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Materials Data on Y(CO3)2 by Materials Project

Y(CO3)2 crystallizes in the orthorhombic C222_1 space group. The structure is three-dimensional. there are two inequivalent Y sites. In the first Y site, Y is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Y–O bond distances ranging from 2.38–2.50 Å. In the second Y site, Y is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Y–O bond distances ranging from 2.37–2.46 Å. There are two inequivalent C sites. In the first C site, C is bonded in a distorted bent 120 degrees geometry to two O atoms. Both C–O bond lengths are 1.25 Å. In the second C site, C is bonded in a trigonal planar geometry to three O atoms. There is two shorter (1.29 Å) and one longer (1.30 Å) C–O bond length. There are seven inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to two Y and one C atom. In the second O site, O is bonded in a distorted T-shaped geometry to two Y and one C atom. In the third O site, O is bonded in a 1-coordinate geometry to two Y and one C atom. In the fourth O site, O is bonded in a single-bond geometry to one Y atom. In the fifth O site, O is bonded in a single-bond geometry to one Y atom. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Y and one C atom. In the seventh O site, O is bonded in a bent 120 degrees geometry to one Y and one C atom.

36 MATERIALS SCIENCE↗

Earth's partial pressure of CO2 over the past 120 Ma; evidence from Ce anomalies in the deep (greater than 600 m) Pacific Ocean, 1

It was found that Ce serves as a chemical tracer of paleo-oceanic redox conditions. It was shown that the unoxidized and soluble Ce(3+) in modern seawater exhibits a negative anomaly relative to the other soluble REE(3+). An expression of soluble Ce(3+) in seawater that was approximately 1900X greater than the average observed in Ce in 600-5000 m Pacific seawater was derived. Since Ce(CO3)(+) and Ce(CO3)2(-) complexes greatly exceed the Ce(PO4) complexes in seawater, the formulations of using carbonate complexes were followed and it was found that the calculated Ce and observed concentrations in the deep 600-5000 m Pacific Ocean agree within the uncertainties of the thermodynamic data. As expected, the calculated Ce concentrations are a strong function of pH and found to be lesser functions of CO3(2-) activities.

Liu, Y.-G↗

Materials Data on KY(CO3)2 by Materials Project

KY(CO3)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of K–O bond distances ranging from 2.80–3.24 Å. Y3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Y–O bond distances ranging from 2.30–2.50 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of C–O bond distances ranging from 1.28–1.32 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Y3+, and one C4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+, one Y3+, and one C4+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, two equivalent Y3+, and one C4+ atom.

36 MATERIALS SCIENCE↗

Materials Data on YH2(CO3)2 by Materials Project

YH2(CO3)2 crystallizes in the orthorhombic C222_1 space group. The structure is three-dimensional. there are two inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Y–O bond distances ranging from 2.36–2.48 Å. In the second Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Y–O bond distances ranging from 2.36–2.47 Å. There are two inequivalent C+3.50+ sites. In the first C+3.50+ site, C+3.50+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both C–O bond lengths are 1.27 Å. In the second C+3.50+ site, C+3.50+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.29 Å) and one longer (1.31 Å) C–O bond length. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two Y3+ and one C+3.50+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two Y3+ and one C+3.50+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Y3+ and one C+3.50+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Y3+ and one C+3.50+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two Y3+ and one C+3.50+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Y3+ and two equivalent H1+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Y3+ and two equivalent H1+ atoms.

36 MATERIALS SCIENCE↗

Engineering CoO x ‑Based Self-Supported Anodes for Pure-Water-Fed Anion-Exchange-Membrane Electrolysis

Commercial membrane electrolyzers rely on acidic fluorocarbon membranes and ionomers, requiring the use of expensive IrO x -based oxygen-evolution catalysts. Anion-exchange-membrane water electrolyzers (AEMWEs) operate in an alkaline environment, enabling the use of non-precious-metal catalysts. Here, we study and engineer CoO x -based catalyst-coated anodes deposited via hydrothermal synthesis directly onto porous transport layers both with and without thermal annealing. The self-supported, nanoneedle-structured Co3O4 anode, formed by annealing the as-synthesized cobalt carbonate hydroxide, Co­(CO3) x (OH) y , outperforms the baseline Co3O4 nanoparticle ink-based anode in pure-water-fed AEMWE due to the improved catalyst-layer continuity and thus number of electroactive Co species. The as-synthesized and unannealed Co­(CO3) x (OH) y , however, appears to undergo substantial conversion to a more-active CoO x (OH) y phase predominantly at the surface, with nominal Co3+ present and higher electrical conductivity, lowering the cell voltage to ∼200 mV at 1.0 A·cm–2 in pure-water-fed AEMWE compared to the conventional Co3O4 nanoparticle anodes. We analyze the differences in electrode electrochemical response between pure-water and KOH feed modes, finding distinct activation and degradation modes. The Co­(CO3) x (OH) y anode shows significant activation and slower degradation linked to the conversion to oxyhydroxide. We propose catalyst layer designs that promote both hydroxide and electron transport, alongside interfacial engineering strategies to obtain high performance while mitigating anode degradation.

anion-exchange-membrane water electrolysis↗

Materials Data on Ba6Y2Co4O15 by Materials Project

Ba6Y2Co4O15 crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. there are four inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.70–3.17 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.76–3.02 Å. In the third Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.79–3.15 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.60–3.20 Å. Y3+ is bonded to six O2- atoms to form YO6 octahedra that share corners with six CoO4 tetrahedra. There are a spread of Y–O bond distances ranging from 2.22–2.35 Å. There are two inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with four equivalent YO6 octahedra. The corner-sharing octahedra tilt angles range from 5–34°. There are a spread of Co–O bond distances ranging from 1.84–1.93 Å. In the second Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with two equivalent YO6 octahedra and a cornercorner with one CoO4 tetrahedra. The corner-sharing octahedra tilt angles range from 7–32°. There are a spread of Co–O bond distances ranging from 1.80–1.94 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to three Ba2+, one Y3+, and one Co3+ atom. In the second O2- site, O2- is bonded to four Ba2+, one Y3+, and one Co3+ atom to form distorted corner-sharing OBa4YCo octahedra. The corner-sharing octahedra tilt angles range from 54–63°. In the third O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+, one Y3+, and one Co3+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+, one Y3+, and one Co3+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Ba2+ and one Co3+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two equivalent Co3+ atoms. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to three Ba2+, one Y3+, and one Co3+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+, one Y3+, and one Co3+ atom.

36 MATERIALS SCIENCE↗

Effects of Short-Term Thermal Alteration on Organic Matter in Experimentally-Heated Tagish Lake Observed by Raman Spectroscopy

Carbonaceous chondrites exhibit a wide range of aqueous and thermal alteration characteristics. Examples of the thermally metamorphosed carbonaceous chondrites (TMCCs) include the C2-ung/CM2TIVs Belgica (B)-7904 and Yamato (Y) 86720. The alteration extent is the most complete in these meteorites and thus they are considered typical end-members of TMCCs exhibiting complete dehydration of matrix phyllosilicates [1, 2]. The estimated heating conditions are 10 to 10(sup 3) days at 700 C to 1 to 100 hours at 890 C, i.e. short-term heating induced by impact and/or solar radiation [3]. The chemical and bulk oxygen isotopic compositions of the matrix of the carbonate (CO3)-poor lithology of the Tagish Lake (hereafter Tag) meteorite bears similarities to these TMCCs [4]. We investigated the experimentally-heated Tag with the use of Raman spectroscopy to understand how short-term heating affects the maturity of insoluble organic matter (IOM) in aqueously altered meteorites.

Chan, Q. H. S.↗

Materials Data on Ba2Y2Co4O11 by Materials Project

Ba2Y2Co4O11 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with four equivalent BaO12 cuboctahedra, faces with four equivalent BaO12 cuboctahedra, faces with four equivalent CoO6 octahedra, and faces with four equivalent CoO5 square pyramids. There are a spread of Ba–O bond distances ranging from 2.75–3.07 Å. Y3+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Y–O bond distances ranging from 2.48–2.67 Å. There are two inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four equivalent CoO6 octahedra, corners with two equivalent CoO5 square pyramids, and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–11°. There are a spread of Co–O bond distances ranging from 1.88–2.15 Å. In the second Co3+ site, Co3+ is bonded to five O2- atoms to form CoO5 square pyramids that share corners with two equivalent CoO6 octahedra, corners with three equivalent CoO5 square pyramids, and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 20°. There are a spread of Co–O bond distances ranging from 1.86–2.00 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Ba2+ and two equivalent Co3+ atoms to form a mixture of distorted corner and edge-sharing OBa4Co2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, two equivalent Y3+, and two equivalent Co3+ atoms. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, two equivalent Y3+, and two equivalent Co3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, two equivalent Y3+, and two Co3+ atoms. In the fifth O2- site, O2- is bonded to four equivalent Ba2+ and two equivalent Co3+ atoms to form a mixture of distorted corner and edge-sharing OBa4Co2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the sixth O2- site, O2- is bonded in a distorted linear geometry to four equivalent Y3+ and two equivalent Co3+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on Na3YC2(O3F)2 by Materials Project

Na3Y(CO3)2F2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in an octahedral geometry to four O2- and two equivalent F1- atoms. There are two shorter (2.44 Å) and two longer (2.49 Å) Na–O bond lengths. Both Na–F bond lengths are 2.31 Å. In the second Na1+ site, Na1+ is bonded in a 7-coordinate geometry to five O2- and two F1- atoms. There are a spread of Na–O bond distances ranging from 2.38–2.96 Å. There are one shorter (2.37 Å) and one longer (2.44 Å) Na–F bond lengths. In the third Na1+ site, Na1+ is bonded in a 8-coordinate geometry to four O2- and two equivalent F1- atoms. There are two shorter (2.40 Å) and two longer (2.82 Å) Na–O bond lengths. Both Na–F bond lengths are 2.49 Å. In the fourth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to four O2- and two F1- atoms. There are a spread of Na–O bond distances ranging from 2.32–2.57 Å. There are one shorter (2.27 Å) and one longer (2.36 Å) Na–F bond lengths. Y3+ is bonded in a 8-coordinate geometry to six O2- and two F1- atoms. There are a spread of Y–O bond distances ranging from 2.39–2.62 Å. There are one shorter (2.18 Å) and one longer (2.20 Å) Y–F bond lengths. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of C–O bond distances ranging from 1.28–1.32 Å. In the second C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of C–O bond distances ranging from 1.27–1.32 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Y3+, and one C4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+, two equivalent Y3+, and one C4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one C4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Y3+, and one C4+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one C4+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+, two equivalent Y3+, and one C4+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to three Na1+ and one Y3+ atom to form distorted corner-sharing FNa3Y tetrahedra. In the second F1- site, F1- is bonded to three Na1+ and one Y3+ atom to form distorted corner-sharing FNa3Y tetrahedra.

36 MATERIALS SCIENCE↗

Mineralogy, Petrology, and Oxygen-isotope Compositions of Magnetite ± Fayalite Assemblages in CO3, CV3, and LL3 Chondrites

We report on the mineralogy, petrology, and O-isotope compositions of magnetite and fayalite (Fa90−100) from several metasomatically altered and weakly metamorphosed carbonaceous (Y-81020 [CO3.05], EET 90043 [CO3.1], MAC 88107 [CO3.1-like], and Kaba [oxidized Bali-like CV3.1]) and unequilibrated ordinary chondrites (UOCs; Semarkona [LL3.00], MET 00452 [LL3.05], MET 96503 [LL3.05], EET 910161 [LL3.05], Ngawi [LL3.0−3.6 breccia], and Vicencia [LL3.2]). In MAC 88107, EET 90043, and Kaba, nearly pure fayalite (Fa98−100) associates with phyllosilicates, magnetite, Fe, Ni-sulfides, and hedenbergite (Fs~50Wo~50), and occurs in all chondritic components—chondrules, matrices,and refractory inclusions. In UOCs, nearly pure fayalite (Fa95−98) associates withphyllosilicates and magnetite, and occurs mainly in matrices and fine-grained chondrulerims. Oxygen-isotope compositions of fayalite and magnetite in UOCs, COs, CVs, and MAC 88107 are in disequilibrium with those of chondrule olivine and low-Ca pyroxene phenocrysts, and plot along mass-dependent fractionation lines with slope of~0.5, butdifferent 17O (~+4.3 1.4‰,−0.2 0.6‰,−1.5 1‰, and−1.8 0.8‰, respectively). Based on the mineralogical observations, thermodynamic analysis, O-isotope compositions, and recently reported experimental data, we infer that (1) fayalite and magnetite in COs,CVs, MAC 88107, and UOCs resulted from aqueous fluid–rock interaction on the chondrite parent asteroids that occurred at low local water-to-rock mass ratios (0.1−0.4) and elevated temperatures (~100−300°C), and (2) 17O of fayalite and magnetite reflects O-isotope compositions of aqueous fluids on the host meteorite parent bodies. The observed differences in 17O of fayalite–magnetite assemblages in UOCs, CVs, COs, and MAC 88107suggest that water ices that accreted into the ordinary chondrite and carbonaceous chondrite parent asteroids had different 17O, implying spatial and/or temporal variations in O-isotope compositions of water in the protoplanetary disk.

Alexander N Krot↗

Intrinsically Conductive {pi}‑d Conjugated Layers with Co–N4 Active Sites for Efficient Nitrate Electrocatalysis and Zinc-Nitrate Batteries

Electrochemical synthesis of ammonia from nitrate has been extensively investigated as a potential alternative to the energy-intensive Haber-Bosch process. This approach not only operates under ambient conditions but also simultaneously removes nitrate contaminants while producing ammonia as a value-added product. However, the ongoing quest lies in designing an efficient electrocatalyst that achieves a high ammonia yield rate, high selectivity, and long-term stability. Herein, we report the outstanding performance of a Co–N4 coordinated π-d layered Co3(HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) in nitrate electrocatalysis. The unique combination of abundant Co–N4 active sites and superior electrical conductivity enables significant electrocatalytic activity, delivering a maximum ammonia yield rate of 56.8 mg cm–2 h–1 at −0.8 V vs RHE and a Faradaic efficiency of ∼91% at −0.4 V vs RHE. Mechanistic analysis reveals that alkaline conditions accelerate water dissociation to generate adsorbed hydrogen intermediates (H*), which are utilized by Co–N4 sites to drive the stepwise hydrogenation of nitrate to ammonia while suppressing competing hydrogen evolution reaction (HER) pathways. Furthermore, integration of this catalyst into a zinc-nitrate battery resulted in a maximum power density of 5.3 mW cm–2 and an open-circuit potential of ∼1.45 V. These results highlight the potential of π-d conjugated Co–N4 materials as an efficient catalyst for both environmental remediation and energy conversion.

Namvar, shahrirar↗