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Various impurities have been doped into ferroelectric BaTiO3-based materials, which are used in multi-layer ceramic capacitors, to improve their insulation resistance, reliability, and dielectric properties. However, the relationship between doped impurities and these device properties at the microscopic level remains unexplored. This study investigated the charge states and solubilities of doped impurities (V, Cr, Mn, Fe, Mg, Ca, and Sr) in BaTiO3 using density functional theory. We employed the screened hybrid functional and a rhombohedral lattice model. Owing to a better description of unoccupied states with the hybrid functional, equilibrium charge states and magnetic moments of V, Mn, and Fe impurities were in good agreement with those measured by magnetic susceptibility measurements. Furthermore, impurity levels of transition metal elements were qualitatively consistent with the experimental reports obtained by electron paramagnetic resonance. However, levels of Fe calculated in cubic BaTiO3 did not reproduce those observations. Therefore, a dynamically stable rhombohedral lattice was found to be more suitable than a cubic lattice for calculating the defects in BaTiO3. The solubility of transition metal dopants was highly dependent on the oxygen chemical potential conditions. By analyzing the cohesive energy, we observed a lower (higher) equilibrium charge state of the defect compared with the higher (lower) oxidation number of stable competitive phase enhanced solubility under reducing (oxidizing) conditions. Our calculations revealed that vanadium and manganese dopants were soluble under reducing conditions owing to instabilities of their metal phases and act as effective acceptors in BaTiO3. [ABSTRACT FROM AUTHOR]

Various impurities have been doped into ferroelectric BaTiO3-based materials, which are used in multi-layer ceramic capacitors, to improve their insulation resistance, reliability, and dielectric properties. However, the relationship between doped impurities and these device properties at the microscopic level remains unexplored. This study investigated the charge states and solubilities of doped impurities (V, Cr, Mn, Fe, Mg, Ca, and Sr) in BaTiO3 using density functional theory. We employed the screened hybrid functional and a rhombohedral lattice model. Owing to a better description of unoccupied states with the hybrid functional, equilibrium charge states and magnetic moments of V, Mn, and Fe impurities were in good agreement with those measured by magnetic susceptibility measurements. Furthermore, impurity levels of transition metal elements were qualitatively consistent with the experimental reports obtained by electron paramagnetic resonance. However, levels of Fe calculated in cubic BaTiO3 did not reproduce those observations. Therefore, a dynamically stable rhombohedral lattice was found to be more suitable than a cubic lattice for calculating the defects in BaTiO3. The solubility of transition metal dopants was highly dependent on the oxygen chemical potential conditions. By analyzing the cohesive energy, we observed a lower (higher) equilibrium charge state of the defect compared with the higher (lower) oxidation number of stable competitive phase enhanced solubility under reducing (oxidizing) conditions. Our calculations revealed that vanadium and manganese dopants were soluble under reducing conditions owing to instabilities of their metal phases and act as effective acceptors in BaTiO3. [ABSTRACT FROM AUTHOR]

We perform detailed potential energy surface explorations of BeM(CO)3− (M = Co, Rh, Ir) and BeM(CO)3 (M = Ni, Pd, Pt) using both single-reference and multireference-based methods. The present results at the CASPT2(12,12)/def2-QZVPD//M06-D3/def2-TZVPPD level reveal that the global minimum of BeM(CO)3− (M = Co, Rh, Ir) and BePt(CO)3 is a C3v symmetric structure with an 1A1 electronic state, where Be is located in a terminal position bonded to M along the center axis. For other cases, the C3v symmetric structure is a low-lying local minimum. Although the present complexes are isoelectronic with the recently reported BFe(CO)3− complex having a B–Fe quadruple bond, radial orbital-energy slope (ROS) analysis reveals that the highest occupied molecular orbital (HOMO) in the title complexes is slightly antibonding in nature, which bars a quadruple bonding assignment. Similar weak antibonding nature of HOMO in the previously reported BeM(CO)4 (M = Ru, Os) complexes is also noted in ROS analysis. The bonding analysis through energy decomposition analysis in combination with the natural orbital for chemical valence shows that the bonding between Be and M(CO)3q (q = −1 for M = Co, Rh, Ir and q = 0 for M = Ni, Pd, Pt) can be best described as Be in the ground state (1S) interacting with M(CO)30/− via dative bonds. The Be(spσ) → M(CO)3q σ-donation and the complementary Be(spσ) ← M(CO)3q σ-back donation make the overall σ bond, which is accompanied by two weak Be(pπ) ← M(CO)3q π-bonds. These complexes represent triply bonded terminal beryllium in an unusual zero oxidation state. [ABSTRACT FROM AUTHOR]

Open-source APOST-3D software features a large number of wavefunction analysis tools developed over the past 20 years, aiming at connecting classical chemical concepts with the electronic structure of molecules. APOST-3D relies on the identification of the atom in the molecule (AIM), and several analysis tools are implemented in the most general way so that they can be used in combination with any chosen AIM. Several Hilbert-space and real-space (fuzzy atom) AIM definitions are implemented. In general, global quantities are decomposed into one- and two-center terms, which can also be further grouped into fragment contributions. Real-space AIM methods involve numerical integrations, which are particularly costly for energy decomposition schemes. The current version of APOST-3D features several strategies to minimize numerical error and improve task parallelization. In addition to conventional population analysis of the density and other scalar fields, APOST-3D implements different schemes for oxidation state assignment (effective oxidation state and oxidation states localized orbitals), molecular energy decomposition schemes, and local spin analysis. The APOST-3D platform offers a user-friendly interface and a comprehensive suite of state-of-the-art tools to bridge the gap between theory and experiment, representing a valuable resource for both seasoned computational chemists and researchers with a focus on experimental work. We provide an overview of the code structure and its capabilities, together with illustrative examples. [ABSTRACT FROM AUTHOR]

The redox condition, a key parameter of mineralization, is one of the most difficult parameters to constrain precisely. Here we employ electron probe and X-ray photoelectron spectroscopy (XPS) to analyse sulphur (S) in apatite grains from five granitoid plutons that are differentially related to gold mineralization in the world-class gold fields of Jiaodong, Xiaoqinling, and Wutai-Hengshan within the North China Craton (NCC) to constrain the redox condition of melt. The results show increasing order of the apatite S content and S6+/ΣS ratios in the Linglong (only spatially close the Jiaodong gold deposits), Sunzhuang (related with the Yixingzhai gold deposits), Huashan (weakly related with the Xiaoqinling gold deposits), Wenyu (closely related with the Xiaoqinling gold deposits) and Guojialing plutons (closely related with the world-class Jiaodong gold deposits), indicating that the oxidation state increased from the Linglong pluton to the Guojialing pluton. The S concentrations of Guojialing, Wenyu, Huashan and Sunzhuang plutons, are estimated using previous methods are, 120–208 ppm, 107–138 ppm, 72–77 ppm and 10–74 ppm, respectively. Combined with the regional differences in gold mineralization in the North China Craton, the gradual increase in mineralization scale is consistent with the trend of increasing oxidation state in the granitoid plutons from Wutai-Hengshan to Xiaoqinling to Jiaodong goldfields, thus also underpinning the contribution of Mesozoic granites to gold mineralization in the North China Craton through providing the thermal energy and medium for the activation and migration of ore-forming fluids. [ABSTRACT FROM AUTHOR]

An unusual example of a potassium capped terminal cobalt–oxido complex has been isolated and crystallographically characterized. The synthesis of [tBu,TolDHP]CoOK proceeds from a previously reported parent compound, [tBu,TolDHP]CoOH, via deprotonation with KOtBu. Structural and electronic characterization suggest a weakly coupled dimer in a distinct seesaw geometry with a Co(III) oxidation state and a non-innocent radical ligand. [ABSTRACT FROM AUTHOR]

This study employs density functional theory at the SMD/B3LYP-D3/6-311+G(2d,p),def2-TZVPP//SMD/B3LYP-D3/6-31G(d),SDD level of theory to explore the mechanistic details of O2 generation from tBuOOH, using H218O as the solvent, in the presence of the Mn(II) catalyst [Mn2(mcbpen)2(H2O)2]2+. Since this chemistry was reported to occur through the reaction of Mn(III)(μ-O)Mn(IV)–O˙ with water, we first revaluated this proposal and found that it occurs with an activation barrier greater than 36 kcal mol−1, ruling out the functioning of such a dimer as the active catalyst. Experimental evidence has shown that the oxidation of [Mn2(mcbpen)2(H2O)2]2+ by tBuOOH in H218O produces the Mn(IV) species [Mn(18O)(mcbpen)]+. Our investigations revealed a plausible mechanism for this observation in which [Mn (18O)(mcbpen)]+ acts as the active catalyst, generating the tert-butyl peroxyl radical (tBuOO˙) through its reaction with tBuOOH. In this proposed mechanism, the O–O bond is formed through the interaction of tBuOO˙ with another [Mn(18O)(mcbpen)]+, finally leading to the formation of the 16O＝18O product. Our findings underscore the pivotal role of [Mn(18O)(mcbpen)]+ in both generating the active species tBuOO˙ and consuming it to produce 16O＝18O. With activation barriers as low as about 9 kcal mol−1, these elementary steps highlight the feasibility of our proposed mechanism. Moreover, this mechanism elucidates why, experimentally, one of the oxygen atoms in the released O2 comes from water, while the other originates from tBuOOH. This research broadens our understanding of high oxidation state manganese chemistry, setting the stage for the development of more efficient Mn-based catalysts, aimed at improving processes in both renewable energy and synthetic chemistry. [ABSTRACT FROM AUTHOR]

Hydrothermal conversion of actinide oxalates has recently gained attention as an innovative fabrication route for nuclear fuels but has remained mainly limited to tetra- or tri-valent cations. We report herein the reductive conversion of mixtures of uranyl and oxalate ions into UO2+x oxides under mild hydrothermal conditions (T = 250 °C). A multi-parametric study first led to specifying the optimal conditions in terms of pH, oxalate/U ratio and duration to provide a quantitative precipitation of uranium in the hyper-stoichiometric dioxide form with pH = 0.8; R = noxalate/nU = 3, and t = 72 hours. Particularly, pH was evidenced as a key parameter, with 3 different compounds obtained over a range of only 0.4 units. The mechanism leading to the formation of UO2+x was then investigated thanks to an in situ XANES study. Analysis of the supernatant showed that U(VI) was quickly reduced into U(IV) thanks to the presence of oxalates and/or their decomposition products in solution, following first-order kinetics. Tetravalent uranium was then hydrolysed, leading to the precipitation of UO2+x as the only crystalline phase. This study thus demonstrates that the hydrothermal conversion of actinide oxalates into oxides is an extremely versatile tool that can be implemented in a large variety of chemical systems, particularly in terms of the oxidation state of the cations initially present in solution. [ABSTRACT FROM AUTHOR]

Nanomaterials based on manganese oxides (MnOx) show considerable potential for large-scale electrochemical energy storage devices, driving significant research to explore their capabilities. One intriguing approach to enhance their performance involves the incorporation of other metals within their structure. Thus, we analyzed hierarchically obtained Cobalt (Co)-doped MnOx nanowires with different Co content, examining their storage properties. Notably, the initial impact of Co was observed in the structural characteristics of MnOx-based nanowires. As the Co content increased, there was a noticeable decrease in the cross-sectional widths of these nanowires. Also, we observed by XRD analysis that Co could effectively substitute manganese (Mn) within the crystal lattice. By XPS, the impact of Co doping on the Mn(IV)/Mn(III) ratio was of particular significance, as this ratio exhibited a direct correlation with the Co content (more Co, higher Mn(IV)/Mn(III) ratio), emphasizing the pivotal role of Co in modulating the oxidation states within these materials. Electrochemical studies revealed a remarkable dual behavior in the nanowires, combining pseudocapacitance and battery-like energy storage characteristics. Notably, our investigation uncovered a distinctive storage performance trend resembling a volcano, with the optimal energy storage material achieved using 1.4 wt.% Co-doped MnOx–Co nanowires. Applying the optimum material for a hybrid supercapacitor application, the energy and power density values were calculated as 48.08 Wh kg−1 and 2339.02 W kg−1, respectively. Thus, we believe that our comprehensive exploration of Co-doped MnOx nanowires provides valuable insights into understanding these materials' optimization for energy storage applications. [ABSTRACT FROM AUTHOR]

• A MAE-IC-ICP-MS method was set up to determine Se species in rice plants. • The accumulated Se by rice plants in Se(VI)-added soil was higher than that in Se(IV)-added soil. • Arsenite and As(V) facilitated the conversion of Se(IV) into Se-Cys and Se-Me. • Arsenite and As(V) had higher antagonism on Se species in Se(VI)-added soil than that in Se(IV)-added soil. • Arsenite had higher inhibiting effect on the Se species than As(V) in Se(VI)-added soil. Selenium (Se) in paddy rice is one of the significant sources of human Se nutrition. However, the effect of arsenic (As) pollution in soil on the translocation of Se species in rice plants is unclear. In this research, a pot experiment was designed to examine the effect of the addition of 50 mg As/kg soil as arsenite or arsenate on the migration of Se species from soil to indica Minghui 63 and Luyoumingzhan. The results showed that the antagonism between inorganic As and Se was closely related to the rice cultivar and Se oxidation state in soil. Relative to the standalone selenate treatment, arsenite significantly (p < 0.05) decreased the accumulation of selenocystine, selenomethionine and selenate in the roots, stems, sheaths, leaves, brans and kernels of both cultivars by 21.4%-100.0%, 40.0%-100.0%, 41.0%-100%, 5.4%-96.3%, 11.3%-100.0% and 26.2%-39.7% respectively, except for selenocystine in the kernels of indica Minghui 63 and selenomethionine in the leaves of indica Minghui 63 and the stems of indica Luyoumingzhan. Arsenate also decreased (p < 0.05) the accumulation of selenocystine, selenomethionine and selenate in the roots, stems, brans and kernels of both cultivars by 34.9%-100.0%, 30.2%-100.0%, 11.3%-100.0% and 5.6%-39.6% respectively, except for selenate in the stems of indica Minghui 63. However, relative to the standalone selenite treatment, arsenite and arsenate decreased (p < 0.05) the accumulation of selenocystine, selenomethionine and selenite only in the roots of indica Minghui 63 by 45.5%-100.0%. Our results suggested that arsenite and arsenate had better antagonism toward Se species in selenate-added soil than that in selenite-added soil; moreover, arsenite had a higher inhibiting effect on the accumulation of Se species than arsenate. [Display omitted] [ABSTRACT FROM AUTHOR]

In a unified regenerative fuel cell (URFC) or reversible fuel cell, the oxygen bifunctional catalyst must switch reversibly between the oxygen reduction reaction (ORR), fuel cell mode, and the oxygen evolution reaction (OER), electrolyzer mode. However, it is often unclear what effect alternating between ORR and OER has on the electrochemical behavior and physiochemical properties of the catalyst. Herein, operando X‐ray absorption spectroscopy (XAS) is utilized to monitor the continuous and dynamic evolution of the Co, Mn, and Fe oxidation states of perovskite catalysts Ba0.5Sr0.5Co0.8Fe0.2O3‐δ (BSCF) and La0.4Sr0.6MnO3‐δ (LSM), while the potential is oscillated between reducing and oxidizing potentials with cyclic voltammetry. The results reveal the importance of investigating bifunctional catalysts by alternating between fuel cell and electrolyzer operation and highlight the limitations and challenges of bifunctional catalysts. It is shown that the requirements for ORR and OER performance are divergent and that the oxidative potentials of OER are detrimental to ORR activity. These findings are used to give guidelines for future bifunctional catalyst design. Additionally, it is demonstrated how sunlight can be used to reactivate the ORR activity of LSM after rigorous cycling. [ABSTRACT FROM AUTHOR]

Cd‐free high‐bandgap Cu2ZnSnS4 (CZTS) solar cells are expected to offer green and low‐cost solutions to single‐junction and tandem photovoltaic markets. Despite attracting considerable attention in past years, reported certified efficiency has yet to exceed the 10% threshold. Sn‐related defects, especially those originating from Sn2+ oxidation states, lead to severe recombination loss and limit device performance. Here, the formation of these detrimental defects is suppressed by creating a more benign chemical environment during sulfurization annealing. With dominant Sn4+ states in the source material and the precursor, the oxidation state of Sn remains primarily in its native Sn4+ state during annealing and in the final film. Engineering the Sn‐related defects leads to shallower tail states in bulk CZTS and fewer interfacial defects. As a result, both radiative and non‐radiative recombination losses are alleviated, contributing to a certified 10.7% efficiency of the Cd‐free high‐bandgap CZTS solar cell. This strategy may advance various kesterite materials and other technologies with multivalent constituents. [ABSTRACT FROM AUTHOR]

Single-atom (group 15 and group 16 anions) bridged dimetallic complexes of low oxidation state uranium provide a convenient route to implement multielectron transfer and promote magnetic communication in uranium chemistry, but remain extremely rare. Here we report the synthesis, redox and magnetic properties of N3−, O2−, and S2− bridged diuranium complexes supported by bulky aryloxide ligands. The U(IV)/U(IV) nitride [Cs(THF)8][(U(OAr)3)2(μ-N)], 1 could be prepared and characterized but could not be reduced. Reduction of the neutral U(IV)/U(IV) complexes [(U(OAr)3)2(μ-X)] A (X = O) and B (X = S) led to the isolation and characterization of the U(IV)/U(III) and U(III)/U(III) analogues. Complexes [(K(THF)4)2(U(OAr)2)2(μ-S)2], 5 and [K(2.2.2-cryptand)]2[(U(OAr)3)2(μ-S)], 6 are the first examples of U(III) sulphide bridged complexes. Computational studies and redox properties allow the reactivity of the dimetallic complexes to be related to their electronic structure. [ABSTRACT FROM AUTHOR]

The Au/TiO 2 model catalyst has been extensively studied across various applications, yet its utilization in electrochemical CO 2 and CO reduction (EC CO 2 R and COR) remains underexplored. In this study, we employed the Au/TiO 2 /Ti system, prepared via a two-step process: initially forming rutile TiO 2 on metallic Ti through laser-assisted methods, followed by sputtering Au onto the surface. The experimental conditions included varying concentrations of KHCO 3 and phosphate, applied potentials, Au overlayer thickness, and laser treatment parameters for the Ti-based catalysts. The major products detected were syngas (CO and H 2), which varied with experimental settings, along with liquid formate and other hydrocarbons. The study also examined the role of surface species like *CO and H* in facilitating C–C coupling, drawing parallels to traditional Fischer-Tropsch (F-T) synthesis. Spectroscopic analyses, including XPS and UPS, were utilized to investigate interfacial electronic structures, oxidation states, and overlayer stability post-electrochemical processing. This research contributes to a deeper understanding of EC CO 2 R and COR mechanisms on Au/Ti electrodes, providing valuable insights into optimizing electrode design and operational conditions for enhanced catalytic efficiency in syngas production and direct F-T chemistry. [Display omitted] • Au/TiO 2 /Ti system was prepared by laser-assisting TiO 2 formation on Ti, followed by sputtering Au. • A tunable H 2 /CO ratio was by varying electrolyte concentrations and applied potentials in electrochemical CO 2 reduction. • Fischer-Tropsch synthesis pathway was understood through the role of *CO and H* in facilitating C–C coupling. • XPS and UPS revealed the oxidation states, interfacial electronic structures, and stability of Au overlayer. [ABSTRACT FROM AUTHOR]

Attempts to create a novel Mg−Be bond by reaction of [(DIPePBDI*)MgNa]2 with Be[N(SiMe3)2]2 failed; DIPePBDI*=HC[(tBu)C=N(DIPeP)]2, DIPeP=2,6‐Et2C‐phenyl. Even at elevated temperatures, no conversion was observed. This is likely caused by strong steric shielding of the Be center. A similar reaction with the more open Cp*BeCl gave in quantitative yield (DIPePBDI*)MgBeCp* (1). The crystal structure shows a Mg−Be bond of 2.469(4) Å. Homolytic cleavage of the Mg−Be bond requires ΔH=69.6 kcal mol−1 (cf. CpBe−BeCp 69.0 kcal mol−1 and (DIPPBDI)Mg−Mg(DIPPBDI) 55.8 kcal mol−1). Natural‐Population‐Analysis (NPA) shows fragment charges: (DIPePBDI*)Mg +0.27/BeCp* −0.27. The very low NPA charge on Be (+0.62) compared to Mg (+1.21) and the strongly upfield 9Be NMR signal at −23.7 ppm are in line with considerable electron density on Be and the formal oxidation state assignment of MgII−Be0. Despite this Mgδ+−Beδ− polarity, 1 is extremely thermally stable and unreactive towards H2, CO, N2, cyclohexene and carbodiimide. It reacted with benzophenone, azobenzene, phenyl acetylene, CO2 and CS2. Reaction with 1‐adamantyl azide led to reductive coupling and formation of an N6‐chain. The azide reagent also inserted in the Cp*−Be bond. The inertness of 1 is likely due to bulky ligands protecting the Mg−Be unit. [ABSTRACT FROM AUTHOR]

We have established a correlation between photocatalytic activity and dynamic structure/bond evolutions of BiOIO3‐based photocatalysts during CO2 reduction by combining operando X‐ray diffraction with photoelectron spectroscopy. More specifically, the selective photo‐deposition of PtOx species on BiOIO3 (010) facets could effectively promote the electron enrichment on Bi active sites of (100) facets for facilitating the adsorption/activation of CO2 molecules, leading to the formation of Bi sites with high oxidation state and the shrink of crystalline structures. With introducing light irradiation to drive CO2 reduction, the Bi active sites with high oxidation states transformed into normal Bi3+ state, accompanying with the expansion of crystalline structures. Owing to the dynamic structure, bond, and chemical‐state evolutions, a significant improvement of photocatalytic activity for CO evolution has been achieved on PtOx‐BiOIO3 (195.0 μmol g−1 ⋅ h−1), much higher than the pristine (61.9 μmol g−1 ⋅ h−1) as well as metal‐Pt decorated BiOIO3 (70.3 μmol g−1 ⋅ h−1) samples. This work provides new insights to correlate the intrinsically dynamic structure/bond evolutions with CO2 reduction activity, which may help to guide future photocatalyst design. [ABSTRACT FROM AUTHOR]

The oxidation state of the metal center is important for a conjugated metallacycle. Although high valent d0-metallacycles of main groups and early transition metals have been reported, such examples of late transition metals are limited. The reactions of ReOCl3(PPh3)2 with 2-ethynyl anilines produced alkenyl amino Re(V) complexes, which can be further oxidized to Re(VII) aza-metallacycles. The conjugated rhenacycle is nonaromatic, however, with close to zero NICS values and localized currents observed by AICD and GIMIC studies. [ABSTRACT FROM AUTHOR]

A new series of [CoIII–CF3]n+ complexes supported by a bidentate redox-active ligand is presented. The cationic [Co–CF3]+ complex was first obtained by reacting [CpCo(tBuUreaopda)] (Cp = cyclopentadienyl, opda = o-phenylenediamide) with an electrophilic trifluoromethyl source, for which the redox-active phenylenediamide ligand serves as a 2e− reservoir to generate [CpCp(tBuUreabqdi)(CF3)]+ (bqdi = benzoquinonediimine). Electrochemical studies of [Co–CF3]+ revealed two reversible 1e− reductions. Chemical reduction with 1 or 2 equiv. reducing agent enabled isolation of the neutral and anionic complexes, respectively, where the [CoIII–CF3] bond remains intact in all three oxidation states (n = +1, 0, −1). Structural analysis shows systematic changes to the redox-active ligand backbone upon reduction, consistent with sequential ligand-centered electron transfer in the series [bqdi]0 to [s-bqdi]˙− to [opda]2−. In contrast, the reaction of [CpCo(tBuUreaopda)] with alkyl triflates resulted in ligand-centered alkylation at the ureayl groups instead of the targeted Co–alkyl bond formation, suggesting less favorable bond formation at cobalt and greater nucleophilic accessibility of the ligand compared to the metal center. [ABSTRACT FROM AUTHOR]

This review focuses on the green synthesis methods, challenges, and applications of manganese oxide (Mn3O4) nanoparticles investigated in the past five years. Mn3O4 nanoparticles offer some unique properties that are attributed in part to the presence of mixed oxidation states of manganese (i.e. +2 and +3) in the particle, which can be utilized in a wide range of redox-sensitive applications, such as in developing supercapacitive energy storage materials. In addition, the green synthesis of Mn3O4 nanoparticles through plant extracts has potential uses in sustainable nanotechnology. Various plant extract-mediated synthesis techniques for Mn3O4 nanoparticles have been investigated and presented. By comparing the size and structure of the synthesized Mn3O4 nanoparticles, we have observed a consistent pattern of obtaining spherical particles with a size ranging from 16 to 50 nm. The morphology of the generated Mn3O4 nanoparticles can be influenced by the annealing temperature and the composition of the plant extract used during the nanoparticle synthesis. Additionally, numerous applications for the greenly produced Mn3O4 nanoparticles have been demonstrated. Mn3O4 nanoparticles derived from plant extracts have been found to possess antimicrobial properties, supercapacitive and electrochemical capabilities, and excellent pollutant degradation efficiency. However, the magnetic properties of these nanoparticles synthesized by plant extracts are yet to be explored for potential biomedical applications. Finally, challenges to existing synthetic methods and future perspectives on the potential applications of these green synthesized Mn3O4 nanoparticles are highlighted. [ABSTRACT FROM AUTHOR]

Free interconversion of cytochrome C (CytC) between native ferrous (Cyt‐FeII) and oxidized ferric (CytC‐FeIII) states is necessary to maintain the respiratory function of mitochondria. Disturbances in CytC‐FeIII to total CytC ratio may indicate mitochondrial dysfunction and apoptosis. Thus, tracking CytC oxidation state delivers important information about cellular physiology. In this work, we propose a novel methodology based on resonance Raman (rR) imaging optimized uniquely to track and qualitatively analyze the transition of Cyt‐FeII to CytC‐FeIII within live cells without affecting their morphology. None of the commonly used excitation lines allows such clear‐cut differentiation, contrary to the 405 nm applied in this work. The presented methodology provides a novel pathway in the label‐free detection of ferrous and ferric heme proteins. [ABSTRACT FROM AUTHOR]

Abstract: It is worth but still challenging to develop the low‐valent main group compounds with persistent room temperature phosphorescence (pRTP). Herein, we presented germylene‐based persistent phosphors by introduction of low‐valent Ge center into chromophore. A novel phosphors CzGe and its series of derivatives, namely CzGeS, CzGeSe, CzGeAu, and CzGeCu, were synthesized. Experiments and theoretical calculations reveal that the pRTP behavior were "turn on" due to the heavy atom effect of germylene. More importantly, the low‐valent of oxidation state and structural traits propelled GeCz had a balance between the intersystem crossing and the shortening of lifetime caused by the heavy atoms, resulting the ultralong lifetime of 309 ms and phosphorescent quantum efficiency of 15.84 %, which is remarkable among heavy main group phosphors. This research provides valuable insights to the design of heavy atoms in phosphors and expand the applications of germylene chemistry. [ABSTRACT FROM AUTHOR]

The use of ceria as catalyst in hydrogenation reactions is a recent trend, as they were uncovered to be active on a number of substrates, including alkynes, alkenes, and enones. While some studies focused on the use of well‐defined shapes, others emphasized the interest of defective structures. Overall, the meeting point of these studies is the need to characterize the surface reactivity vs. H2, by considering a number of interesting textures (films, nanopowders with various grain size or porosity), using monitoring techniques that preserve the original features of the materials. A key question is in particular to assess the possibility to form surface hydride through homolytic H2 splitting at cerium sites rather than at the oxygen one, a route recently highlighted as plausible. To address this question on small crystallites of CeO2, we designed a low‐temperature synthetic route for nanorods with an average grain size of 10 nm. Then, we employed near‐ambient‐pressure X‐ray photoelectron spectroscopy as an operando tool to monitor the cerium surface oxidation state during the initial annealing of the nanopowders, followed by exposure to a moderate pressure of H2 (0.52 mbar). We demonstrate that H2 homolytic splitting at cerium sites is the main activation process on this surface at 100 °C, leading to the oxidation of ca. 30 % of the surface cerium atoms from Ce3+ to Ce4+. The surface hydride species were however not stable at 250 °C, H2 was released, and cerium reduced back to Ce3+. A similar mechanism was observed on a defective ceria material obtained by calcination of CeO(OH)2, with comparable intensities. Overall, we report here CeO2 nanorods, exposing predominantly {100} and {110} facets, as showing an interesting surface reactivity for potential application in hydrogenation reactions, and we expose a straight operando methodology to delineate suitable temperatures to be used. [ABSTRACT FROM AUTHOR]

Primitive arc magmas are more oxidized and enriched in sulfur-34(34S) compared to mid-ocean ridge basalts. These findings have been linked to the addition of slab-derived volatiles, particularly sulfate, to arc magmas. However, the oxidation state of sulfur in slab fluids and the mechanisms of sulfur transfer in the slab remain inconclusive. Juxtaposed serpentinite and eclogitic metagabbro from the Voltri Massif (Italy) provide evidence for sulfur mobilization and associated redox processes during infiltration of fluids. Using bulk rock and in situ δ34S measurements, combined with thermodynamic calculations, we document the transfer of bisulfide-dominated, 34S-enriched fluids in equilibrium with serpentinite into adjacent metagabbro. We argue that the process documented in this study is pervasive along the subduction interface and infer that subsequent melting of these reacted slab-mantle interface rocks could produce melts that display the characteristic oxygen fugacity and sulfur isotope signatures of arc magmas worldwide. [ABSTRACT FROM AUTHOR]

Technetium-99 (99Tc) is found in aqueous environmental systems (due to nuclear testing, reprocessing, and accidents), where it can coexist with halides. While Tc(VII) is the primary oxidation state under oxic conditions, Tc(IV) can also be present in the environment. Accurate knowledge of the complexation of Tc(IV) species with Cl– improves understanding of Tc behavior in the environment. Results of batch solvent extraction experiments indicate that a single chloride complex is formed in solution from an exothermic reaction with a negative entropy. Computational results support classifying an outer-sphere complex between the Tc(IV) species and chloride. [ABSTRACT FROM AUTHOR]

Reasonable design is of great significance for improving the performance of electrochemiluminescence (ECL) co‐reactant accelerators. The different d‐band structure of metal single atoms will produce different oxidation states, which may change the adsorption of reaction intermediates to the catalyst and affect its catalytic activity. In this study, we have demonstrated that the ECL performances of graphite carbon nitride (CN) can be promoted by modulating the metal oxidation states of co‐reaction accelerator for the first time. The oxidation states of Au were modulated by the different electronic metal–support interaction (EMSI) between the co‐reaction accelerator (Au single atoms, Au nanoparticles [Au NPs]) and CN, and the effects of Au oxidation states on the ECL performances of CN were investigated. Comparison to pristine CN and CN nanosheets supported Au nanoparticles (Au NPs/CN), stronger and more stable ECL intensity of CN nanosheets supported Au single‐atoms (AuS/CN) was obtained. The ECL signal of AuS/CN was about 32.2 times that of the original CN, and 2.8 times that of Au NPs/CN in the same Au loading content (0.8%). Detailed mechanism revealed that AuS/CN with higher Au oxidation state has better conductivity and stronger catalytic activity, which promotes the electric reduction of CN and S2O82−, increases the lifetime of the excited state CN*, and significantly improves the ECL performance of CN. In addition, this work provides a detailed understanding of the essence of EMSI for the ECL intensity amplification and established a feasible method for the improvement of ECL capacities of co‐reactant accelerators. [ABSTRACT FROM AUTHOR]

The synchrotron technique of micro X-ray absorption near-edge structure spectroscopy at the sulfur K-edge (S-XANES) provides a unique opportunity to measure the proportion of different oxidation states of sulfur (S) in silicate glasses. Although applied extensively in the analysis of basaltic silicate glasses, few S-XANES studies have investigated variations in S oxidation states with fO2 in felsic silicate glasses. In addition, no study has systematically compared the S-XANES results obtained from the same samples at different photon flux densities to quantify the relationship between exposure time and changes in S speciation in silicate glass, as has been done for Fe and V. This study evaluates observed differences in S speciation measured in experimentally produced H2O-saturated dacitic glasses over a range of reducing to oxidizing conditions (from log fO2 = ΔFMQ-0.7 to ΔFMQ+3.3; FMQ is the fayalite-magnetite-quartz mineral redox buffer) and equilibrated at 1000 °C and 300 MPa. S-XANES spectra were collected at three different photon flux densities using three microspectroscopy beamlines. As is observed in S-XANES analyses of basaltic silicate glasses, beam-induced changes to the S6+/ΣS are observed as a function of photon flux density and beam exposure time. Our results demonstrate that silicate glasses of dacitic composition undergo beam-induced photo-reduction in samples equilibrated at ΔFMQ > +1.75 and photo-oxidation if equilibrated at ΔFMQ < +1. The time required to observe beam-induced changes in the spectra varies as a function of flux density, and our study establishes an upper photon density limit at ~1.0 × 1012 photons/μm2. The S6+/ΣS calculated from spectra collected below this absorbed photon limit at intermediate flux densities (~1–4 × 109 photons/s per μm2) are affected by beam damage, as no conditions were found to be completely free of beam-induced changes. However, the S6+/ΣS ratios calculated below the limit at intermediate flux densities are consistent with thermodynamic constraints, demonstrating that S6+/ΣS ratios calculated from S-XANES spectra can be considered reliable for estimating the oxygen fugacity. Our results carry important implications for the S budget of felsic magmas and dissolution mechanisms in evolved melts. While our results from all three flux densities show the presence of S4+ dissolved in relatively oxidized (ΔFMQ > +1.75) dacitic glass, even in the spectra exposed to the lowest photon densities, we are unable to rule out the possibility that the S4+ signal is the result of instantaneous X-ray irradiation induced beam damage using S-XANES alone. When our spectra are compared to S-XANES spectra from basaltic silicate glasses, important differences exist in the solubility of S2− and S6+ between dacitic silicate melts, pointing to differences in solubility mechanisms as melt composition changes. This study highlights the need for further investigation into beam damage systematics, presence of S4+, and the solubility mechanisms of different oxidation states of S as silicate melt composition changes. [ABSTRACT FROM AUTHOR]

Reaction of lithium 1,3‐diamidopropane Li2(TripNCN) (TripNCN=[{(Trip)NCH2}2CH2]2−, Trip=2,4,6‐triisopropylphenyl) with BeBr2(OEt2)2 gave the diamido beryllium complex, [(TripNCN)Be(OEt2)]. Deprotonation reactions between the bulkier 1,3‐diaminopropane (TCHPNCN)H2 (TCHPNCN=[{(TCHP)NCH2}2CH2]2−, TCHP=2,4,6‐tricyclohexylphenyl) and magnesium alkyls afforded the adduct complexes [(TCHPNCN)Mg(OEt2)] and [(TCHPNCN)Mg(THF)2], depending on the reaction conditions employed. Treating [(TCHPNCN)Mg(THF)2] with the N‐heterocyclic carbene :C{(MeNCMe)2} (TMC) gave [(TCHPNCN)Mg(TMC)2] via substitution of the THF ligands. Reactions of (ArNCN)H2 (Ar=Trip or TCHP) with Mg{CH2(SiMe3)}2, in the absence of Lewis bases, yielded the N‐bridged dimers [{(ArNCN)Mg}2]. Salt metathesis reactions between alkali metal salts M2(TCHPNCN) (M=Li or K) and CaI2 or SrI2 led to the THF adduct compounds [(TCHPNCN)Ca(THF)3] and [(TCHPNCN)Sr(THF)4], the differing number of THF ligands in which is a result of the different sizes of the metals involved. The described complexes hold potential as precursors to kinetically protected, low oxidation state group 2 metal species. [ABSTRACT FROM AUTHOR]

Redox condition is key to understanding crust formation and differentiation processes. We measured Eu anomalies in zircon in the Neoarchean tonalite-trondhjemite-granodiorite rocks (TTG) from the North China Craton to infer the Eu systematics in TTG melts, which allows us to constrain the minimum melt oxidation states. We find that those TTG samples formed at medium to high pressures have less Eu depletions (high Eu/Eu*) that are comparable to those of Phanerozoic porphyry copper deposits. To generate the zircon Eu signatures in the medium to high pressure TTGs, the melt oxygen fugacity needed to be at least 0–1 log units above the Ni-NiO buffer based on our crystallization modeling. The more oxidized compositions of medium to high pressure TTGs than those of low pressure TTGs are best explained as a consequence of endogenic oxidation due to garnet retention in their sources. Our findings further support that the redox condition of felsic crustal magmas is connected to differentiation pressure or crustal thickness, and this connection holds over much of the Earth's crustal differentiation history. In the late Archean, continuous formation of such oxidized crust may have profoundly influenced volatile output from Earth's interior and oxidative weathering processes at the surface. [ABSTRACT FROM AUTHOR]

This study introduces a novel mathematical approach rooted in X-ray spectroscopy principles to evaluate the oxidation state of sulfur, which is then applied in concrete and cementitious materials. Unlike previous studies that relied on an empirical quadratic relationship based on the ratios of characteristic X-ray lines (SKα, SKβ, and SKβ') for sulfur oxidation state determination, unique linear relationships between the intensities of the three X-ray lines for each oxidation state and total sulfur were utilized. Rational equations are then derived by combining these linear relationships for each species. Two independent rational calibration curves are constructed using the SKβ/SKα and SKβ'/SKβ ratios for samples containing sulfide-sulfate mixtures, irrespective of total sulfur concentration within the range of 0.3% to 2.0% by weight of concrete. These equations demonstrated interchangeability across three simulated matrices (Portland cement, concrete, and silica) and two sulfide species (pyrrhotite and pyrite). Absolute quantification of sulfide and sulfate species in concrete is achieved by independently measuring total sulfur. Compared to previous quadratic and linear equations, this approach is shown to minimize the difference between the experimental and calculated ratios of the calibration samples. Agreement was also observed between the sulfate ratio calculated through the rational approach and gravimetric analysis for concrete samples. [ABSTRACT FROM AUTHOR]

The manuscript reports the synthesis of Dy3+ incorporated lithium magnesium borate glass by melt quenching technique. FTIR study revealed the presence of both BO3 as well as tetrahedral BO4 units through their characteristic frequencies. Photoluminescence (PL) study of unirradiated samples confirmed the presence of Dy dopant in the '+3' oxidation states from the characteristic emissions at 482, 578, 666 and 716 nm corresponding to 4F9/2 → 6H15/2, 4F9/2 → 6H13/2 and 4F9/2 → 6H11/2, 4F9/2 → 6H9/2 transitions, respectively. Thermal neutron and gamma irradiated PL emission and lifetime characteristics were discussed in details based on the different defect centers. Thermal neutron irradiated TL study showed that the material has a broad and single dosimetry glow peak at about 450 K which showed high fading due to low temperature peak. TL based neutron sensitivity of LMB: Dy3+ was found to be about 37.4 times less than that of standard TLD-100 (LiF: Mg, Ti) powder. The net TL response from about 3 to 83 mSv of neutron dose was found to be linear (Adj. R2 = 0.9994) which is one of the most desirable properties for dosimetry applications. In addition, the TL trap parameters were evaluated using both deconvolution of TL glow curve and peak shape method as suggested by Chen which were found to be matching with each other. [ABSTRACT FROM AUTHOR]

Numerous strategies for enhancing the reactivity and properties of p-block elements have been devised in the past decades. This Account discusses our approaches by distinct ligand control on p-block elements in their normal (group) oxidation states. Catecholato ligands on silicon, germanium, or phosphorus produce a range of rewarding properties. Substantial electron withdrawal paired with structural constraint effects (influence of deformation energy) impart Lewis superacidity to these abundant elements. The ease of synthesis of such species facilitates screening in catalysis, promising a range of applications by powerful bond activation. Low-barrier Si–O/Si–O bond metathesis provides the most abundant bond in our Earth's crust, with adaptive features under mild conditions, and establishes a new branch of constitutional dynamic chemistry. The redox-active character of catecholates grants access to novel compounds with tunable open-shell features. Overall, p-block catecholates offer unique opportunities due to their versatile features that will enrich the chemistry of the main-group elements. 1 Introduction 2 Halogenated Catecholates at Silicon Cause Substantial Lewis Acidity 3 Constitutional Dynamics Cause a Structural Mystery 4 Strong Silicon Lewis Acids Allow the Exploration of Uncharted Structures, Bond Activations, and Catalysis 5 The Catechol Approach on Other Elements: Germanium and Phosphorus 6 Catechols Are Redox Active: Also at Silicon 7 Conclusion [ABSTRACT FROM AUTHOR]

This contribution investigates the effect of variable copper incorporation (x = 0.2, 1.0, 2.0, and 4.0) in silicate (45 SiO2, 24.5 CaO, 24.5 Na2O, 6P2O5wt%) and modified borate (45 B2O3, 24.5 CaO, 24.5 Na2O, 6P2O5wt%) bioglass materials to be used for bone bonding applications. X-ray absorption fine structure spectroscopy (XAFS) has been used to determine the oxidation states and local coordination structure of Cu atoms in silicate-based and borate-based glasses at the Cu K-edge (~ 8979 eV). The oxidation states of Cu atoms have been determined by near-edge XAFS (XANES) fingerprinting employing reference standard compounds of Cu. Cu (I) and Cu (II) XANES spectra of the standard reference compounds were linearly combined to fit the normalized μ(E) data of the collected XANES spectra using linear combination fitting (LCF approach). The obtained results prove that most of the silicate glass samples contain Cu2O almost exclusively, while modified borate glass samples contain a significant mixture of Cu2O and CuO phases. According to the literature, the remarkable coexistence of Cu2O and CuO phases within the borate sample, particularly when x = 4, promotes the conversion process to allow the more facile formation of hydroxy carbonate apatite (HCA). The best fit structural parameters derived from extended-XAFS (EXAFS) fitting show that the ratio between Cu (I) and Cu (II) in borate glass agreed well with that extracted from XANES analysis. XANES and EXAFS conclude that borate glass with x = 4 is the most suitable composition for bone bonding applications. [ABSTRACT FROM AUTHOR]

The intricate relationship between local atomic arrangements and electronic states significantly influences the electrochemical properties of Li‐ion battery cathode materials. Despite decades of investigation, a consensus regarding the local atomic and electronic structure of LiNiO2 remains elusive. This ambiguity stems from the potential distortion of Ni sites, either via Jahn‐Teller (JT) distortion or bond disproportionation (BD), complicating the understanding of the charge compensation mechanism involving Ni and O. This study compares the structures of LiNiO2 and NaNiO2, a JT system, using an innovative approach that integrates bulk spectroscopy techniques on standardized interoperable samples for enhanced reliability. While X‐r and theoretical calculations fail to differentiate between the proposed scenarios, Raman spectroscopy highlights local structural distinctions between monoclinic NaNiO2 and rhombohedral LiNiO2. HAXPES confirms various formal oxidation states for Ni, supported by RIXS data indicating 3d8 states, emphasizing negative charge transfer from Ni and some bond disproportionation in LiNiO2. Regarding charge compensation, XRS and RIXS suggest oxygen hole involvement in redox activity, whereas Raman spectroscopy does not detect molecular oxygen. This comprehensive spectroscopic analysis highlights the importance of correlative characterization workflows in elucidating complex structural‐electrochemical relationships. [ABSTRACT FROM AUTHOR]

NHC-based pincers (NHC = N-heterocyclic carbene) have been broadly employed as supporting platforms, and their palladium complexes have found many synthetic applications. However, previous studies mainly focused on the NHC pincers of palladium featuring an oxidation number of +II. In contrast, oxidation of these well-defined Pd(II) species and the study of their fundamental high-valent Pd chemistry remain largely undeveloped. In addition, from a perspective of PdII/PdIV catalysis, the reactivity and degradation of NHC pincers in catalytically relevant reactions have not been well understood. In this work, a series of Pd(II) complexes supported by a well-known NHC^Aryl^NHC pincer platform have been prepared. Their reactivity towards various oxidizing reagents, including halogen surrogates, electrophilic fluorine reagents, and alkyl/aryl halides, has been examined. In some cases, ambient-characterizable high-valent Pd NHCs, which have been scarcely reported, were obtained. The carbenes incorporated into the pincer framework proved to be effective spectator donors. In contrast, the central aryl moiety exhibits versatile reactivity and collapse pathways, allowing it to function either as a spectator or a non-innocent actor. [ABSTRACT FROM AUTHOR]

Silicon compounds containing silicon–silicon bond with a variety of unusual oxidation states are quite important, because their high reactivity leads to the formation of a variety of silicon compounds. The isolation of such compounds with unusual oxidation states requires a resilient synthetic strategy. Herein, we report the synthesis of a silicon based spirocyclic compound containing a hyper-valent silicon atom and a silicon–silicon bond. The computational calculations employing natural bond orbital (NBO) analysis and energy decomposition analysis–natural orbitals for chemical valence (EDA–NOCV) reveal that the nature of bonding between the silicon atoms is of an electron sharing nature. [ABSTRACT FROM AUTHOR]

To generate red emissions, manganese (IV) ions have recently gained recognition as potent non-rare-earth activators. However, the oxide and fluoride hosts that offer suitable environments for Mn4+ require careful preparation, involving precise control of reaction parameters like redox equilibrium and temperature. In the current work, we show simultaneous oxidation of Mn2+ to Mn4+ by devitrification of glassy Na 2 Ge 4 O 9 : Mn under moderate atmospheric conditions and under the argon atmosphere. The G-sample was devitrified via thermal treatment after the parent glass, which shares the same chemical formula as dilithium tetragermanate (Na 2 Ge 4 O 9), was created through the use of traditional melt-quenching (MQ). Optical spectroscopy and electron paramagnetic resonance (EPR) spectroscopic are utilized to confirm the Mn2+ oxidation to Mn4+ from glass stat to glass ceramic after thermal treatment. Due to the transition from Mn2+ to Mn4+, a sharp 668 nm emission peak is recorded whereas the red emission peaking at 611 nm monitored in glass is steadily reduced. The temperature-dependent PL spectra of the Na 2 Ge 4 O 9 :0.1Mn+4, red-emitting GC in the temperature range ∼295–490 K were recorded. The PL emission intensity decreases gradually with increasing the temperature. The technique showcased for producing Na 2 Ge 4 O 9 :Mn4+ phosphors could be expanded to synthesize other phosphors incorporating activators possessing a high oxidation state. [ABSTRACT FROM AUTHOR]

Obliteration of carbon monoxide is significant due to its hazardous effect on human health and potential application in different fields. Catalytic CO oxidation at lower temperature is the most convenient method to diminish the toxicity of CO. The low-cost catalysts which are exhibiting higher activity at lower temperature with good stability are in demand. The nanosized Rh-doped MnO2 catalysts have been prepared by dextrose-assisted co-precipitation method. Catalytic CO oxidation reaction was carried out over these prepared nanocatalysts under environmentally suitable conditions. XRD confirms the phase formation of prepared catalysts. These samples exhibit rod-like morphology with thickness of rods of less than 10 nm which is substantiated from electron microscopy images. XPS data reveals the oxidation state of Mn (+ 4) and Rh (+ 3). These catalysts are highly active for CO oxidation reaction at lower temperature, and one showed complete CO conversion at room temperature. The time-on-stream studies revealed that these catalysts are highly stable for CO oxidation for several hours. These catalysts are decidedly stable in moist condition and also showed higher activity in the presence of moisture, indicating participation of moisture in the oxidation reaction at above room temperatures. [ABSTRACT FROM AUTHOR]

Surface passivation, a desirable natural consequence during initial oxidation of alloys, is the foundation for functioning of corrosion and oxidation resistant alloys ranging from industrial stainless steel to kitchen utensils. This initial oxidation has been long perceived to vary with crystal facet, however, the underlying mechanism remains elusive. Here, using in situ environmental transmission electron microscopy, we gain atomic details on crystal facet dependent initial oxidation behavior in a model Ni-5Cr alloy. We find the (001) surface shows higher initial oxidation resistance as compared to the (111) surface. We reveal the crystal facet dependent oxidation is related to an interfacial atomic sieving effect, wherein the oxide/metal interface selectively promotes diffusion of certain atomic species. Density functional theory calculations rationalize the oxygen diffusion across Ni(111)/NiO(111) interface, as contrasted with Ni(001)/NiO(111), is enhanced. We unveil that crystal facet with initial fast oxidation rate could conversely switch to a slow steady state oxidation. Self-passivation in metallic alloys is a fundamental issue for corrosion and oxidation resistance. Here, authors demonstrate crystal facet-dependent initial oxidation behavior in a model Ni-Cr alloy, using in situ environmental TEM and DFT calculations. They show that the (001) facet exhibits incipient oxidation resistance compared to the (111) facet. [ABSTRACT FROM AUTHOR]

Pentavalent uranium compounds are key components of uranium's redox chemistry and play important roles in environmental transport. Despite this, well‐characterized U(V) compounds are scarce primarily because of their instability with respect to disproportionation to U(IV) and U(VI). In this work, we provide an alternate route to incorporation of U(V) into a crystalline lattice where different oxidation states of uranium can be stabilized through the incorporation of secondary cations with different sizes and charges. We show that iriginite‐based crystalline layers allow for systematically replacing U(VI) with U(V) through aliovalent substitution of 2+ alkaline‐earth or 3+ rare‐earth cations as dopant ions under high‐temperature conditions, specifically Ca(UVIO2)W4O14 and Ln(UVO2)W4O14 (Ln=Nd, Sm, Eu, Gd, Yb). Evidence for the existence of U(V) and U(VI) is supported by single‐crystal X‐ray diffraction, high energy resolution X‐ray absorption near edge structure, X‐ray photoelectron spectroscopy, and optical absorption spectroscopy. In contrast with other reported U(V) materials, the U(V) single crystals obtained using this route are relatively large (several centimeters) and easily reproducible, and thus provide a substantial improvement in the facile synthesis and stabilization of U(V). [ABSTRACT FROM AUTHOR]

Aquasols produced by exploding copper wires represent complex systems in which identifying individual colloidal components poses challenges due to broad and multimodal size distributions and varying shares among oxidation states. To evaluate the reproducibility of copper wire explosion, the size distribution of metallic and oxidized colloidal components within the 10–300 nm diameter range was assessed. Classification of each individual particle into bins according to size and chemical composition was accomplished by reconstructing the recorded optical extinction spectra of three sols produced under identical conditions as the weighted sum of the extinction spectra of individual copper and copper-oxide particles, computed using Mie theory. Our spectrophotometry-based component analysis revealed differences in particle number concentrations of the mainly oxidized nanoparticles, corresponding to deviations observed in the ultraviolet portion of the extinction spectra. Notable uniformity was observed, however, in the number of metallic fine particles, consistent with agreement in spectral features in the visible range. Regarding mass concentration, practically no differences were observed among the three samples, with nano-to-fine ratios of copper particles agreeing within 0.45%. Despite the complex processes during explosion leading to limited reproducibility in the ratio of different copper oxidation states, very good reproducibility (54.2 ± 0.7%) was found when comparing the total copper content of the samples to the mass of the exploded copper wire. [ABSTRACT FROM AUTHOR]

The effect of Ru-substitution (5–15 %) on the charge ordering of Y 0.5 Ca 0.5 MnO 3 has been investigated in this paper. Ru, existing in different oxidation states such as Ru4+ and Ru5+, plays an immense role in causing ferromagnetic (FM) superexchange interactions with Mn3+ ions. This, combined with the FM double-exchange interactions between Mn3+ and Mn4+ ions, destroys charge ordering. The development of ferromagnetism in Ru-substituted compounds is understood experimentally through the remarkable enhancement of dc magnetization with a simultaneous shift of T C from 57 K to 95 K with increasing Ru content from x = 0.05 to x = 0.15. The appearance of hysteresis for higher doping concentrations further confirms the FM nature. Concomitant with the favorable impact on the magnetic nature, there is also a development of magnetocaloric properties upon Ru-substitution. The maximum magnetic entropy change for x = 0.05 to 0.15 that was found to peak at T C ranges from 1.08 J/kg/K to 2.8 J/kg/K respectively for a field change of 9 T. The corresponding relative cooling power (RCP) increases from 76 J/kg to 324 J/kg indicating a significant growth of RCP with Ru substitution. These salient features of Ru-doped Y 0.5 Ca 0.5 MnO 3 would make it a suitable candidate for magnetic refrigeration. [ABSTRACT FROM AUTHOR]

The improvement of photovoltaic and stability performance of tin (Sn)‐based halide perovskite solar cells is impeded by notorious oxidation issues and Anderson localization. Despite previous implements in antioxidation through the incorporation of Lewis base additives, there still exist ongoing uncertainties surrounding its complex interaction mechanisms. A perplexing phenomenon regarding accelerated oxidation in acrylic acid is discovered that deviates from conventional Lewis base–acid reaction. The underlying insights into the deprotonation of acrylic acid followed by the formation of a "tripod" ionic bonding form are provided, which results in amplifying the delocalization effect of electrons of Sn2+. Furthermore, with the assistance of acrylamide and acrolein, synergistic enhancement in terms of the antioxidation and suppression of Anderson localization can be achieved — a concept referred to as "Dual Synergistic Engineering". This suppresses the oxidation of Sn2+ and reduces Sn4+ content by ≈76%. Meanwhile, the diffusion length is prolonged significantly from 195.9 to 458.9 nm. The optimized all‐inorganic Sn/Pb‐based perovskite solar cells exhibit a power conversion efficiency of above 14% with enhanced stability. These findings provide an alternative viewpoint for comprehending the impact of chemical interaction on oxidation and crystal growth in Sn/Pb‐based perovskites. [ABSTRACT FROM AUTHOR]

Magnetic materials can display many solutions to the electronic-structure problem, corresponding to different local or global minima of the energy functional. In Hartree-Fock or density-functional theory different single-determinant solutions lead to different magnetizations, ionic oxidation states, hybridizations, and inter-site magnetic couplings. The vast majority of these states can be fingerprinted through their projection on the atomic orbitals of the magnetic ions. We have devised an approach that provides an effective control over these occupation matrices, allowing us to systematically explore the landscape of the potential energy surface. We showcase the emergence of a complex zoology of self-consistent states; even more so when semi-local density-functional theory is augmented - and typically made more accurate - by Hubbard corrections. Such extensive explorations allow to robustly identify the ground state of magnetic systems, and to assess the accuracy (or not) of current functionals and approximations. [ABSTRACT FROM AUTHOR]

Molecular‐level insight into the interfacial composition of electrodes at the solid‐electrolyte and the solid‐electrode interface is essential to understanding the charge transfer processes, which are vital for electrochemical (EC) and photoelectrochemical (PEC) applications. However, spectroscopic access to both interfaces, particularly upon application of an external bias, remains a challenge. Here, in situ surface sensitive vibrational sum‐frequency generation (VSFG) spectroscopy is used for the first time to directly access the interfacial structure of a cobalt‐containing Prussian blue analog (Co‐PBA) in contact with the electrolyte and TiO2/Au surface. Structural and compositional changes of the Prussian blue layer during electrochemical oxidation are studied by monitoring the stretching vibration of the CN group. At open circuit potential, VSFG reveals a non‐homogeneous distribution of oxidation states of metal sites: FeIII–CN–CoII and FeII–CN–CoIII coordination motifs are dominantly observed at the Co‐PBA|TiO2 interface, while it is only the FeII–CN–CoII unit at the electrolyte interface. Upon increasing the potential applied to the electrode, the partial oxidation of FeII–CN–CoII to FeIII–CN–CoII is observed followed by its transformation to FeII–CN–CoIII via charge transfer and, finally, the formation of FeIII–CN–CoIII species at the interface with TiO2 and the electrolyte. [ABSTRACT FROM AUTHOR]

Synthetic multimetallic porphyrinoids are potential candidates in catalysis, molecular magnetism and as modern optoelectronic materials. Introducing electronic heterogenity in these multi‐porphyrinoids shall bring in novel electronic and redox characteristics. In this direction, herein we report four discrete Corrole‐Porphyrin‐Corrole C[10] ⋅ P[5,15] ⋅ C[10] hybrids that have both corrole and porphyrin units covalently connected together. Metal ions in diverse oxidation states have been incorporated into respective cores to achieve homo and heterotrinuclear metal complexes. Selective metalation at the porphyrin and corrole cores was achieved by step‐wise insertion of Zn(II)/Cu(II), Zn(II)/Ga(III) and Cu(II)/Cu(II) ions to suit the dianionic and trianionic pockets, respectively. Single crystal X‐ray diffraction studies reveal the solid‐state structural evidence for both homo‐, and hetero‐trinuclear metal complexes. The Zn(II) and Ga(III) moieties have two distinct geometries in the molecular assembly. The geometry of Zn(II) at the porphyrin core is a perfect square planar, whereas the Ga(III) geometry at the corrole is square pyramidal with pyridine as an axial ligand. In case of homotrinuclear Cu(II) complex, the Cu(II) ions adopt square planar geometry irrespective of the core. Similar to all porphyrin trimers, C[10] ⋅ P[5,15] ⋅ C[10] trimers exhibit significant excitonic coupling between corrole and porphyrin units in the absorption spectra. The cyclic voltametric investigations also reveal electronic coupling between the individual chromophores despite the non‐coplanar arrangement amongst the individual macrocycles. [ABSTRACT FROM AUTHOR]

Three new nitrides La3MN5 (M=Cr, Mn, and Mo) have been synthesized using a high pressure azide route. These are the first examples of ternary Cs3CoCl5‐type nitrides, and show that this (MN4)NLa3 antiperovskite structure type may be used to stabilise high oxidation‐state transition metals in tetrahedral molecular [MN4]n− nitridometallate anions. Magnetic measurements confirm that Cr and Mo are in the M6+ state, but the M=Mn phase has an anomalously small paramagnetic moment and large cell volume. Neutron powder diffraction data are fitted using an anion‐excess La3MnN5.30 model (space group I4/mcm, a=6.81587(9) Å and c=11.22664(18) Å at 200 K) in which Mn is close to the +7 state. Excess‐anion incorporation into Cs3CoCl5‐type materials has not been previously reported, and this or other substitution mechanisms may enable many other high oxidation state transition metal nitrides to be prepared. [ABSTRACT FROM AUTHOR]

Heavy rare earth elements (HREEs) are critical metals in advanced technologies. Here, we report unusual REE patterns and O–Hf–Nd isotopic compositions of composite granites from the Zhaibei HREE deposit. The complex consists of two Mesozoic granites with ages of 188 and 170 Ma. The older granites are characterized by higher HREE contents and negative Ce anomaly and contain cerianite veinlets. Their REE-rich minerals also show strong Ce depletion, indicating a high oxidation state. Magmatic zircons have variables δ18O (6.1–9.4‰) and εHf(t) (−6 to 0), towards a depleted mantle contribution. Lower δ18O (~5.4 vs 6.6‰) and higher εNd(t) (approximately −3 vs −11) values in the altered apatite rim compared to the core and primary phase result from subduction-derived fluids. In contrast, the younger granites have lower REE contents and lack a Ce anomaly. They show mantle-derived Nd (apatite εNd(t) = 1–2), Hf (zircon εHf(t) = 3–8), and O (zircon and apatite δ18O = 4.6–5.7‰) isotopic compositions. Therefore, we infer that a REE-rich fluid migrated from the flat subducting slab and flushed the subsolidus granitic mush in the Early Jurassic. This caused volatile saturation and degassing, leading to the generation of highly oxidized fluids. These processes may cause temporary oxidizing conditions in post-magmatic hydrothermal stages, resulting in the oxidation of Ce3+ to Ce4+. The resulting Ce fractionation from other REE3+ promoted HREE enrichment in the granites. [ABSTRACT FROM AUTHOR]

Pyrometallurgical slags are a valuable secondary resource for several technologically important critical materials/elements. A promising cost-efficient recovery currently under research depends on the incorporation of the element of interest into a specific compound. This new approach under research to recover these elements from the slag is called the "Engineered Artificial Minerals" (EnAM) concept. Optimization of slag system and cooling conditions potentially allow enrichment of a desired element in only one phase. Studying EnAM-formation requires multi model characterization of the slag at different states of formation. This includes bulk as well as microscopic elemental, structural, and species analytical tools and modeling approaches. Here, a characterization strategy mainly studying the formation of potential EnAMs for the recovery of lithium from battery recycling slags is reviewed. LiAlO2 as well as lithium manganates were identified as promising EnAMs. The manganese oxidation state was identified a decisive parameter. For a knowledge-based design of slags, it is necessary to understand the processes leading to oxidation state variability. Hence, besides structural, compositional characterization, speciation of redox active elements is discussed here using molecular dynamics simulations, powder X-ray diffraction, electron probe microanalysis, X-ray absorption near edge structure, micro-X-ray fluorescence, micro-X-ray diffraction, and micro-X-ray absorption near edge structure. [ABSTRACT FROM AUTHOR]

Multifunctional N, Fe-doped carbon dots (N, Fe-CDs) were synthesized by the one-step hydrothermal method using ferric ammonium citrate and dicyandiamide as raw materials. The N, Fe-CDs exhibited peroxidase-like (POD) activity by catalyzing the oxidization of 3,3′,5,5′-tetramethylbenzidine (TMB) to the green oxidation state ox-TMB in the presence of hydrogen peroxide (H2O2). Subsequently, based on the POD activity of N, Fe-CDs, an efficient and sensitive colorimetric method for the detection of H2O2 and ascorbic acid (AA) was established with a limit of detection of 0.40 µM and 2.05 µM. The proposed detection method has been successfully applied to detect AA in fruit juice, vitamin C tablets, and human serum samples and has exhibited excellent application prospects in biotechnology and food fields. Furthermore, N, Fe-CDs also showed a protective effect on the cell damage caused by H2O2 and could be used as an antioxidant agent. [ABSTRACT FROM AUTHOR]

Manganese oxides (MnxOy) are considered a promising cathode material for aqueous zinc-ion batteries (AZIBs) due to their high theoretical specific capacity, various oxidation states and crystal phases, and environmental friendliness. Nevertheless, their practical application is limited by their intrinsic poor conductivity, structural deterioration, and manganese dissolution resulting from Jahn–Teller distortion. To address these problems, doping engineering is thought to be a favorable modification strategy to optimize the structure, chemistry, and composition of the material and boost the electrochemical performance. In this review, the latest progress on doped MnxOy-based cathodes for AZIBs has been systematically summarized. The contents of this review are as follows: (1) the classification of MnxOy-based cathodes; (2) the energy storage mechanisms of MnxOy-based cathodes; (3) the synthesis route and role of doping engineering in MnxOy-based cathodes; and (4) the doped MnxOy-based cathodes for AZIBs. Finally, the development trends of MnxOy-based cathodes and AZIBs are described. [ABSTRACT FROM AUTHOR]