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[Display omitted] • Mining seawater C a 2 + and M g 2 + for recovering F - was proposed. • This was achieved through the high affinity between carboxyl and C a 2 + / M g 2 + . • The C a F 2 / M g F 2 colloids were recovered and retained by the filter papers. • Additional flocculation was avoided. Resource reclamation with low carbon emissions is highly desirable from the perspective of the circular economy. We propose a green solution in this study, which involves mining calcium and magnesium from seawater as an effective reagent for the recovery of valuable fluoride. This was achieved by esterifying the cellulose filter papers with citric acid to associate carboxyl groups onto their surfaces. Consequently, the high affinity between the carboxyl group and alkaline earth elements enabled efficient and selective loading of C a 2 + (0.193 ± 0.001 mmol- C a 2 + /g) and M g 2 + (0.127 ± 0.001 mmol- M g 2 + /g) onto the filter papers, reaching up to 96% and 60% of the available active sites, respectively. When applied in natural seawater, the esterified filter papers successfully captured both C a 2 + (0.110 ± 0.007 mmol- C a 2 + /g) and M g 2 + (0.078 ± 0.005 mmol- M g 2 + /g) simultaneously. The presence of IR singlet symmetric (ν s COO, ≈ 1450 cm−1) stretching vibrations indicated that both C a 2 + and M g 2 + ions were complexed with carboxyl groups in a bridging unidentate mode. The adsorption capacity of C a 2 + and M g 2 + was likely influenced by the varying thickness of their hydration shells within the highly overlapped electric double layers presented in the micropores of the esterified filter papers. The papers loaded with C a 2 + and M g 2 + were subsequently utilized for fluoride recovery in simulated HF wastewater. The formation of C a F 2 / M g F 2 colloids effectively recovered the stoichiometric amount of fluoride (C a F 2.46 and M g F 1.72), which were retained on the surface of the filter papers. Additional flocculation for colloid separation is thus avoided, resulting in a significant increase in the content of reclaimed fluoride. Increasing the density of associated carboxyl groups is crucial for effectively complexing a greater amount of seawater C a 2 + / M g 2 + and, consequently, enhancing the capacity of fluoride reclamation by esterified filter papers. [ABSTRACT FROM AUTHOR]

Among the various waste-to-energy conversion methods, gasification is a technically feasible option for municipal solid waste valorization, meeting current emission limits and reducing landfill disposal burden. This work investigates the potential of paper rich (⁓ 76 % wt.) commercial refuse-derived fuel (RDF) having high ash content (⁓ 17 % wt.) for gasification and co-gasification in downdraft gasifier. The ash formed from RDF, with higher proportion of alkaline earth metals (Ca and Mg) and lower proportion of alkali metals (Na and K), can effectively avoid agglomeration and clinker formation during gasification. The producer gas obtained from RDF gasification reports a maximum lower heating value of 4.34 MJ/Nm3at an equivalence ratio of 0.34 with corresponding cold gas efficiency of 59.24%.Co-gasification of RDF with biomass was examined as a strategy to reduce overall ash content of the mixture, using sawdust. Co-gasification has exhibited a synergy between RDF and sawdust when the RDF fraction in feedstock is at the higher side. A maximum lower heating value of 4.65 MJ/Nm3 was obtained during the co-gasification and the tar yield reduced from 13.6 g/Nm3to 8.8 g/Nm3 when RDF in the feed increased from 25% to 75% (w/w). • Investigates potential of paper-rich RDF for gasification and co-gasification. • Absence of agglomeration and clinker formation during gasification and co-gasification. • Producer gas with LHV and CGE of 4.34 MJ/Nm3 and 59.24%, respectively from RDF gasification. • RDF has exhibited synergy with biomass at higher RDF fraction during co-gasification. • Reduction in tar content with increase in RDF fraction during co-gasification. [ABSTRACT FROM AUTHOR]

The dephosphorization behavior of multiphase steel slag in converter steelmaking process is very important for higher steel quality with ultra-low phosphorus content. In this paper, the multiphase steel slag with different BaO content reacted with hot metal at 1873 K temperature. The influence of the reaction on dephosphorization was investigated. The mineralogical phase was observed. The phosphorus partition between phosphorus enriched phase and liquid phase was discussed. The phosphorus partition ratio between steel slag and hot metal was obtained. The main mineralogical phases of steel slag were phosphorus enriched phase mCa2SiO4-Ba1-xCax(PO4)2 and RO (FeO/MgO) phase. The barium existed in phosphorus enriched phase and liquid phase, not in RO phase. The phosphorus content in phosphorus enriched phase increased from 1.12% to 1.36% with the addition of BaO. The phosphorus partition ratio between phosphorus enriched phase and liquid phase increased from 2.60 to 3.77, increased 45.00% by the addition of BaO. The phosphorus partition ratio between steel slag and hot metal increased from 55.35 to 97.50, increased 76.15% by the addition of BaO in steel slag. [ABSTRACT FROM AUTHOR]

Introducing post-transition metal cations is an excellent strategy for enhancing optical properties. This paper focuses on four isomers, namely the X2PO4I (X = Pb, Sn, Ba, and Sr) series. For the first time, the paper's attention is paid to the changes in electronic structure, as well as refractive indices and birefringence, with and without the inclusion of spin–orbit effects in this series. The first-principles results show that spin–orbit effects of the 5p and 6p states found in these compounds lead to splitting of the bands, narrowing of the band gap, enhancement of the lone-pair stereochemistry, and enhancement of the refractive indices and birefringence. Moreover, a comparison of the lone-pair electron phosphates, X2PO4I (X = Pb and Sn), and the isomeric alkaline earth metal phosphates, X2PO4I (X = Ba and Sr), reveals that changes in the band structure have a greater effect on the enhancement of the birefringence than the slight enhancement of the lone-pair stereochemical activity. This study has important implications for a deeper understanding of the optical properties of crystals and the design of novel optical materials. [ABSTRACT FROM AUTHOR]

The contents of alkali and alkaline earth metals are higher in Zhundong coal, and there are serious problems of slagging and fouling during the combustion process. Therefore, it is of great significance to reveal the mechanism of slagging and fouling in the boiler of Zhundong coal. In this paper, first-principle calculations based on density functional theory are used to study the competition mechanism of alkaline metal oxides during the combustion process in Zhundong coal by establishing the Na2O(110)/CaO(100)-SiO2(100) double-layer interface model. The results show that the bond lengths of the surface of Na2O(110) and CaO(100) with SiO2(100) after adsorption were generally lengthened and the value of bond population became smaller, which formed a stable binding energy during the reaction. The electron loss of Na is 0.05 e, the electron loss of Ca is 0.03 e, and the electron loss of Na2O is greater than that of CaO. The charge transfer on the surface of Na2O with SiO2 is obviously higher than that of CaO and the orbital hybridization on the surface of CaO with SiO2 is weaker than that on the surfaces of Na2O with SiO2. Na2O is easier to react with SiO2 than CaO. The adsorption energies on the surface of Na2O and CaO with SiO2 are −5.56 eV and −0.72 eV, respectively. The adsorption energy of Na2O is higher than that of CaO, indicating that Na2O is more prone to adsorption reactions and formation of Na-containing minerals and other minerals, resulting in more serious slagging. In addition, the XRD analyses at different temperatures showed that Na-containing compounds appeared before Ca-containing ones, and the reaction activity of Na2O is stronger than that of CaO in the reaction process. The experimental results have good agreement with the calculation results. This provides strong evidence to reveal the slagging and fouling of Zhundong coal. [ABSTRACT FROM AUTHOR]

The treatment of cancer has always been a challenging problem in the medical community. In this paper, based on density functional theory (DFT), B12N12 nanocage was studied as delivery carriers of sulforaphane (SF) anticancer drug, and the adsorption properties, electronic properties and topological analysis of complexes were calculated. The adsorption energy, solvation energy, electronic and topological properties were calculated by used M06-2X/6-311+G(2d,p), M05-2X/6-31G(p) and B3LYP/6-311G(d,p) theoretical levels, respectively. In addition, the effects of doping and packaging of alkaline earth metal (Be, Mg, Ca) on the related properties were also studied. Doping and packaging metal can improve the transfer characteristics of nanocages by changing the polarity of systems. All calculation results were performed in Gaussian 09 software. The frontier molecular orbital (FMO) and natural bond orbital (NBO) analysis showed that nanocages acting as charge acceptors and drugs as charge donors during the adsorption process. The atoms-in-molecules (AIM) and interaction region indicator (IRI) analysis showed that there were strong polar covalent bonds between drug and nanocages, which enabled drug to be stably adsorbed on nanocages. The solvation effect results showed that acidic conditions were more conducive to drug transport and release. Compared with the original and encapsulated systems, the doping system has better adsorption properties and solvation effect. Moreover, the charge transfer between drug and nanocages in doping system was more frequent and the interaction was stronger. Therefore, our results indicated that the doping nanocages MB11N12 (M = Be, Mg and Ca) were more suitable as the drug carrier system for SF anticancer drug. [ABSTRACT FROM AUTHOR]

This paper represents a simplistic hydrothermal method for the synthesis of lanthanide (Ln3+)-doped (Ln= Eu, Dy) alkaline earth metal fluoride, i.e., CaF2 nanocrystals coated with poly(acrylic acid) (PAA). The structural and optical characterization of as-prepared nanocrystals is performed using scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), Fourier transform infrared spectrum (FTIR), thermogravimetric analysis (TGA), photoluminescence spectroscopy (PL), and PL lifetime measurements. It is observed that CaF2 exhibits strong red emission when doped with Eu3+ (5 mol%) ions, whereas it shows strong blue and yellow emission when doped with Dy3+ (2 mol%) ions. PAA coating helps to enhance the stability as well as water dispersibility of the nanocrystals. Moreover, this method can be extended to make other lanthanide-doped alkaline earth metal fluoride nanocrystals. The high photoluminescence efficiency and water solubility of the nanocrystals make the material to be used in many fields of optical devices as well as biological applications. [ABSTRACT FROM AUTHOR]

This article discusses the preparation of radiopure lithium carbonate powder for low-background research, specifically for the AMoRE-II experiment. The desired radiopurity for the lithium powder is specified, and commercially available powders were found to be unsuitable. A special purification technology was developed to remove contamination from the powder. The article provides details on the analysis results, decontamination efficiency, and purification methods used. The authors are continuing to explore new purification methods to achieve the desired purity for crystal synthesis. The paper was reviewed by researchers from Brookhaven National Laboratory in the United States and Gazi University in Turkey, and edited by a researcher from University College London in the United Kingdom. [Extracted from the article]

The paper reports on effect of grain-growth inhibitors MgO, Y2O3 and MnCO3 as well as Ca modification on the microstructure, dielectric, ferroelectric and electrocaloric (EC) properties of Ba0.82Sr0.18Sn0.065Ti0.935O3 (BSSnT). Furthermore, the effects of the sintering time and temperature on the microstructure and the electrical properties of the most promising material system Ba0.62Ca0.20Sr0.18Sn0.065Ti0.935O3 (BCSSnT-20) are investigated. Additions of MgO (xMgO = 1%), Y2O3 (xY2O3 = 0.25%) and MnCO3 (xMnCO3 = 1%) significantly decreased the mean grain size of BSSnT to 0.4 µm, 0.8 µm and 0.4 µm, respectively. Ba0.62Ca0.20Sr0.18Sn0.065Ti0.935O3 (BCSSnT-20) gained a homogeneous fine-grained microstructure with an average grain size of 1.5 µm, leading to a maximum electrocaloric temperature change |ΔTEC| of 0.49 K at 40 °C with a broad peak of |ΔTEC| > 0.33 K in the temperature range from 10 °C to 75 °C under an electric field change of 5 V µm−1. By increasing the sintering temperature of BCSSnT-20 from 1350 °C to 1425 °C, the grain size increased from 1.5 µm to 7.3 µm and the maximum electrocaloric temperature change |ΔTEC| increased from 0.15 K at 35 °C to 0.37 K at 20 °C under an electric field change of 2 V µm−1. Our results show that under all investigated material systems, BCSSnT-20 is the most promising candidate for future application in multilayer ceramic (MLC) components for EC cooling devices. [ABSTRACT FROM AUTHOR]

Heavy-atom alkaline earth monofluoride molecules are considered as prospective systems to study spatial parity or spatial parity and time-reversal symmetry violating effects such as the nuclear anapole moment or the electron electric dipole moment. A comprehensive and highly accurate theoretical study of the electronic structure properties and transition energies in such systems can simplify the preparation and interpretation of the experiments. However, almost no attempts to calculate quantum electrodynamics (QED) effects' contribution into characteristics of these neutral heavy-atom molecules have been performed. Recently, we have formulated and implemented such an approach to calculate QED contributions to transition energies of molecules [L. V. Skripnikov, J. Chem. Phys. 154, 201101 (2021)]. In this paper, we perform a benchmark theoretical study of the transition energies in the Ba+ cation and BaF molecule. The deviation of the calculated values from the experimental ones is of the order 10 cm−1 and is more than an order of magnitude better than the "chemical accuracy," 350 cm−1. The achievement of such an agreement has been provided, in particular, by the inclusion of the QED effects. The latter appeared to be not less important than the high-order correlation effects beyond the coupled cluster with single, double, and perturbative triple cluster amplitude level. We compare the role of QED effects for transition energies with heavier molecules—RaF and E120F, where E120 is the superheavy Z = 120 homolog of Ra. [ABSTRACT FROM AUTHOR]

Co-combustion is a crucial route for the high-efficiency utilization and clean conversion of different carbonaceous feedstocks (biomass, coal, petroleum coke, etc.). The migration and transformation of alkali and alkaline earth metals (AAEMs) are not only related to ash-related issues in actual application, but also directly affect the reaction behavior of binary particles during co-conversion. This review paper summarizes research progress in the detection methods (online and offline) and influencing factors (feedstock type, feedstock blending ratio, reaction temperature, reaction time) of AAEMs migration and transformation during the co-combustion of carbonaceous feedstocks. Furthermore, it provides a detailed summary of research progress on factors (feedstock blending ratio, heating rate, etc.) influencing the co-combustion reactivity of carbonaceous feedstocks, synergy behavior, and its mechanisms. The influence of feedstock type on AAEMs migration and transformation during co-combustion is mainly related to the composition categories, chemical forms and contents of intrinsic mineral in binary feedstocks. The increase in the combustion temperature will intensify the release of inherent AAEMs in carbonaceous feedstocks, and promote AAEM deactivation. For high K and Cl-containing biomass, a higher biomass proportion in blends would result in more AAEMs release during the co-combustion process. Conversely, an increase in coal proportion in blends will directly favor the reduction or inhibition of AAEMs release. Synergy behavior during co-pyrolysis and subsequent char co-combustion is usually presented as an inhibition effect and an synergistic effect, respectively. The synergistic mechanisms of carbonaceous feedstock co-combustion reactions can be divided into two categories: non-catalytic synergistic mechanisms related to the excitation and migration of biomass-based free radicals and catalytic synergistic mechanisms related to biomass-based AAEMs catalysis. Additionally, future research prospects are also proposed based on the systematic review. [ABSTRACT FROM AUTHOR]

C2+ hydrocarbons, especially C2+ olefins, as important basic chemical raw materials, mainly come from petroleum cracking. With the increasing scarcity of petroleum resources, the search for new olefins production routes has become the focus of research, and the production of olefins by the oxidative coupling of methane (OCM) process has attracted extensive attention. The OCM route is an important alternative to the production of olefins from petroleum resources and is also an important direction for the development of efficient and clean utilization of natural gas. In this paper, the mechanism, catalysts, and other key factors for the production of olefins by methane oxidative coupling are reviewed. The mechanism of OCM, including the reaction pathway and the formation of intermediate products, is introduced. Then, commonly used catalysts, such as alkali metal/alkaline earth metal oxides, rare earth metal oxides, composite metal oxides with special structures, and classical catalysts Mn/Na2WO4/SiO2, and their mechanisms of action in the reaction are discussed. In addition, the application of chemical looping oxidative coupling of methane (CLOCM) in olefin production is also investigated, which is a promising alternative way due to the high selectivity of olefins and the low cost of catalysts owing to the excellent performance of the catalyst recycling. These studies will help to further understand the mechanism of OCM for olefin production and provide guidance and support for applications in related fields. [ABSTRACT FROM AUTHOR]

The transition metal properties of heavy alkaline earth metals have been extensively studied, and their neighbouring heavy alkali metals have been limited to the interactions with CO‐σ ligands. Based on this, the complexes [K2M(COT)2]− (M=K, Rb, Cs) interacting with heavy alkali metals and COT‐π ligands are theoretically designed in this paper. The electronic structure analysis showed that the three complexes had 10 occupied molecular orbitals (MOs), in which 8 of them were related to the atomic orbitals (AOs) of central alkali metals, including 4 d orbitals (dxy, dx2−y2, dxz, dyz), so they also exhibited the typical behaviors of transition metals. NBO analysis indicated that the central metals in these complexes are common valence of +1, the ligands are negative, so the electrostatic coulomb interaction between positive and negative ions makes them more stable. This can be reflected by the high binding energies of −585.8 to −594.0 kcal/mol, which are much higher than those of −6.5 to −63.3 kcal/mol for the trace amount of complexes combined by neutral metals and ligands. It would be a feasible strategy for the design of the macrosynthesis of related complexes by combining the positive ions and negative ligands, which can stabilize the complexes through the favorable Coulomb attractions. [ABSTRACT FROM AUTHOR]

In this paper, the removal behavior of alkali and alkaline earth metals (AAEMs) and the evolution of microscopic characteristics in high alkali coal under the leaching of inorganic and organic acids are studied. The results show inorganic acids have better effect on the removal of AAEMs because of their stronger ability to convert carboxylate and phenol salts into covalent carboxylic acids and phenols. Citric acid has a slightly weaker effect than inorganic acids, and oxalic acid has the least effect. The improvement of slagging characteristics is consistent with the removal ability. Sulfuric acid, hydrochloric acid and citric acid are more effective in enhancing the calorific value of coal, with an enhancement of about 0.60 MJ/kg. After leaching, the pores and cracks in the coal are developed, and the mesopores have a tendency to shift to a lower pore size range. This trend is most pronounced in citric acid leached coal and hydrochloric acid leached coal. Sulfuric acid seriously damage the surface morphology, which results in a tendency of large pore transfer in S-form coal. [ABSTRACT FROM AUTHOR]

High‐temperature piezoelectric sensing is usually used in the aerospace, automotive, and power plant fields. High temperature piezoelectric ceramics are considered the key materials in these fields. In this paper, Ca1−x(Ba1/2Sr1/2)xBi2Nb1.985(W3/4Mn1/4)0.015O9 (x = 0.05, 0.10, 0.15 and 0.20) (C1−xBSxBNWM) has been synthesized by a traditional solid state reaction method. The effects of substitution of calcium at the A‐site by barium and strontium on phase evolution and piezoelectric properties of the CaBi2Nb2O9 orthorhombic Aurivillius phases were investigated. The crystal structure of piezoelectric ceramics was characterized by XRD, Rietveld refinement, and Raman spectroscopy. Co‐substitution of barium/strontium (Ba2+/Sr2+) and tungsten/manganese (W6+/Mn4+) resulted in lattice distortion of C1−xBSxBNWM ceramics. The results induce that the tetragonal crystal structure increase with increasing the co‐substitution cations. Isothermal impedance spectroscopy confirmed intrinsic thermally activated conduction in the system. The C1−xBSxBNWM ceramics with x = 0.15 exhibit a very high Curie temperature (TC ∼ 923°C), a reasonable piezoelectric coefficient (d33 = 13.3 pC/N). Remarkably, even after thermal annealing at temperatures up to 800°C, it still retains a high d33 of 13 pC/N. In addition, the C0.85BS0.15BNWM ceramic had a relatively high resistivity (3.82 × 106 Ω·cm, 500°C). The Ca0.85(Ba1/2Sr1/2)0.15Bi2Nb1.985(W3/4Mn1/4)0.015O9 ceramics make possible their application in high‐temperature acceleration transducers. [ABSTRACT FROM AUTHOR]

In recent years, the application of Bi3+ ions doped luminescent materials in the field of optoelectronics has attracted wide attention. In this paper, CaLaGaO 4 :xBi3+(x = 0.005, 0.0075, 0.01, 0.0125, 0.015, 0.02, 0.025mol) blue phosphors were synthesized by high temperature solid phase method. The theoretical and experimental bandgap values after Bi3+ ions doping is reduced, indicate that electrons can be transferred from valence band to conduction band better after Bi3+ ions doping, which increases the carrier concentration and improves the luminous efficiency. In addition, due to the doping of Li+ ions under 365 nm excitation, the emission intensity is increased by 2.5 times, shows high brightness blue light, with excellent thermal stability (423K/303K = 83 %), quantum efficiency is 56 %, and CaLaGaO 4 :0.01Bi3+, 0.008Li+ phosphor was mixed with (Ba,Sr) 2 SiO 4 :Eu2+ commercial green phosphor and (Ca,Sr)AlSiN 3 :Eu2+ red phosphor in a certain proportion. The WLED combined with 365 nm chip has a high color rendering index Ra = 90.2. Relevant color temperature CCT = 5502K. [ABSTRACT FROM AUTHOR]

The exploration of nonlinear optical crystals with ultraviolet (UV) transparent ranges and easy-to-grow large-size crystals is one of the current research interests. Herein, by combining borate and phosphate groups, a novel congruently melting alkali-mixed metal borophosphate, Li3Na7B4P6O26 (LNBPO) with UV transparency was successfully designed and synthesized using a high-temperature flux method. LNBPO crystallizes in the non-centrosymmetric (NCS) and polar orthorhombic space group Pca21 (no. 29), showcasing interesting (B2P3O13)∞ chains along the c axis. Notably, LNBPO has a moderate second harmonic generation (SHG) response (∼0.38 × KDP) and displays a wide transmission ranging from 0.22 to 3.68 μm, as measured by a [001]-oriented crystal wafer. Furthermore, a high-quality single crystal of LNBPO with sizes up to 14 × 14 × 12 mm3 was grown using the top-seeded solution growth method. The refractive indices of LNBPO were determined by applying the minimum deviation angle method. These results show that LNBPO possesses a phase-matching wavelength as short as 483 nm, indicating its potential as a new UV NLO crystal. [ABSTRACT FROM AUTHOR]

In this work, PbSb2O6-type oxides LaMTeO6 (M = Ga3+ and Mn3+) were synthesized and structurally characterized by Rietveld refinements against high-resolution X-ray powder diffraction data. The Ga3+/Te6+ partial ordering within the honeycomb-like two-dimensional [GaTeO6]3− anionic layer leads to the loss of the inversion center between Ga3+ and Te6+; however the inversion center on the 3¯-roto-inversion axis is preserved, thereby resulting in a 2-fold PbSb2O6-type superstructure by doubling the c-axis associated with a structural symmetry descending from the original P3¯1m to P3¯1c symmetry. In contrast, LaMnTeO6 (P21/c) adopts a monoclinically distorted 4-fold superstructure with lattice dimensions of a ≈ aH, b ≈ √3aH, c ≈ 2cH, where aH and cH represent the lattice parameters of trigonal PbSb2O6. The formation of this P21/c-superstructure is attributed to the combination of complete Mn3+/Te6+ ordering and the first-order Jahn–Teller distortion of Mn3+ with the electronic configuration of d4. Such a monoclinic distortion can effectively lift the Mn3+ spin moments arranged on the triangular sublattice, resulting in a sharp peak for antiferromagnetic transition, which is in stark contrast to subtle magnetic transitions for PbSb2O6-type tellurates AMn(VI)TeO6 (A = alkaline earth and Pb2+) and LnCrTeO6 (Ln = rare earth) with higher structural symmetry. Our findings highlight that the electronic configuration effects of M-cations play a critical role in controlling the structure symmetry of LaMTeO6, providing a strategy to fine-tune the crystal structures and physical properties. [ABSTRACT FROM AUTHOR]

The effects of single‐vacancy and double‐vacancy doping with alkaline‐earth metals on the stability, electronic structure, charge transfer, and optical properties of molybdenum ditelluride in the monolayer defective state (MoTe2) have been investigated using first‐principles methods. It is found that the structure of the molybdenum ditelluride system is more stable after double Te vacancies, with direct band‐gap to indirect band‐gap transitions occurring in single Te vacancies and Mo vacancies, and semiconductor to quasi‐metal transitions occurring in double Mo vacancies. The binding energy in the defect state system of molybdenum ditelluride after vacancy defects is always negative, and the structure remains stable. In this paper, the most stable double Te vacancy state was selected for substitutional doping with alkaline‐earth metals, and the Be atoms were doped with the largest amount of morphology, and Ca atoms were doped with the most pronounced decrease in band gap value. The direct band‐gap semiconductor is maintained after doping with Be atoms. Doping with Mg, Sr and Ba changes the band‐gap from direct to indirect. The double Te defect state MoTe2 doped with Ca atoms has a tendency to transition to a quasi‐metal. Regarding photoelectric properties, the system is blue‐shifted on both the absorption and reflection peaks. [ABSTRACT FROM AUTHOR]

In this study, three different solvent systems have been employed to investigate the effect of reaction parameters on the synthesis of four alkaline earth metal-based MOFs namely [Ca(0.5 1,4-phenyl diacetic acid)2(H2O)DMF]∞ (Ca-MOF-1), [Ca(1,4-naphthalene dicarboxylate)DMF]∞ (Ca-MOF-2), [Ca2(0.5 1,2,4,5-benzene tetracarboxylate)2(H2O)3DMF]∞ (Ca-MOF-3) and [Ca2(2,6-naphthalene dicarboxylate)2(H2O)6]∞ (Ca-MOF-4). The crystal structures of these four MOFs have been resolved through single crystal X-ray analysis and the bulk phase purity of these MOFs was assessed using PXRD and FT-IR analysis. To check the stability of these MOFs, thermogravimetric analysis (TGA) was carried out. To analyze the robustness of these MOFs, the PXRD of the samples was also collected at different pH levels. These MOFs were further explored as Lewis acid catalysts for the alcoholysis of epoxides and the activity of these catalysts depend on the open metal sites present in the MOFs. The catalytic activity follows the order: Ca-MOF-2 > Ca-MOF-4 > Ca-MOF-1 > Ca-MOF-3. The activity was also checked with various epoxide substrates using Ca-MOF-2. Density functional theory (DFT) calculations also support this trend with the help of the thermodynamic feasibility of epoxide binding, considering model MOF structures. The weak interaction between the epoxide oxygen and the metal centre of the most stable MOF structure has also been clarified by computational studies. [ABSTRACT FROM AUTHOR]

By introducing the d0 metal cation Mo6+ into phosphates, two new molybdophosphates, K2MgMoP2O10 and K3Mg2MoP3O14, were synthesized by spontaneous crystallization, and their structures were determined by single-crystal X-ray diffraction. K2MgMoP2O10 shows a two-dimensional layer composed of the uncommon eight-membered ring [Mo2P2O16] formed by [MoO6] and [PO4], while K3Mg2MoP3O14 shows isolated [MoP3O14] clusters composed of [MoO5] and [PO4]. K2MgMoP2O10 and K3Mg2MoP3O14 have UV cut-off wavelengths of 277 and 271 nm, respectively, which are significantly shorter than those of most recently published molybdophosphates. To the best of our acknowledge, K2MgMoP2O10 exhibits the largest birefringence (a calculated value of 0.187 at 546 nm) among reported alkali metal or alkaline earth metal molybdophosphates, which provides a way to explore new birefringent materials. First-principles analysis of the electronic structure shows that the large birefringence of K2MgMoP2O10 mainly originates from the [MoO6] units. [ABSTRACT FROM AUTHOR]

One of the most vulnerable issues in the technical protection of information is to obtain data via leakage through the opto-electronic channel. In this paper, studies of the protective capabilities of glass from laser sounding depending on its elemental composition were carried out using such indicators as the coefficients of reflection and absorption of the laser beam by the window glass. As a result of the work, an experimental installation based on a continuous solid-state laser was assembled. The study of the elemental composition of window glass, which is produced by modern industry, X-ray fluorescence method and the study of the coefficients of reflection and absorption of glass samples in the experimental setup showed that the studied window glass chemically belongs to quartz (silicate). All chemical elements involved in its formation can be divided into 3 groups: glass-forming, transitional, modifiers, which affects the optical properties of the studied glasses, as the elements used have different not only qualitative but also quantitative parameters. Absorption increases if the number of chemical elements that exhibit amphoteric and non-metallic properties and have (-charge) decreases, and increases if the number of chemical elements in the glass that exhibit the most alkaline, alkaline earth properties and in which the radius of cations (+ions) increases. Systematization of the elemental and quantitative composition of the studied window glass in accordance with the periods and groups of the periodic table of chemical elements, enabled the relationship between the electronic structure of chemical elements and the protective properties of glass. [ABSTRACT FROM AUTHOR]

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Fully densified (transparent) ceramic with small grain size is highly desired to improve the field breakdown strength (BDS) and its scattering. Sintering behavior, microstructural evolution, electric, dielectric, and energy storage properties of (Ba0.6Sr0.4)1‐1.5xBixTi1‐x(Mg1/3Nb2/3)xO3 (x =.04–.10) ceramics have been studied in this paper. Phase pure cubic perovskite is observed for the x =.04 composition. Nb‐rich tungsten bronze type and Ti‐rich barium titanate secondary phases are present in the x >.05 compositions. A multiphasic transparent ferroelectric ceramic with ∼74.2% (780 nm) transmittance and a high refractive index of ∼2.3 within the visible region could be successfully obtained for the x =.10 composition by traditional ceramic process. The x =.09 composition demonstrates good energy storage performance (recoverable energy density Wrec = 3.74J/cm3, efficiency η = 77% and BDS = 390kV/cm) with extremely low scattering in BDS, suggesting potential application in large sized energy storage capacitor. [ABSTRACT FROM AUTHOR]

This paper investigates a wide‐band emitting red phosphor, an advancement that solves shortcomings including the re‐absorption of the yellow phosphor in the blue light area and a lack of red spectrum components which result in low color rendering and an uneven white light tone. An examination through femtosecond, Raman, and low‐temperature spectroscopy demonstrates why this phosphor has large Stokes shift (SS = 7.5×103 cm−1) and wide half‐peak width with a full‐width at half maximum (FWHM) of more than 170 nm. In these samples, it is importantly observed that larger lattice causes smaller electron–phonon coupling of Eu2+ activator, and meanwhile leads to less temperature dependency of emission peak width. The obtained sample, after cation replacement in (Ca1‐xSrx)7(SiO3)6Cl2: Eu2+ (CSSC: Eu2+), exhibits an emission spectrum covers the range from 450 to 800 nm while its excitation range is below 450 nm, in which not reabsorb the blue light. This matches well with blue phosphors that can also be excited by near‐ultraviolet chips. The fabricated white light‐emitting diode (w‐LED) device has an ideal color rendering index and correlated color temperature (Ra = 90.5, CCT = 3894 K), making it an excellent candidate material for white LED illumination. [ABSTRACT FROM AUTHOR]

Constructing an environmentally friendly and efficient electrocatalyst holds important and profound significance for energy-efficient hydrogen production. Replacing the oxygen evolution reaction with a lower potential urea oxidation reaction (UOR) may save energy in water electrolysis to produce hydrogen. The UOR is characterized by its high energy barrier, which results in slow reaction kinetics. In this study, we introduced Ba(OH)2 into Ni(OH)2 to form uniform nanosheets. Due to the introduction of Ba2+, the lattice expansion of Ni(OH)2 was triggered, leading to significant improvement in UOR activity. The catalyst achieved a current density of 100 mA cm-2 at only 1.316 V and exhibited remarkable stability over time. Density functional theory (DFT) calculations demonstrate that the Ba-Ni(OH)2 site significantly reduces the energy barrier for urea adsorption, intermediate steps, and desorption. This work provides a novel and environmentally friendly strategy for constructing energy-efficient and highly efficient catalysts through the doping of alkaline earth metals. [ABSTRACT FROM AUTHOR]

This paper investigates a wide‐band emitting red phosphor, an advancement that solves shortcomings including the re‐absorption of the yellow phosphor in the blue light area and a lack of red spectrum components which result in low color rendering and an uneven white light tone. An examination through femtosecond, Raman, and low‐temperature spectroscopy demonstrates why this phosphor has large Stokes shift (SS = 7.5×103 cm−1) and wide half‐peak width with a full‐width at half maximum (FWHM) of more than 170 nm. In these samples, it is importantly observed that larger lattice causes smaller electron–phonon coupling of Eu2+ activator, and meanwhile leads to less temperature dependency of emission peak width. The obtained sample, after cation replacement in (Ca1‐xSrx)7(SiO3)6Cl2: Eu2+ (CSSC: Eu2+), exhibits an emission spectrum covers the range from 450 to 800 nm while its excitation range is below 450 nm, in which not reabsorb the blue light. This matches well with blue phosphors that can also be excited by near‐ultraviolet chips. The fabricated white light‐emitting diode (w‐LED) device has an ideal color rendering index and correlated color temperature (Ra = 90.5, CCT = 3894 K), making it an excellent candidate material for white LED illumination. [ABSTRACT FROM AUTHOR]

The Raman and infrared (IR) wavenumbers were computed for the Aurivillius structure ABi4Ti4O15 (ABT) (ACa, Sr, Ba) in an orthorhombic space group (A21am, No. 36, C122v) using normal coordinate analysis. This study aimed to investigate the impact of A‐site cations on vibrational phonons. The analysis of zone center phonons primarily involved numerous stretching and bending bonds, serving as force constants. These force constants were utilized to assign the calculated wavenumbers in the examined phase for the first time. The theoretical findings in this paper exhibited a favorable correlation with the wavenumbers reported in the literature. Comparisons of force constants, bond lengths, and wavenumbers were conducted to elucidate A‐site cation disordering in these intricate compounds. The outcomes indicated that, in the studied complexes, the Sr atom exhibited an ideal radius for fitting into the structure. The mass of the A‐site cations was identified as a factor contributing to tilts in the octahedra. An additional analysis was carried out to assess the impact of A‐cations on both the affected equatorial and axial bonds, providing a clearer understanding of the structure. Outer octahedra displayed greater sensitivity to A‐site cations compared with inner octahedra. A study of potential energy distribution was also conducted in this work to determine the significance of each force constant in all calculated wavenumbers. It was observed that higher wavenumbers were predominantly influenced by vibrations in oxygen atoms, while lower wavenumbers were mainly affected by A‐site cations. Notably, overdamping was observed in the lowest frequency of the BBT compound. [ABSTRACT FROM AUTHOR]

Research into red phosphors with a high color rendering index is particularly compelling, given the absence of a red component in the spectrum of commercial pc-WLEDs, which combine blue LED chips with yellow-emitting YAG:Ce3+ phosphors. Herein, we reported a novel Eu3+ activated Ca3Zn3Te2O12 red-emitting phosphor, synthesized using a conventional high-temperature solid-phase method. The phase and crystal structures were analyzed by powder X-ray diffraction and Rietveld refinement. The optimal excitation peak of the Ca3Zn3Te2O12:Eu3+ phosphor was located at 395 nm, matching those of conventional commercial near-ultraviolet chips. In addition, the Ca3Zn3Te2O12:9%Eu3+ phosphor exhibited good thermal stability, with an activation energy of 0.267 eV, and the CIE color coordinates hardly changed with temperature. Ultimatel, a high-quality white LED device was fabricated by combining Ca3Zn3Te2O12:9%Eu3+ red phosphor, a commercial BaMgAl10O17:Eu2+ blue phosphor, and(Ba,Sr)2SiO4:Eu2+ green phosphor with a 395 nm near-UV chip. Despite a substantial increase in the input current from 20 to 320 mA, the white-LED maintained a stable color rendering index of around 80, highlighting its consistent performance. These results indicated that Eu3+ activated Ca3Zn3Te2O12 phosphors are promising red emission candidates for white LEDs pumped by near ultraviolet chips. [ABSTRACT FROM AUTHOR]

Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) has the advantages of high throughput (simultaneous detection of multiple ions), high separation efficiency (higher than 105 theoretical plates) and rapid analysis capability (less than 5 min for common inorganic ions). A compact CE-C4D system is ideal for water quality control and on-site analysis. It is suitable not only for common cations (e.g. Na+, K+, Li+, NH4+, Ca2+, etc.) and anions (e.g. Cl−, SO42−, BrO3−, etc.) but also for some ions (e.g. lanthanide ions, Pb2+, Cd2+, etc.) that require complex derivatization procedures to be detected by ion chromatography (IC). However, an obvious limitation of the CE-C4D method is that its sensitivity (e.g. 0.3–1 μM for common inorganic ions) is often insufficient for trace analysis (e.g. 1 ppb or 20 nM level for common inorganic ions) without preconcentration. For this technology to become a powerful and routine analytical technique, the system should be made compact while maintaining trace analysis sensitivity. In this study, we developed an all-in-one version of the CE-C4D instrument with custom-made modular components to make it a convenient, compact and high-performance system. The system was designed using direct digital synthesis (DDS) technology to generate programmable sinusoidal waveforms with any frequency for excitation, a kilovolt high-voltage power supply for capillary electrophoresis separation, and an "effective" differential C4D cell with a low-noise circuitry for high-sensitivity detection. We characterized the system with different concentrations of Cs+, and even a low concentration of 20 nM was detectable without preconcentration. Moreover, the optimized CE-C4D setup was applied to analyse mixed ions at a trace concentration of 200 nM with excellent signal-to-noise ratios. In typical applications, the limits of detection based on the 3σ criterion (without baseline filtering) were 9, 10, 24, 5, and 12 nM for K+, Cs+, Li+, Ca2+, and Mg2+, respectively, and about 7, 6, 6 and 6 nM for Br−, ClO4−, BrO3− and SO42−, respectively. Finally, the setup was also applied for the analysis of all 14 lanthanide ions and rare-earth minerals, and it showed an improvement in sensitivity by more than 25 times. [ABSTRACT FROM AUTHOR]

In this paper, we present the results of a comprehensive study of six eclipsing binaries whose components are confirmed or suspected Am stars. By combining long-term, high-resolution Catania Astrophysical Observatory Spectropolarimeter (CAOS) spectroscopy and TESS photometry, we have been able to accurately obtain the orbital parameters of each system as well as the atmospheric parameters of its components. We performed an in-depth chemical analysis and provided chemical abundances of C, O, Na, Mg, Si, Ca, Sc, Ti, Cr, Mn, Fe, Ni, Zn, Sr, Y, Zr, and Ba. From the solution of the light and radial curves, we have determined the masses, radii, and temperatures with a good degree of accuracy. We observe apsidal motion in the eccentric system HD 216429, in which the Rossiter-McLaughlin effect is also noted. We inferred the age of our targets by fitting isochrones on the HR diagram and find that both components in each system are properly described with the same isochrone, which reinforces our results. Furthermore, dynamical and evolutionary masses, independently obtained, show an excellent agreement. According to the out-of-eclipse variability shown in their TESS light curves and their position on the Hertzsprung-Russell diagram, we claim that the stars HD 42954 (as δ Sct type) and HD 151604 (γ Dor) have a pulsating nature. Based on the chemical analysis, we corroborate that four of the systems studied here are formed by Am stars, while in the remaining ones (HD 126031 and HD 216429) only the primary component exhibits a peculiar composition. Additionally, the age distribution found in Am stars supports their suitability as age tracers in stellar populations. [ABSTRACT FROM AUTHOR]

Water is known to play a crucial role in the generation of many large igneous provinces (LIP) worldwide, but the amount and origin of the water in their sources is still under debate. To address this question, this paper presents in situ major-, trace-element, and Sr isotope data coupled with bulk-mineral O-HHe isotope analyses of amphibole in a suite of aillikites from the Tarim LIP (NW China). The cores of zoned macrocrysts and microcrysts display partially overlapping compositions ranging between edenite and pargasite (75-83 versus 75-80 Mg#), which suggest a common origin from an evolving magma. The rims (Mg# = 75-80) of both macrocrysts and microcrysts are very similar to their cores for many elements, except for higher Sr and Ba contents. All the amphibole zones show similar primitive mantle-normalized trace element patterns, suggesting that they crystallized at different stages during magmatic evolution. This interpretation is confirmed by the homogenous Sr isotope compositions (87Sr/86Sr(i) = 0.70298-0.70394) of these amphiboles, which overlap with those of magmatic apatites and perovskites in these aillikites. The hydrogen isotope compositions (-D = -120‰ to -140‰) of the amphiboles are significantly lower than average mantle values. Given the low water contents (<0.66 wt%) of these minerals, the low H iso signatures of the amphiboles might be caused by variable H2O loss during magma ascent. However, open-system Rayleigh fractionation modeling suggests that the hydrogen isotope compositions of these amphibole phenocrysts cannot be fully reproduced by crystallization following magmatic degassing. These low Î'D values require incorporation of recycled altered oceanic crust containing hydrous components in the plume source of these aillikites, which is consistent with the previously published moderately radiogenic He isotope ratios of olivine separates and bulk-rock Os and Pb isotope data for these same samples. We conclude that water in these magmas was derived from a plume source containing recycled water-bearing oceanic crust. [ABSTRACT FROM AUTHOR]

Sensitive and high-throughput analysis of trace elements in biological samples with limited volume is of great significance for clinical studies. However, traditional analysis methods often require complex sampling systems, leading to large sample consumption and hindering the rapid detection of trace samples. In this study, we have developed a simple, sensitive and portable droplet cathode glow discharge (DCGD) array for the rapid analysis of micro-volume serum samples. It requires only 10 μL of sample and utilizes a pipette gun for sample introduction, eliminating the need for pumps and valves in conventional solution discharge systems. The triggering and signal acquisition of each droplet sample can be completed within 300 ms, enabling the detection of approximately 240 samples per hour using the droplet array DCGD-OES. Under optimized conditions, the detection limits for Li, Ca and K were determined to be 0.002 mg L−1 (20 pg), 0.078 mg L−1 (780 pg), and 0.005 mg L−1 (50 pg), respectively. The accuracy of the proposed DCGD-OES method was verified through the analysis of two certified standard substances (Seronorm serum L-1 and L-2 RUO) and 20 real human serum samples, and the obtained relative standard deviation (RSD) is approximately 5% (n = 5). The results demonstrate that the low-cost, low-power DCGD-OES offers a promising and reliable approach for the rapid and high-throughput detection of Li, Ca, K and other important elements in volume-limited serum samples. [ABSTRACT FROM AUTHOR]

Nickel isotopes have been employed to trace various processes such as the weathering of mafic and ultramafic rocks, mineral adsorption and co-precipitation, and the metabolism of methanogenic archaea. Nickel isotopes have displayed significant potential for application, regardless of whether the processes occur at high or low temperatures. However, the currently employed nickel isotope separation methods have certain limitations in terms of separation effectiveness, blank contribution, separation efficiency, and cost-effectiveness of the resin used. Therefore, in this study, we have devised a user-friendly three-step chromatographic procedure that relies on the Chelex-100 resin and other resins for the efficient isolation and purification of nickel from a wide array of geological samples. The three resins utilized in this procedure are Chelex-100, AGMP-1M, and AGMP-50. It is worth noting that Chelex-100 has exhibited exceptional performance in eliminating alkali metals, alkaline earth metals, and iron. Following chromatographic separation, the recovery of nickel surpassed 96%, with a procedural blank below 1.2 ng. To evaluate the procedure's effectiveness, we conducted nickel isotope measurements on nine geological reference materials (BCR-2, GSR-3, GSP-2, NOD-A-1, GSMC-1, SGR-1, SDO-1, GSD-5a, and GSD-23) using MC-ICP-MS. The obtained values were consistent with previously published data, confirming the reliability of our results. The findings of our study establish the applicability of the developed separation procedure for nickel isotope analysis in various geological samples. [ABSTRACT FROM AUTHOR]

The content of alkaline earth metals in Zhundong (ZD) coal ash has a great effect on its melting characteristics. Herein, the influence of MgO content on a silicate microstructure was studied using molecular dynamics simulation under the conditions of 40 mol% high calcium and 20 mol% low calcium. Moreover, the theoretical results were verified by the Fourier transform infrared (FTIR) spectroscopy analysis of synthetic coal ash. In the MgO–CaO–Al2O3–SiO2 system, the results showed that the average bond lengths of Si–O and Al–O in the system are 1.61 and 1.75 Å, respectively, under the high calcium condition. With an increase in MgO content, Q4 with a high degree of polymerization was depolymerized and changed into Q1, Q2 and Q3 with a low degree of polymerization; Ot decreased, Ob increased first and then decreased, and Onb increased. Under the low calcium condition, the average bond lengths of Si–O and Al–O were 1.61 and 1.76 Å, respectively. When the content of MgO increased, Q4 was depolymerized into Q2 and Q3, Ot decreased, Onb increased, and Ob only increased by 1%. Compared with Si4+, Mg2+ easily attacks Al3+, and the degree of damage to the [AlO4]5− tetrahedron is greater. By comparing the distribution of oxygen and the degree of polymerization in the high calcium and low calcium systems, it was concluded that MgO more easily destroys the silicate networks of ash under the condition of high calcium CaO content of 40 mol%, which changes the viscosity and combustion characteristics of the system. [ABSTRACT FROM AUTHOR]

The β-diketiminato calcium and magnesium complexes, [(BDI)MgnBu] and [(BDI)CaH]2 (BDI = HC{C(Me)NDipp}2; Dipp = 2,6-di-isopropylphenyl), react with ortho-carborane (o-C2B10H12) to provide the respective [(BDI)Ae(o-C2B10H11)] (Ae = Mg or Ca) complexes. While the lighter group 2 species is a monomer with magnesium in a distorted trigonal planar environment, the heavier analogue displays a puckered geometry at calcium in the solid state due to Ca⋯H–B intermolecular interactions. These secondary contacts are, however, readily disrupted upon addition of THF to provide the 4-coordinate monomer, [(BDI)Ca(THF)(o-C2B10H11)]. [(BDI)Mg(o-C2B10H11)] was reacted with [NHCIPrMCl] (NHCIPr = 1,3-bis(isopropyl)imidazol-2-ylidene; M = Cu, Ag, Au) to provide [NHCIPrM(o-C2B10H11)], rare C-bonded examples of coinage metal derivatives of unsubstituted (o-C2B10H11)− and confirming the alkaline earth compounds as viable reagents for the transmetalation of the carboranyl anion. [ABSTRACT FROM AUTHOR]

Mesoporous silica-alkali earth (Mg, Ca, or Sr) hybrids were prepared from waste glass as a silica source. Mesoporous silica containing no alkali earth succeeded in preparing a perfect pore structure arranged hexagonally. On increasing the alkali-earth element, mesoporous structures are preserved on a small amount of the alkali-earth element as a substituent and tend to diminish with an increase in the substituent, reducing the surface area. We examined a scale-up experiment for the production of a large amount of hybrids. The scale-up system factor we proposed was relatively small, indicating relatively high production efficiency. The hybrids were also examined for the ion-exchangeability of rare-earth metals. The tendency of the amount for ion-exchange showed a positive convex tetrad effect, which means a decrease in the ionicity of the rare-earth metals during an exchange. Since XANES spectra confirm the trivalent state of each rare-earth metal in ion-exchanged hybrids, the rare-earth metals are found to exchange from the alkali-earth elements because the exchanged amount is 2/3 of the alkaliearth element leached. [ABSTRACT FROM AUTHOR]

There are abundant low-rank coal resources in China. However, its higher AAEMs (alkali and alkaline earth metals) content and the release of AAEMs during combustion cause serious fouling and slagging problems. In this paper, a method of removing AAEMs and ash from low-rank coal to produce clean coal by organic acid leaching was proposed. The leaching effects of four organic acids were compared, the leaching mechanism of citric acid was analyzed, and the removal behavior of AAEMs and ash was investigated. The results show the effect of citric acid is better than others. During the leaching process, the citric acid ionizes H+, which reacts with inorganic minerals of AAEMs, completes ion exchange with AAEMs Organics. Under the relative optimized experimental conditions, the content of Na2O in coal ash is 0.9%, which is in line with the standard of power coal in China. The removal efficiency of alkaline earth metals Ca and Mg are significantly lower than those of alkali metals Na and K. The trend in the removal efficiency of Ca and ash are consistent. Citric acid leaching is an effective and promising method to produce clean coal from low-rank coal. [ABSTRACT FROM AUTHOR]

The paper analyzes the relationships among acid–base interactions in various oxide systems and their thermodynamics. Extensive data on enthalpies of solution of binary oxides in oxide melts of several compositions, obtained by high-temperature oxide melt solution calorimetry at 700 and 800 °C, are systematized and analyzed. Oxides with low electronegativity, namely the alkali and alkaline earth oxides, which are strong oxide ion donors, show enthalpies of solution that have negative values greater than −100 kJ per mole of oxide ion. Their enthalpies of solution become more negative with decreasing electronegativity in the order Li, Na, K and Mg, Ca, Sr, Ba in both of the commonly used molten oxide calorimetric solvents: sodium molybdate and lead borate. Oxides with high electronegativity, including P2O5, SiO2, GeO2, and other acidic oxides, dissolve more exothermically in the less acidic solvent (lead borate). The remaining oxides, with intermediate electronegativity (amphoteric oxides) have enthalpies of solution of between +50 and −100 kJ/mol, with many close to zero. More limited data for the enthalpies of solution of oxides in multicomponent aluminosilicate melts at higher temperature are also discussed. Overall, the ionic model combined with the Lux–Flood description of acid–base reactions provide a consistent and useful interpretation of the data and their application for understanding the thermodynamic stability of ternary oxide systems in solid and liquid states. [ABSTRACT FROM AUTHOR]

The present article is focused on extraction alumina from high alumina fly ash using an improved hydro-chemical method with high-efficiency alkali circulation and mild reaction conditions. The alumina leaching behavior and corresponding reaction mechanism of the process were systematically investigated. The results revealed that the alumina extraction efficiency reached 50.7% in the low alkali process with alkali concentration of C(Na2O) = 230 g/L, and the total alumina extraction ratio reached 92.4% in the high alkali process with alkali concentration of C(Na2O) = 380 g/L. The presence of Ca leads to the formation of katoite (Ca2.93Al1.97Si0.64O2.56(OH)9.44) during the low alkali process, which reduces the alumina extraction rate. Isomorphism occurs in the high alkali process and generates iron-containing hydrated garnet (Ca3(Fe0.87Al0.13)2(SiO4)1.65(OH)5.4), which improves the alumina extraction rate, The improved hydro-chemical process proposed in this paper not only has milder reaction conditions, but also the cycle efficiency is > 330% higher compared with the hydro-chemical method of the existing literature. [ABSTRACT FROM AUTHOR]

Dongcao muscovite granite, as the product of the second stage of the magmatic intrusion of the Ganfang composite pluton, is closely related to the mineralization of Li–Nb–Ta rare metals in the Yifeng area. This paper aims to discuss the diagenetic age, evolutionary process, and relationship with the rare metal mineralization of Dongcao muscovite granite by using petrographic, cassiterite U–Pb dating and geochemical analyses. Petrographic analysis shows that the lithology of the Dongcao muscovite granite is medium– to fine–grained muscovite monzogranite. The cassiterite U–Pb dating results show that the diagenetic age of the Dongcao muscovite granite is 139.7 ± 6.7 Ma, which is Early Cretaceous. The geochemical analysis indicates that the rock is characterized by high Si, abundant aluminum alkalis, low Ca and Fe, and low Mg, which indicates that this granite is a strongly peraluminous rock. Moreover, the Dongcao muscovite granite is enriched with Rb, U, Ta, Pb, P, and Hf and depleted of Ba, Sr, Ti, and rare earth elements (REEs), with a tetrad effect of REEs. Based on this analysis, the Dongcao muscovite granite is a highly differentiated granite that formed in the tectonic transition from continental collisional to post–collisional settings related to the subduction of the Paleo–Pacific plate. A high degree of crystallization differentiation occurred at the early stage of magmatic evolution, resulting in the initial enrichment of Li–Nb–Ta–Sn. The melt–fluid interaction in the late stage is significant to the high enrichment of Li–Nb–Ta–Sn until the final mineralization. [ABSTRACT FROM AUTHOR]

In recent years, with the further study of rare earth halide scintillation crystals, many excellent properties of these materials have been discovered, especially the neutron/gamma ray dual detection performance, which has attracted much attention. Ce doped lithium based elpasolite scintillation crystal with chemical composition of A2LiRX6: Ce (A, R, X represent + 1 valence metal element, rare earth element, halogen element respectively) and Eu doped lithium based alkaline earth metal halide with chemical composition of LiM2X5: Eu (M, X represent + 2 valence metal element, halogen element respectively) are considered to be very practical and potential dual detection materials. They can detect neutrons and gamma rays simultaneously, and most of them have high light output, excellent energy resolution and other characteristics. At present, as the most representative of Ce doped lithium based elpasolite scintillation crystal, Cs2LiYCl6:Ce (CLYC) has been widely studied and produced. However, Eu doped lithium based alkaline earth metal halide, which is expected to replace elpasolite scintillation crystal materials such as CLYC, is rarely reported. In this paper, the research progress of the above two kinds of dual-mode detection materials is briefly reviewed, with a view to enlightening researchers in related fields. [ABSTRACT FROM AUTHOR]

Activation of dinitrogen (N2) is the critical step in nitrogen reduction reaction (NRR) in ammonia synthesis. In this paper, reaction mechanisms of N2 activation on trimetallic clusters Mo2M (M = Li, Na, K, Mg, and Ca) and Mo3−xCax (x = 2–3) were systematically studied by density functional theory calculations. Unlike Mo2 which is inert to N2, clusters with alkali or alkaline earth metal atoms have much higher reactivity toward N2 in terms of both thermodynamics and kinetics. Particularly, in one reaction path of N2 with MoCa2, all the intermediates and transition states are well below the energy sum of the reactants, indicating that the dissociation of N2 on MoCa2 can take place spontaneously in gas-phase reactions. N2 transfers on clusters with different coordination modes, and the N−N bond is gradually activated. When N2 is bonded with three metal atoms with end-on: side-on: side-on coordination mode, it is fully activated and easily dissociated into two adsorbed N atoms. These results may serve as a prototype to design single-cluster catalysts with a trimetallic center for nitrogen activation and conversion. [ABSTRACT FROM AUTHOR]

In this paper, a method for dealkalization and upgrading of high alkali coal by supercritical CO2 fluid-citric acid extraction system is proposed. The leaching mechanism was explored by microstructural changes of elements and functional groups in coal samples, and single-factor optimization experiment was conducted. The result shows that supercritical CO2 fluid-citric acid extraction can effectively remove alkali and alkaline earth metals. The extraction mechanism is the reaction of H+ with inorganic minerals and the ion exchange of H+ with the form of phenolic hydroxyl and carboxyl groups. Under the optimum conditions, the removal rates of Ca and Mg are 44.95% and 65.75% respectively. The ash content of coal is 2.42%, and the content of Na2O (calculated by ash) is 1.13%, which meet the standards of power coal in China. Supercritical CO2 fluid-citric acid extraction is an effective and promising method for the cleaning of high alkali coal. [ABSTRACT FROM AUTHOR]

The Qushandao Granite, mainly composed of alkali‐feldspar granite, is situated in the eastern Zhejiang province of coastal southeast China. In this paper, we present whole‐rock geochemistry, zircon U–Pb geochronology, and Hf isotopes to constrain the age, magma sources, and geodynamic setting of the Qushandao Granite. LA‐ICP‐MS zircon U–Pb dating results revealed that the Qushandao Granite was emplaced in the Late Cretaceous (101–98 Ma). Geochemically, the Qushandao Granite exhibits relatively high silica and alkali contents, metaluminous to weakly peraluminous (A/CNK = 0.98–1.02), and low abundances of phosphorus, titanium, magnesium, and calcium. It is also characterized by enrichment in Rb, K, Th, and depletion in Nb, Ta, P, Ti, and Sr with moderately to weakly negative europium anomalies (Eu/Eu* = 0.71–0.87). Furthermore, the Qushandao Granite displays lower FeOT/MgO, 104 × Ga/Al, and Zr + Nb + Ce + Y values relative to typical A‐type granites. Therefore, we classify the Qushandao Granite as calc‐alkaline I‐type granite based on a synthesis of geological and geochemical characteristics. The Qushandao Granite shows variable zircon Hf isotopic compositions (εHf(t) = −7.6 to +2.3) and TDM2 model ages of 1.40–0.83 Ga with a mean value of 1.17 Ga. We argue that the Qushandao Granite was most likely generated by mixing of mantle‐derived mafic magma and crust‐derived felsic magma in the lower crust, and that it was formed during post‐collisional extension in the Late Cretaceous, related to the gradually increasing subduction angle of the Paleo‐Pacific plate. [ABSTRACT FROM AUTHOR]

This article was originally published online on 29 August 2022 with errors in the first and fourth affiliations. Footnotes 1 Note: This paper is part of the JCP Special Topic on Nature of the Chemical Bond. I. The alkaline earth metals Be, Mg, and Ca" [J. Chem. Phys. [Extracted from the article]