisorbents that typically switch through a breathing mechanism requiring structural contortions. Here we show a clathrate (non-porous) coordination network that undergoes gas-induced switching between multiple non-porous phases through transient porosity, which involves the diffusion of guests between discrete voids through intra-network distortions. This material is synthesized as a clathrate phase with solvent-filled cavities; evacuation affords a single-crystal to single-crystal transformation to a phase with smaller cavities. At 298 K, carbon dioxide, acetylene, ethylene and ethane induce reversible switching between guest-free and gas-loaded clathrate phases. For carbon dioxide and acetylene at cryogenic temperatures, phases showing progressively higher loadings were observed and characterized using in situ X-ray diffraction, and the mechanism of diffusion was computationally elucidated.

Chemistry↗
DOE OSTI2020

Materials Data on Li5Mn9(P2O7)8 by Materials Project

Li5Mn9(P2O7)8 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are five inequivalent Li sites. In the first Li site, Li is bonded in a 4-coordinate geometry to three O atoms. There are one shorter (1.93 Å) and two longer (2.07 Å) Li–O bond lengths. In the second Li site, Li is bonded in a distorted T-shaped geometry to three O atoms. There are a spread of Li–O bond distances ranging from 1.95–2.00 Å. In the third Li site, Li is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Li–O bond distances ranging from 2.05–2.29 Å. In the fourth Li site, Li is bonded in a distorted T-shaped geometry to three O atoms. There are a spread of Li–O bond distances ranging from 1.95–2.05 Å. In the fifth Li site, Li is bonded to four O atoms to form distorted LiO4 trigonal pyramids that share corners with two MnO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 74–80°. There are a spread of Li–O bond distances ranging from 1.94–2.45 Å. There are nine inequivalent Mn sites. In the first Mn site, Mn is bonded to six O atoms to form MnO6 octahedra that share a cornercorner with one MnO6 octahedra and corners with six PO4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. There are a spread of Mn–O bond distances ranging from 1.95–2.31 Å. In the second Mn site, Mn is bonded to six O atoms to form distorted MnO6 octahedra that share a cornercorner with one MnO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. There are a spread of Mn–O bond distances ranging from 1.91–2.47 Å. In the third Mn site, Mn is bonded to six O atoms to form distorted MnO6 octahedra that share a cornercorner with one MnO6 octahedra and corners with six PO4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. There are a spread of Mn–O bond distances ranging from 1.94–2.46 Å. In the fourth Mn site, Mn is bonded to six O atoms to form distorted MnO6 octahedra that share a cornercorner with one MnO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There are a spread of Mn–O bond distances ranging from 1.89–2.56 Å. In the fifth Mn site, Mn is bonded in a 4-coordinate geometry to six O atoms. There are a spread of Mn–O bond distances ranging from 1.94–2.53 Å. In the sixth Mn site, Mn is bonded to six O atoms to form distorted MnO6 octahedra that share a cornercorner with one MnO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. There are a spread of Mn–O bond distances ranging from 1.89–2.48 Å. In the seventh Mn site, Mn is bonded to six O atoms to form distorted MnO6 octahedra that share a cornercorner with one MnO6 octahedra and corners with six PO4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There are a spread of Mn–O bond distances ranging from 1.93–2.46 Å. In the eighth Mn site, Mn is bonded to six O atoms to form distorted MnO6 octahedra that share a cornercorner with one MnO6 octahedra, corners with four PO4 tetrahedra, a cornercorner with one LiO4 trigonal pyramid, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. There are a spread of Mn–O bond distances ranging from 1.91–2.47 Å. In the ninth Mn site, Mn is bonded to six O atoms to form MnO6 octahedra that share a cornercorner with one MnO6 octahedra, corners with six PO4 tetrahedra, and a cornercorner with one LiO4 trigonal pyramid. The corner-sharing octahedral tilt angles are 63°. There are a spread of Mn–O bond distances ranging from 1.93–2.23 Å. There are sixteen inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–51°. There are a spread of P–O bond distances ranging from 1.51–1.64 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra, a cornercorner with one PO4 tetrahedra, a cornercorner with one LiO4 trigonal pyramid, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedra tilt angles range from 40–57°. There are a spread of P–O bond distances ranging from 1.52–1.61 Å. In the third P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–47°. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. In the fourth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–54°. There are a spread of P–O bond distances ranging from 1.52–1.61 Å. In the fifth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 43–54°. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the sixth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra, a cornercorner with one PO4 tetrahedra, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedra tilt angles range from 45–57°. There are a spread of P–O bond distances ranging from 1.52–1.61 Å. In the seventh P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–56°. There are a spread of P–O bond distances ranging from 1.51–1.60 Å. In the eighth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–54°. There are a spread of P–O bond distances ranging from 1.53–1.62 Å. In the ninth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–50°. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. In the tenth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–56°. There are a spread of P–O bond distances ranging from 1.51–1.60 Å. In the eleventh P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one LiO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 43–54°. There are a spread of P–O bond distances ranging from 1.50–1.62 Å. In the twelfth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra, a cornercorner with one PO4 tetrahedra, a cornercorner with one LiO4 trigonal pyramid, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedra tilt angles range from 43–57°. There are a spread of P–O bond distances ranging from 1.52–1.61 Å. In the thirteenth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–55°. There are a spread of P–O bond distances ranging from 1.52–1.61 Å. In the fourteenth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three MnO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–48°. There are a spread of P–O bond distances ranging from 1.51–1.62 Å. In the fifteenth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra, a cornercorner with one PO4 tetrahedra, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedra tilt angles range from 39–57°. There are a spread of P–O bond distances ranging from 1.52–1.61 Å. In the sixteenth P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two MnO6 octahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one LiO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 45–50°. There are a spread of P–O bond distances ranging from 1.51–1.64 Å. There are fifty-six inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to one Li, one Mn, and one P atom. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Mn and one P atom. In the third O site, O is bonded in a distorted T-shaped geometry to two Li and one P atom. In the fourth O site, O is bonded in a 2-coordinate geometry to two Mn and one P atom. In the fifth O site, O is bonded in a distorted water-like geometry to one Mn and one P atom. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Mn and one P atom. In the seventh O site, O is bonded in a bent 150 degrees geometry to one Mn and one P atom. In the eighth O site, O is bonded in a 3-coordinate geometry to one Li, one Mn, and one P atom. In the ninth O site, O is bonded in a distorted trigonal planar geometry to one Li, one Mn, and one P atom. In the tenth O site, O is bonded in a distorted bent 120 degrees geometry to two P atoms. In the eleventh O site, O is bonded in a 3-coordinate geometry to two Li and one P atom. In the twelfth O site, O is bonded in a distorted bent 150 degrees geometry to one Mn and one P atom. In the thirteenth O site, O is bonded in a distorted bent 120 degrees geometry to two P atoms. In the fourteenth O site, O is bonded in a distorted trigonal planar geometry to one Li, one Mn, and one P atom. In the fifteenth O site, O is bonded in a bent 150 degrees geometry to one Mn and one P atom. In the sixteenth O site, O is bonded in a bent 150 degrees geometry to one Mn and one P atom. In the seventeenth O site, O is bonded in a bent 120 degrees geometry to two P atoms. In the eighteenth O site, O is bonded in a distorted bent 150 degrees geometry to one Mn and one P atom. In the nineteenth O site, O is bonded in a bent 150 degrees geometry to one Mn and one P atom. In the twentieth O site, O is bonded in a distorted trigonal planar geometry to two Mn and one P atom. In the twenty-first O site, O is bonded in a 2-coordinate geometry to two Mn and one P atom. In the twenty-second O site, O is bonded in a distorted bent 150 degrees geometry to one Mn and one P atom. In the twenty-third O site, O is bonded in a bent 150 degrees geometry to one Mn and one P atom. In the twenty-fourth O site, O is bonded in a bent 150 degrees geometry to one Mn and one P atom. In the twenty-fifth O site, O is bonded in a 2-coordinate geometry to two Mn and one P atom. In the twenty-sixth O site, O is bonded in a water-like geometry to one Mn and one P atom. In the twenty-seventh O site, O is bonded in a bent 120 degrees geometry to two P atoms. In the twenty-eighth O site, O is bonded in a 2-coordinate geometry to two Mn and one P atom. In the twenty-ninth O site, O is bonded in a 2-coordinate geometry to two Mn and one P atom. In the thirtieth O site, O is bonded in a bent 120 degrees geometry to two P atoms. In the thirty-first O site, O is bonded in a water-like geometry to one Mn and one P atom. In the thirty-second O site, O is bonded in a distorted bent 150 degrees geometry to one Mn and one P atom. In the thirty-third O site, O is bonded in a 2-coordinate geometry

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li4V2Si(PO6)2 by Materials Project

Li4V2Si(PO6)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.74 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share a cornercorner with one SiO4 tetrahedra, corners with five PO4 tetrahedra, and faces with two VO6 octahedra. There are a spread of Li–O bond distances ranging from 2.09–2.35 Å. In the third Li1+ site, Li1+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.05–2.81 Å. In the fourth Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share a cornercorner with one SiO4 tetrahedra, corners with five PO4 tetrahedra, and faces with two VO6 octahedra. There are a spread of Li–O bond distances ranging from 2.09–2.36 Å. In the fifth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.06–2.76 Å. In the sixth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.09–2.71 Å. In the seventh Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.06–2.79 Å. In the eighth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.09–2.72 Å. In the ninth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.05–2.78 Å. In the tenth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.06–2.74 Å. In the eleventh Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.75 Å. In the twelfth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.04–2.78 Å. In the thirteenth Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with three SiO4 tetrahedra, corners with three PO4 tetrahedra, and faces with two VO6 octahedra. There are a spread of Li–O bond distances ranging from 2.10–2.33 Å. In the fourteenth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.06–2.75 Å. In the fifteenth Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with three SiO4 tetrahedra, corners with three PO4 tetrahedra, and faces with two VO6 octahedra. There are a spread of Li–O bond distances ranging from 2.10–2.33 Å. In the sixteenth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.75 Å. There are eight inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to six O2- atoms to form VO6 octahedra that share a cornercorner with one SiO4 tetrahedra, corners with five PO4 tetrahedra, and a faceface with one LiO6 octahedra. There are a spread of V–O bond distances ranging from 1.92–2.09 Å. In the second V3+ site, V3+ is bonded to six O2- atoms to form VO6 octahedra that share corners with three SiO4 tetrahedra, corners with three PO4 tetrahedra, and a faceface with one LiO6 octahedra. There are a spread of V–O bond distances ranging from 1.94–2.10 Å. In the third V3+ site, V3+ is bonded to six O2- atoms to form VO6 octahedra that share a cornercorner with one SiO4 tetrahedra, corners with five PO4 tetrahedra, and a faceface with one LiO6 octahedra. There are a spread of V–O bond distances ranging from 1.92–2.09 Å. In the fourth V3+ site, V3+ is bonded to six O2- atoms to form VO6 octahedra that share corners with two SiO4 tetrahedra, corners with four PO4 tetrahedra, and a faceface with one LiO6 octahedra. There are a spread of V–O bond distances ranging from 1.94–2.09 Å. In the fifth V3+ site, V3+ is bonded to six O2- atoms to form VO6 octahedra that share corners with three SiO4 tetrahedra, corners with three PO4 tetrahedra, and a faceface with one LiO6 octahedra. There are a spread of V–O bond distances ranging from 1.94–2.11 Å. In the sixth V3+ site, V3+ is bonded to six O2- atoms to form VO6 octahedra that share corners with two SiO4 tetrahedra, corners with four PO4 tetrahedra, and a faceface with one LiO6 octahedra. There are a spread of V–O bond distances ranging from 1.94–2.08 Å. In the seventh V3+ site, V3+ is bonded to six O2- atoms to form VO6 octahedra that share corners with two SiO4 tetrahedra, corners with four PO4 tetrahedra, and a faceface with one LiO6 octahedra. There are a spread of V–O bond distances ranging from 1.94–2.10 Å. In the eighth V3+ site, V3+ is bonded to six O2- atoms to form VO6 octahedra that share corners with two SiO4 tetrahedra, corners with four PO4 tetrahedra, and a faceface with one LiO6 octahedra. There are a spread of V–O bond distances ranging from 1.94–2.10 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 31–45°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 30–44°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 30–44°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 31–45°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. There are eight inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 30–45°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 30–47°. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 30–45°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 30–46°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 30–47°. There is two shorter (1.53 Å) and two longer (1.57 Å) P–O bond length. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 30–46°. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 29–43°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two LiO6 octahedra and corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 29–43°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. There are forty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one P5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+, one V3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+, one V3+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the seventeenth O2- site, O2- is bonded to three Li1+, one V3+, and one Si4+ atom to form distorted corner-sharing OLi3VSi trigonal bipyramids. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one Si4+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+, one V3+, and one Si4+ atom. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one Si4+ atom. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the twenty-fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the twenty-sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V3+, and one P5+ atom. In the twenty-seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Li1+, one V3+, and one P5+ atom. In the twenty-eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+, one V3+, and one P5+ atom. In the twenty-ninth O2- site, O2- is bonded in a 3-coordinate geometry

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K4Na4VMo7O20 by Materials Project

K4Na4VMo7O20 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 1.67–2.52 Å. In the second K1+ site, K1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 1.67–2.48 Å. In the third K1+ site, K1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 1.69–2.52 Å. In the fourth K1+ site, K1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 1.65–2.50 Å. In the fifth K1+ site, K1+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of K–O bond distances ranging from 1.57–3.17 Å. In the sixth K1+ site, K1+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of K–O bond distances ranging from 1.66–3.02 Å. In the seventh K1+ site, K1+ is bonded in a 2-coordinate geometry to four O2- atoms. There are a spread of K–O bond distances ranging from 1.62–3.07 Å. In the eighth K1+ site, K1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 1.65–2.76 Å. In the ninth K1+ site, K1+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of K–O bond distances ranging from 1.60–3.13 Å. In the tenth K1+ site, K1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are one shorter (1.95 Å) and two longer (2.50 Å) K–O bond lengths. In the eleventh K1+ site, K1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 1.91–2.55 Å. In the twelfth K1+ site, K1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 2.01–2.52 Å. In the thirteenth K1+ site, K1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 1.85–2.55 Å. In the fourteenth K1+ site, K1+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of K–O bond distances ranging from 2.01–3.25 Å. In the fifteenth K1+ site, K1+ is bonded in a 1-coordinate geometry to two O2- atoms. There are one shorter (1.93 Å) and one longer (2.37 Å) K–O bond lengths. In the sixteenth K1+ site, K1+ is bonded in a distorted single-bond geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 1.86–3.22 Å. There are sixteen inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.56–2.25 Å. In the second Na1+ site, Na1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.55–2.34 Å. In the third Na1+ site, Na1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.55–2.31 Å. In the fourth Na1+ site, Na1+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.54–2.48 Å. In the fifth Na1+ site, Na1+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.47–2.69 Å. In the sixth Na1+ site, Na1+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.54–2.53 Å. In the seventh Na1+ site, Na1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.49–2.67 Å. In the eighth Na1+ site, Na1+ is bonded in a 2-coordinate geometry to two O2- atoms. There is one shorter (1.83 Å) and one longer (2.16 Å) Na–O bond length. In the ninth Na1+ site, Na1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.81–2.92 Å. In the tenth Na1+ site, Na1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.73–2.89 Å. In the eleventh Na1+ site, Na1+ is bonded in a distorted single-bond geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.65–2.88 Å. In the twelfth Na1+ site, Na1+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 1.79–2.99 Å. In the thirteenth Na1+ site, Na1+ is bonded in a distorted single-bond geometry to two O2- atoms. There are one shorter (1.69 Å) and one longer (2.61 Å) Na–O bond lengths. In the fourteenth Na1+ site, Na1+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.79–2.84 Å. In the fifteenth Na1+ site, Na1+ is bonded in a distorted single-bond geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 1.71–3.03 Å. In the sixteenth Na1+ site, Na1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 1.83–2.88 Å. There are four inequivalent V2+ sites. In the first V2+ site, V2+ is bonded in a 2-coordinate geometry to five O2- atoms. There are a spread of V–O bond distances ranging from 1.90–2.81 Å. In the second V2+ site, V2+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of V–O bond distances ranging from 1.73–2.62 Å. In the third V2+ site, V2+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of V–O bond distances ranging from 1.77–1.93 Å. In the fourth V2+ site, V2+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of V–O bond distances ranging from 1.68–2.02 Å. There are twenty-eight inequivalent Mo+4.29+ sites. In the first Mo+4.29+ site, Mo+4.29+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 2.08–2.30 Å. In the second Mo+4.29+ site, Mo+4.29+ is bonded in a 4-coordinate geometry to four O2- atoms. There are two shorter (2.12 Å) and two longer (2.31 Å) Mo–O bond lengths. In the third Mo+4.29+ site, Mo+4.29+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 2.07–2.25 Å. In the fourth Mo+4.29+ site, Mo+4.29+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 2.08–2.30 Å. In the fifth Mo+4.29+ site, Mo+4.29+ is bonded in a distorted square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 2.09–2.22 Å. In the sixth Mo+4.29+ site, Mo+4.29+ is bonded in a 8-coordinate geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 2.10–2.40 Å. In the seventh Mo+4.29+ site, Mo+4.29+ is bonded in a distorted square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 2.06–2.24 Å. In the eighth Mo+4.29+ site, Mo+4.29+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 2.07–2.34 Å. In the ninth Mo+4.29+ site, Mo+4.29+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.86–2.07 Å. In the tenth Mo+4.29+ site, Mo+4.29+ is bonded in a distorted square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.81–2.08 Å. In the eleventh Mo+4.29+ site, Mo+4.29+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.85–2.07 Å. In the twelfth Mo+4.29+ site, Mo+4.29+ is bonded in a distorted square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.86–2.13 Å. In the thirteenth Mo+4.29+ site, Mo+4.29+ is bonded in a distorted square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.85–2.08 Å. In the fourteenth Mo+4.29+ site, Mo+4.29+ is bonded in a distorted square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.78–2.08 Å. In the fifteenth Mo+4.29+ site, Mo+4.29+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.92–2.06 Å. In the sixteenth Mo+4.29+ site, Mo+4.29+ is bonded in a distorted square co-planar geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.79–2.09 Å. In the seventeenth Mo+4.29+ site, Mo+4.29+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.85–2.44 Å. In the eighteenth Mo+4.29+ site, Mo+4.29+ is bonded in a distorted water-like geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.81–2.61 Å. In the nineteenth Mo+4.29+ site, Mo+4.29+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.85–2.57 Å. In the twentieth Mo+4.29+ site, Mo+4.29+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.82–2.49 Å. In the twenty-first Mo+4.29+ site, Mo+4.29+ is bonded in a distorted water-like geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.97–2.69 Å. In the twenty-second Mo+4.29+ site, Mo+4.29+ is bonded in a distorted water-like geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.90–2.68 Å. In the twenty-third Mo+4.29+ site, Mo+4.29+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.79–2.24 Å. In the twenty-fourth Mo+4.29+ site, Mo+4.29+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.93–2.05 Å. In the twenty-fifth Mo+4.29+ site, Mo+4.29+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.94–2.16 Å. In the twenty-sixth Mo+4.29+ site, Mo+4.29+ is bonded in a 2-coordinate geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.72–2.11 Å. In the twenty-seventh Mo+4.29+ site, Mo+4.29+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Mo–O bond distances ranging from 1.96–2.13 Å. In the twenty-eighth Mo+4.29+ site, Mo+4.29+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.63–2.43 Å. There are eighty inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, one Na1+, and two Mo+4.29+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two K1+ and two Mo+4.29+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Na1+ and two Mo+4.29+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one K1+, one Na1+, and two Mo+4.29+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, one Na1+, and two Mo+4.29+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, one Na1+, and two Mo+4.29+ atoms. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one K1+, one Na1+, and two Mo+4.29+ atoms. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two K1+ and two Mo+4.29+ atoms. In the ninth O2- site, O2- is bonded in a distorted linear geometry to two Mo+4.29+ atoms. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to two Mo+4.29+ and one O2- atom. The O–O bond length is 1.93 Å. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to two Mo+4.29+ atoms. In the twelfth O2- site, O2- is bonded in a 1-coordinate geome

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2Na4Li2Ti4Mn3Fe(SiO3)16 by Materials Project

K2Na4Li2Ti4Mn3Fe(SiO3)16 is Esseneite-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of K–O bond distances ranging from 2.80–3.23 Å. In the second K1+ site, K1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of K–O bond distances ranging from 2.81–3.24 Å. There are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–3.01 Å. In the second Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–3.02 Å. In the third Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–3.02 Å. In the fourth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–3.03 Å. There are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with four SiO4 tetrahedra, an edgeedge with one MnO6 octahedra, an edgeedge with one FeO6 octahedra, and edges with four TiO6 octahedra. There are a spread of Li–O bond distances ranging from 2.05–2.28 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with four SiO4 tetrahedra, edges with two MnO6 octahedra, and edges with four TiO6 octahedra. There are a spread of Li–O bond distances ranging from 2.06–2.27 Å. There are four inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share a cornercorner with one FeO6 octahedra, corners with five SiO4 tetrahedra, an edgeedge with one TiO6 octahedra, an edgeedge with one MnO6 octahedra, and edges with two LiO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Ti–O bond distances ranging from 1.73–2.27 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share a cornercorner with one MnO6 octahedra, corners with five SiO4 tetrahedra, an edgeedge with one TiO6 octahedra, an edgeedge with one MnO6 octahedra, and edges with two LiO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are a spread of Ti–O bond distances ranging from 1.73–2.25 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share a cornercorner with one MnO6 octahedra, corners with five SiO4 tetrahedra, an edgeedge with one TiO6 octahedra, an edgeedge with one MnO6 octahedra, and edges with two LiO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Ti–O bond distances ranging from 1.73–2.26 Å. In the fourth Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share a cornercorner with one MnO6 octahedra, corners with five SiO4 tetrahedra, an edgeedge with one TiO6 octahedra, an edgeedge with one FeO6 octahedra, and edges with two LiO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Ti–O bond distances ranging from 1.73–2.24 Å. There are three inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with five SiO4 tetrahedra, an edgeedge with one LiO6 octahedra, an edgeedge with one TiO6 octahedra, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are a spread of Mn–O bond distances ranging from 2.08–2.33 Å. In the second Mn2+ site, Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with five SiO4 tetrahedra, an edgeedge with one LiO6 octahedra, an edgeedge with one TiO6 octahedra, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Mn–O bond distances ranging from 2.08–2.32 Å. In the third Mn2+ site, Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with five SiO4 tetrahedra, an edgeedge with one LiO6 octahedra, an edgeedge with one TiO6 octahedra, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Mn–O bond distances ranging from 2.08–2.33 Å. Fe2+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with five SiO4 tetrahedra, an edgeedge with one LiO6 octahedra, an edgeedge with one TiO6 octahedra, and an edgeedge with one MnO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Fe–O bond distances ranging from 2.02–2.31 Å. There are sixteen inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra, a cornercorner with one MnO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–61°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra, a cornercorner with one MnO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–61°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra, a cornercorner with one FeO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–59°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra, a cornercorner with one MnO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–61°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MnO6 octahedra, a cornercorner with one FeO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–63°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two MnO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–63°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MnO6 octahedra, a cornercorner with one FeO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–63°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two MnO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–63°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the ninth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with three TiO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. In the tenth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with three TiO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–61°. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. In the eleventh Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with three TiO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. In the twelfth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with three TiO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. In the thirteenth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, a cornercorner with one TiO6 octahedra, a cornercorner with one MnO6 octahedra, a cornercorner with one FeO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–65°. There are a spread of Si–O bond distances ranging from 1.61–1.70 Å. In the fourteenth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, a cornercorner with one TiO6 octahedra, a cornercorner with one MnO6 octahedra, a cornercorner with one FeO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–65°. There are a spread of Si–O bond distances ranging from 1.60–1.70 Å. In the fifteenth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, a cornercorner with one TiO6 octahedra, corners with two MnO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–65°. There are a spread of Si–O bond distances ranging from 1.60–1.70 Å. In the sixteenth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one LiO6 octahedra, a cornercorner with one TiO6 octahedra, corners with two MnO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–64°. There are a spread of Si–O bond distances ranging from 1.60–1.70 Å. There are forty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ti4+, one Fe2+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ti4+, one Mn2+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ti4+, one Mn2+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ti4+, one Mn2+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe2+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Mn2+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Mn2+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geome

36 MATERIALS SCIENCE↗
DOE OSTI2021

Structural analysis of the PTEN:P-Rex2 signaling complex reveals how cancer-associated mutations coordinate to hyperactivate Rac1

The dual-specificity phosphatase PTEN functions as a tumor suppressor by hydrolyzing PI(3,4,5)P 3 to PI(4,5)P 2 to inhibit PI3K-AKT signaling and cellular proliferation. P-Rex2 is a guanine nucleotide exchange factor for Rho GTPases and can be activated by Gβγ subunits downstream of G protein–coupled receptor signaling and by PI(3,4,5)P 3 downstream of receptor tyrosine kinases. The PTEN:P-Rex2 complex is a commonly mutated signaling node in metastatic cancer. Assembly of the PTEN:P-Rex2 complex inhibits the activity of both proteins, and its dysregulation can drive PI3K-AKT signaling and cellular proliferation. Here, using cross-linking mass spectrometry and functional studies, we gained mechanistic insights into PTEN:P-Rex2 complex assembly and coinhibition. We found that PTEN was anchored to P-Rex2 by interactions between the PDZ-interacting motif in the PTEN C-terminal tail and the second PDZ domain of P-Rex2. This interaction bridged PTEN across the P-Rex2 surface, preventing PI(3,4,5)P 3 hydrolysis. Conversely, PTEN both allosterically promoted an autoinhibited conformation of P-Rex2 and blocked its binding to Gβγ. In addition, we observed that the PTEN-deactivating mutations and P-Rex2 truncations combined to drive Rac1 activation to a greater extent than did either single variant alone. These insights enabled us to propose a class of gain-of-function, cancer-associated mutations within the PTEN:P-Rex2 interface that uncouple PTEN from the inhibition of Rac1 signaling.

D’Andrea, Laura↗
DOE OSTI2025

Mixed-valence halide perovskites

Mixed-valence compounds—which feature an element in at least two different oxidation states—can display emergent optical and transport phenomena stemming from electron transfer between the different valences (intervalence charge-transfer; IVCT). As halide perovskites show promise as active materials in numerous optoelectronic devices, it is an opportune moment to incorporate and study the effects of mixed-valence in this versatile materials family, to access tunable electronic structures ranging from insulators to semiconductors to metals. Herein, we introduce the basic concepts of mixed-valence in molecules and discuss how these concepts may be extended to mixed-valence in extended solids. We then review the few studies of mixed valence in 3D and 2D halide perovskites and halide perovskites with mixed-valence impurities, ranging from studies in the early 1900s to the present day. In conclusion, through judicious choice of metal ion, its coordinating ligands and their geometry, and overall structural dimensionality, chemists can exert powerful synthetic control over electronic delocalization in mixed-valence perovskites, and we hope to see this intriguing materials class expand to encompass new compositions.

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

Artificial Iron Proteins: Modeling the Active Sites in Non-Heme Dioxygenases

An important class of non-heme dioxygenases contains a conserved Fe binding site that consists of a 2-His-1-carboxylate facial triad. Results from structural biology show that, in the resting state, these proteins are six-coordinate with aqua ligands occupying the remaining three coordination sites. Here, we have utilized biotin–streptavidin (Sav) technology to design new artificial Fe proteins (ArMs) that have many of the same structural features found within active sites of these non-heme dioxygenases. An Sav variant was isolated that contains the S 112 E mutation, which installed a carboxylate side chain in the appropriate position to bind to a synthetic Fe II complex confined within Sav. Structural studies using X-ray diffraction (XRD) methods revealed a facial triad binding site that is composed of two N donors from the biotinylated ligand and the monodentate coordination of the carboxylate from S 112 E. Two aqua ligands complete the primary coordination sphere of the Fe II center with both involved in hydrogen bond networks within Sav. The corresponding Fe III protein was also prepared and structurally characterized to show a six-coordinate complex with two exogenous acetato ligands. The Fe III protein was further shown to bind an exogenous azido ligand through replacement of one acetato ligand. Spectroscopic studies of the ArMs in solution support the results found by XRD.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Reining in Radium for Nuclear Medicine: Extra-Large Chelator Development for an Extra-Large Ion

Targeted α therapy (TAT) of soft-tissue cancers using the α particle-emitting radionuclide 223 Ra holds great potential because of its favorable nuclear properties, adequate availability, and established clinical use for treating metastatic prostate cancer of the bone. Despite these advantages, the use of 223 Ra has been largely overshadowed by other α emitters due to its challenging chelation chemistry. A key criterion that needs to be met for a radionuclide to be used in TAT is its stable attachment to a targeting vector via a bifunctional chelator. The low charge density of Ra 2+ arising from its large ionic radius weakens its electrostatic binding interactions with chelators, leading to insufficient complex stability in vivo. In this study, we synthesized and evaluated macropa-XL as a novel chelator for 223 Ra. It bears a large 21-crown-7 macrocyclic core and two picolinate pendent groups, which we hypothesized would effectively saturate the large coordination sphere of the Ra 2+ ion. The structural chemistry of macropa-XL was first established with the nonradioactive Ba 2+ ion using X-ray diffraction and X-ray absorption spectroscopy, which revealed the formation of an 11-coordinate complex in a rare anti pendent-arm configuration. Subsequently, the stability constant of the [Ra(macropa-XL)] complex was determined via competitive cation exchange with 223 Ra and 224 Ra radiotracers and compared with that of macropa, the current state-of-the-art chelator for Ra 2+ . A moderate log K ML value of 8.12 was measured for [Ra(macropa-XL)], which is approximately 1.5 log K units lower than the stability constant of [Ra(macropa)]. This relative decrease in Ra 2+ complex stability for macropa-XL versus macropa was further probed using density functional theory calculations. Additionally, macropa-XL was radiolabeled with 223 Ra, and the kinetic stability of the resulting complex was evaluated in human serum. Furthermore, although macropa-XL could effectively bind 223 Ra under mild conditions, the complex appeared to be unstable to transchelation. Collectively, this study sheds additional light on the chelation chemistry of the exotic Ra 2+ ion and contributes to the small, but growing, number of chelator development efforts for 223 Ra-based TAT.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Nanotubes from the Misfit Layered Compound (SmS) 1.19 TaS 2 : Atomic Structure, Charge Transfer, and Electrical Properties

Misfit layered compounds (MLCs) MX-TX 2 , where M, T = metal atoms and X = S, Se, or Te, and their nanotubes are of significant interest due to their rich chemistry and unique quasi-1D structure. In particular, LnX-TX 2 (Ln = rare-earth atom) constitute a relatively large family of MLCs, from which nanotubes have been synthesized. The properties of MLCs can be tuned by the chemical and structural interplay between LnX and TX 2 sublayers and alloying of each of the Ln, T, and X elements. In order to engineer them to gain desirable performance, a detailed understanding of their complex structure is indispensable. MLC nanotubes are a relative newcomer and offer new opportunities. In particular, like WS 2 nanotubes before, the confinement of the free carriers in these quasi-1D nanostructures and their chiral nature offer intriguing physical behavior. High-resolution transmission electron microscopy in conjunction with a focused ion beam are engaged to study SmS-TaS 2 nanotubes and their cross-sections at the atomic scale. The atomic resolution images distinctly reveal that Ta is in trigonal prismatic coordination with S atoms in a hexagonal structure. Furthermore, the position of the sulfur atoms in both the SmS and the TaS 2 sublattices is revealed. X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and X-ray absorption spectroscopy are carried out. These analyses conclude that charge transfer from the Sm to the Ta atoms leads to filling of the Ta 5d z 2 level, which is confirmed by density functional theory (DFT) calculations. Transport measurements show that the nanotubes are semimetallic with resistivities in the range of 10 –4 Ω·cm at room temperature, and magnetic susceptibility measurements show a superconducting transition at 4 K.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Electrochemical Oxidation in Garnet-Type Solid Electrolyte by Formation of Point Defects

All-solid-state batteries hold greater promise for improving safety and energy density over conventional battery technology employing organic liquid electrolytes. One of the required features of a Li + conducting solid electrolyte is electrochemical stability, attained thermodynamically or kinetically, within the targeted operating voltage and temperature ranges. Therefore, understanding of the oxidative or reductive degradation mechanism is important to allow the design of stable solid electrolyte materials. This work contributes to building an understanding of the oxidative degradation mechanism in lithium solid electrolytes at cell operating conditions. Here, we have focused on resolving the oxidative decomposition mechanism of Al-doped lithium garnet Li 6.28 Al 0.24 La 3 Zr 2 O 12 (LLZO) as a state-of-the-art inorganic ceramic electrolyte. By combining experimental and computational analyses, we show that oxidation of LLZO occurs by simultaneous loss of oxygen and lithium from the structure, resulting in substoichiometric LLZO, at a moderate temperature (80 °C) and a high electrode potential (4.3 V vs Li/Li + ). Based on X-ray absorption and diffraction analyses, we find that the zirconium coordination shells in LLZO contract while the crystal structure experiences positive chemical strain upon electrochemical oxidation. The results from ex situ structural characterization of both the local structure and crystal symmetry are supported by a substoichiometric LLZO with lithium and oxygen vacancies, modeled by density functional theory (DFT) calculations. These chemical and structural changes in LLZO suppress effective lithium-ion conductivity by an order of magnitude. Formation of lithium and oxygen vacancies in LLZO upon electrochemical oxidation is different from prior thermodynamic predictions of phase decomposition of LLZO. The difference here is that the experiments were conducted at near-room temperature, which can hinder the kinetics of phase separation, and thus, the resultant LLZO solid electrolyte is still single-phase but substoichiometric in Li and O. In conclusion, these findings contribute an important degradation mechanism of the electrolyte, relevant for practical operational conditions of solid-state batteries.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Template-free fabrication of fractal porous Y 2 O 3 monolithic foam and its functional modification by Ni-doping

Fractal structures which display nearly the same character at every scale exist widely in nature, however, it is still a great challenge to fabricate a fractal nanostructure. Herein, a Y 2 O 3 monolith with unique hierarchically fractal porous structure was fabricated via calcination of a fractal porous coordination polymer precursor. The monolith exhibits porous feature with the pore-size ranging from micrometers to nanometers. Interestingly, each level of the pore-wall is composed of secondary porous structures, whose pore-wall is composed of sub-level self-similar porous feature. Moreover, by Ni-doping in the coordination polymer precursor, fractal porous Ni@Y 2 O 3 was prepared, and exhibited enhanced activity in ethanol steam reforming compared with that of a common supported NiO catalyst.

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

Intra- and Intermolecular Self-Assembly of a 20-nm-Wide Supramolecular Hexagonal Grid.

For the past three decades, the coordination-driven self-assembly of three-dimensional structures has undergone rapid progress; however, parallel efforts to create large discrete two-dimensional architectures-as opposed to polymers-have met with limited success. The synthesis of metallo-supramolecular systems with well-defined shapes and sizes in the range of 10-100 nm remains challenging. Here we report the construction of a series of giant supramolecular hexagonal grids, with diameters on the order of 20 nm and molecular weights greater than 65 kDa, through a combination of intra- and intermolecular metal-mediated self-assembly steps. The hexagonal intermediates and the resulting self-assembled grid architectures were imaged at submolecular resolution by scanning tunnelling microscopy. Characterization (including by scanning tunnelling spectroscopy) enabled the unambiguous atomic-scale determination of fourteen hexagonal grid isomers.

Zhang, Zhe↗