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We performed high-level ab initio quantum chemical calculations, incorporating higher-order excitations, spin–orbit coupling (SOC), and the Gaunt interaction, to calculate the electron affinities (EAs) of alkaline earth (AE) metal atoms (Ca, Sr, Ba, and Ra), which are notably small. The coupled-cluster singles and doubles with perturbative triples [CCSD(T)] method is insufficient to accurately calculate the EAs of AE metal atoms. Higher-order excitations proved crucial, with the coupled-cluster singles, doubles, and triples with perturbative quadruples [CCSDT(2)Q] method effectively capturing dynamic electron correlation effects. The contributions of SOC (ΔESOs) to the EAs calculated using the multireference configuration interaction method with the Davidson correction, including SOC, positively enhance the EAs; however, these contributions are overestimated. The Dirac–Hartree–Fock (DHF)-CCSD(T) method addresses this overestimation and provides reasonable values for ΔESO (ΔESO−D). Employing additional sets of diffuse and core–valence correlation basis sets is critical for accurately calculating the EAs of AE metal atoms. The contributions of the Gaunt interaction (ΔEGaunt) to the EAs of AE metal atoms are negligible. Notably, the CCSDT(2)Q with the complete basis set limit + ΔESO−D + ΔEGaunt produced EA values for Ca, Sr, and Ba that closely aligned with experimental data and achieved accuracy exceeding the chemical accuracy. Based on our findings, the accurately proposed EA for Ra is 9.88 kJ/mol. [ABSTRACT FROM AUTHOR]

Hydrated cation–π interactions at liquid–solid interfaces between hydrated cations and aromatic ring structures of carbon-based materials are pivotal in many material, biological, and chemical processes, and water serves as a crucial mediator in these interactions. However, a full understanding of the hydrated cation–π interactions between hydrated alkaline earth cations and aromatic ring structures, such as graphene remains elusive. Here, we present a molecular picture of hydrated cation–π interactions for Mg2+ and Ca2+ by using the density functional theory methods. Theoretical results show that the graphene sheet can distort the hydration shell of the hydrated Ca2+ to interact with Ca2+ directly, which is water–cation–π interactions. In contrast, the hydration shell of the hydrated Mg2+ is quite stable and the graphene sheet interacts with Mg2+ indirectly, mediated by water molecules, which is the cation–water–π interactions. These results lead to the anomalous order of adsorption energies for these alkaline earth cations, with hydrated Mg2+–π < hydrated Ca2+–π when the number of water molecules is large (n ≥ 6), contrary to the order observed for cation–π interactions in the absence of water molecules (n = 0). The behavior of hydrated alkaline earth cations adsorbed on a graphene surface is mainly attributed to the competition between the cation–π interactions and hydration effects. These findings provide valuable details of the structures and the adsorption energy of hydrated alkaline earth cations adsorbed onto the graphene surface. [ABSTRACT FROM AUTHOR]

The chemical flexibility of metal-organic frameworks (MOFs) offers an ideal platform to tune structure and composition for specific applications, from gas sensing to catalysis and from photoelectric conversion to energy storage. This variability gives rise to a large configurational space that can be efficiently explored using high-throughput computational methods. In this work, we investigate from first principles the structural and electronic properties of MOF-5 variants obtained by replacing Zn with Be, Mg, Cd, Ca, Sr, and Ba and by functionalizing the originally H-passivated linkers with CH3, NO2, Cl, Br, NH2, OH, and COOH groups. To build and analyze the resulting 56 structures, we employ density-functional theory calculations embedded in an in-house developed library for automatized calculations. Our findings reveal that structural properties are mainly defined by metal atoms and large functional groups, which distort the lattice and modify coordination. The formation energy is largely influenced by functionalization and enhanced by COOH and OH groups, which promote the formation of hydrogen bonds. The charge distribution within the linker is especially influenced by functional groups with electron-withdrawing properties, while the metal nodes play a minor role. Likewise, the bandgap size is crucially determined by ligand functionalization. The smallest gaps are found with NH2 and OH groups, which introduce localized orbitals at the top of the valence band. This characteristic makes these functionalizations particularly promising for the design of MOF-5 variants with enhanced gas uptake and sensing properties. [ABSTRACT FROM AUTHOR]

The functional properties of piezoelectric ceramic materials, such as barium titanate, are highly dependent on grain size. Lead-free polycrystalline Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) samples were prepared with a combination of the hydrothermal method and spark plasma sintering to achieve grain sizes from 100 nm to 10 μm by varying the maximum sintering temperature. In this range, a transition from a nearly linear dielectric to a ferroelectric response can be seen in macroscopic electromechanical measurements, demonstrating the importance of grain size on functional properties in BCZT. Furthermore, in situ electric field-dependent synchrotron x-ray diffraction measurements were performed to quantify the intrinsic and extrinsic strain contributions and their variations with grain size. At lower grain sizes, the data revealed a significant loss of extrinsic contributions in the piezoelectric behavior, limiting the response to intrinsic contribution associated with lattice strain. For BCZT, a critical grain size between approximately 0.08 and 0.18 μm is proposed, below which no piezoelectric response was observed. [ABSTRACT FROM AUTHOR]

Piezoceramics with the formula Pb0.93Sr0.06Ba0.01(Mg1/3Nb2/3)0.035(Ni1/3Nb2/3)0.2 (Sb1/2Nb1/2)0.015(ZrxTi1−x)0.75O3 + 0.5 wt. % Li2CO3, where x = 0.51, 0.50, 0.49, 0.48, 0.47, and 0.46, have been made using the one-step solid-state method. The phase structure and electrical properties were systematically investigated in the quinary system. Here, the crystalline structure transformed gradually from the rhombohedral to tetragonal phase with decreasing Zr content. More importantly, the effective piezoelectric coefficient d33* of the ceramics demonstrates an excellent thermal stability below the Curie temperature. Meanwhile, piezoelectric ceramics with x = 0.49 exhibited the extraordinary electrical properties near the morphotropic phase boundary. A huge piezoelectric coefficient d33 = 853 pC/N, high Curie temperature TC = 152 °C, and the electromechanical coupling coefficients kp = 67.4%, kt = 63.5%, and k33 = 67.4% were obtained at the composition of x = 0.49, which may lead a promising future for the transducer applications. [ABSTRACT FROM AUTHOR]

Frustrated lattices with dispersionless band structures and fully localized states are an exciting platform for exploring many-body physics. In this work, we identify X 3 MnN 3 (X = Ca, Sr, Ba) as a frustrated lattice and investigate its physical properties in the ferromagnetic (FM) and antiferromagnetic (AFM) states based on first-principles calculations. Our results show that all three materials in FM and A-type AFM configurations have flatbands with band touching in the k z ∼ 0 and k z ∼ π planes with bandwidths less than 0.2 eV. Intriguingly, the flatband is tuned to the Fermi level when X 3 MnN 3 is transformed into the FM state. Furthermore, we find the two-dimensional dice model hidden in X 3 MnN 3 by treating the coupled Mn and N atoms as a basic site, revealing that the compact localized state is generated by destructive interferences between the hopping amplitudes, and the dice models stack the system staggered along the c -axis. Our work provides new candidate materials for exploring strong correlation physics and reveals the mechanism of their localized state. [ABSTRACT FROM AUTHOR]

Machine learning interatomic potentials have emerged as a powerful tool for bypassing the spatiotemporal limitations of ab initio simulations, but major challenges remain in their efficient parameterization. We present AL4GAP, an ensemble active learning software workflow for generating multicomposition Gaussian approximation potentials (GAP) for arbitrary molten salt mixtures. The workflow capabilities include: (1) setting up user-defined combinatorial chemical spaces of charge neutral mixtures of arbitrary molten mixtures spanning 11 cations (Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba and two heavy species, Nd, and Th) and 4 anions (F, Cl, Br, and I), (2) configurational sampling using low-cost empirical parameterizations, (3) active learning for down-selecting configurational samples for single point density functional theory calculations at the level of Strongly Constrained and Appropriately Normed (SCAN) exchange-correlation functional, and (4) Bayesian optimization for hyperparameter tuning of two-body and many-body GAP models. We apply the AL4GAP workflow to showcase high throughput generation of five independent GAP models for multicomposition binary-mixture melts, each of increasing complexity with respect to charge valency and electronic structure, namely: LiCl–KCl, NaCl–CaCl2, KCl–NdCl3, CaCl2–NdCl3, and KCl–ThCl4. Our results indicate that GAP models can accurately predict structure for diverse molten salt mixture with density functional theory (DFT)-SCAN accuracy, capturing the intermediate range ordering characteristic of the multivalent cationic melts. [ABSTRACT FROM AUTHOR]

Textured BaTiO 3 -based piezoelectric ceramics show the excellent application potential as their piezoelectric characteristics almost approach the commercial lead-based ceramics. Piezoelectric multilayer actuators (MLAs) with low driving voltages and compact structures are great in line with the equipment trend of miniaturization and functional integration. However, the coarse textured grains result in few grain layers in each thin ceramic layer of MLAs, hardly guaranteeing the electromechanical dependability. In this work, we combined the composition regulation with a modified template grain growth (TGG) to prepare fine-grained textured ceramics. The Zr4+ and Sn4+ co-substituted (Ba 0.95 Ca 0.05)(Ti 0.94 Zr 0.05 Sn 0.01)O 3 (BCZTS) was chosen as the matrix composition. Unreacted BaCO 3 (BC, 7.3 % in content) was artificially introduced into matrix to realize the partial reaction template grain growth (RTGG), reducing textured grains from 9.7 μm to 6.9 μm. Textured BCTZS-BC MLAs achieved high texture degree of 92 % and further smaller grain size of 3.4 μm at 1300 °C, due to inhibition on mass transfer and improvement on thermal conductivity of Pt electrodes. The high strain of 0.12 % in textured MLAs is almost 2.3 times enhancement compared to non-textured counterparts, and the ultralow strain hysteresis H s of 5.6 % at 30 kV/cm is equivalent to that in PZT MLAs. The microscopic coercive voltage is 3.1 V with a maximum displacement of 210 p.m., which is mainly ascribed to the smaller domain sizes and the favorable "4O" domain configuration in textured MLAs. [ABSTRACT FROM AUTHOR]

This article provides a comprehensive review of various methods for synthesizing silyl anions, which are important in synthetic organic chemistry. The article discusses different approaches for generating silylboranes, silylaluminum compounds, and disilanes. It highlights the challenges and limitations of each method and presents recent advancements in the field. The authors emphasize the need for further development and improvement in the synthesis of silyl anions to enhance their properties and expand their applications in organic chemistry. The article is written by a group of researchers who have expertise in the field and provides valuable insights for library patrons conducting research on silyl anions. [Extracted from the article]

This study investigates the effects of low-level Sr2+ substitutions on the microstructures and electrical properties of BSZT ceramics with formula (Ba 1- x Sr x)(Zr 0·025 Ti 0.975)O 3. The ability of BSZT ceramics to convert energy is assessed based on the piezoelectric coefficient, d 33 associated with the figure of merit (FOM). BSZT ceramics with 0.00 ≤ x ≤ 0.10 were sintered at 1350 °C for 2 h. The XRD measurement confirmed the formation of a single-crystalline phase in all ceramics. All ceramics stabilized in tetragonal crystal structures with progressive decline in tetragonality. It was found that the ceramic with low-level Sr2+ substitutions demonstrated excellent dielectric, piezoelectric and ferroelectric behaviours before gradually deteriorated at higher contents. Systematic deviation of Sr2+ atomic percentage signified broad dielectric curves compared to pristine Ba(Zr 0·025 Ti 0.975)O 3. A significant increase of remnant polarization, P r value (11.21 ± 0.12 μC/cm2) was recorded when x = 0.02, in line with its highest as-sintered density and tetragonality. High d 33 and low ε 33 values contributed to an optimum value of piezoelectric voltage, g 33 coefficient. Consequently, a high FOM comparable to PZT was obtained. The current work successfully demonstrated the preparation of lead-free ceramics based on BaTiO 3 with great potential for energy conversion applications. [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]

Amorphous Li 3 PS 4 , Li 2.94 Mn 0.06/n PS 4 (M = Mg, Ca, Al) and Li 2.94 Ca 0.03 PS 3.94 Xy 0.06/y (X = N, I) solid electrolytes were successfully prepared by planetary ball-milling method. Their structure was investigated using XRD and Raman spectroscopy. The data obtained from complex impedance spectroscopy was analyzed to study the ionic conductivity and relaxation dynamics in the prepared samples. The data was interpreted using conductivity isotherms, electrical modulus and dielectric loss tangent. Among the samples, Li 2.94 Al 0.02 PS 4 exhibited highest ionic conductivity at 25 °C, which was about 6.6 x 10−4 Scm−1. Electrical modulus and dielectric loss tangent analysis suggested that grain boundary polarization and ionic conductivity increased with multivalence cation doping. [ABSTRACT FROM AUTHOR]

Owing to the intrinsic chemical disorder of microscopic composition, perovskite high‐entropy ceramics exhibit dielectric relaxation behaviors and are favorable for energy storage performance. In this work, (Bi0.2Na0.2Ca0.2Ba0.2Sr0.2)(Ti1−xNbx)O3 (BNCBST‐xNb, 0.01 ≤ x ≤ 0.25) ceramics were prepared using a hydrothermal method. The results indicate that Nb doping into BNCBST induces lattice expansion and deepens dielectric relaxation. Moreover, the BNCBST‐xNb ceramics exhibit a great enhancement of electrical breakdown strength (Eb) with Nb content, which results from the reduction of grain size, the increase of resistivity, the decrease of oxygen vacancies, and the enlargement of band gap width. Consequently, the BNCBST‐0.15Nb system presents an outstanding Eb of 497 kV/cm with excellent recoverable energy density (Wrec = 3.85 J/cm3) and efficiency (η = 87.7%), accompanying by the wide temperature stability (Wrec and η vary within ± 9.8% and ± 1.4% at 40–100°C) and fast discharge rate (t0.9 = 88 ns). The significant improvement of Eb and energy storage properties suggest that our research offers an effective strategy for developing lead‐free energy storage ceramics. [ABSTRACT FROM AUTHOR]

Permian alkaline granitoids are widely distributed throughout the Tien Shan Orogen and adjacent region of the southern Central Asian Orogenic Belt. However, their petrogenesis and related tectonic setting remain equivocal. A detailed mineralogical, U-Pb zircon dating, in situ elemental and Sr-Nd-Hf isotopic studies of the uranium-rich Akkulen syenite intrusion in the Northern Tien Shan of Kyrgyzstan were undertaken to better understand its magmatic processes and geodynamic evolution. Four independent oxygen barometers have shown that the oxygen fugacity of the Akkulen syenitic magma evolved from initial low fO2 (NNO +1) during magma ascent and cooling; Apatite geochemical characteristics also indicate that the magma is relatively high F (2.9–5.1 wt.%), with low Cl (0.053–0.13 wt.%) and anhydrous (<4 wt %) contents. According to whole-rock geochemical data, the syenite samples have abnormally high U (38.5–57.1 ppm) and Th (96.2–137 ppm) concentrations, we suggest that high F content and moderate oxygen fugacity are beneficial for uranium enrichment. Zircon grains from a syenite sample yielded a weighted 206Pb/238U age of 283.5 ± 2.6 Ma. The intrusion has an A-type granite affinity with high alkali (Na2O + K2O) contents and Fe/(Fe+Mg) ratios, high LREE/HREE (~5), and low Sr, Ba, and Eu contents. They have negative εNd(t) (−5.2 to −3.6) values with Mesoproterozoic two-stage model ages (T DM2 = 1.35–1.47 Ga), and variable εHf(t) values (−4.6 to +2.4) with Mesoproterozoic two-stage model ages (T DM2 = 1. 2–1.59 Ga), which suggest these rock derivations from the relatively old crustal with minor contribution from juvenile crustal melts. In comparison with regional available dataset, we propose that the alkaline Permian granitoids in Kyrgyz Northern Tien Shan may have been originated from large-scale partial melting of Mesoproterozoic metamorphic basement with minor juvenile crustal material in a post-extensional setting. In contrast, the Early Permian granitoid magmatism in the Tarim Craton may have been caused by the partial melting of Neoproterozoic basement rocks associated with Permian mantle plume activities. [ABSTRACT FROM AUTHOR]

Heteroleptic, bimetallic (Mg/K) cyclopentadienyl complexes (2–4) were synthesized by the reaction of the Mg–Mg-bonded compound [K(THF)3]2[LMg–MgL] (1, L = [(2,6-iPr2C6H3)NC(CH3)]22−) with cyclopentadiene derivatives, 6,6-dimethylfulvene, 6-(dimethylamino)fulvene, or 1,2,3,4-tetramethyl-1,3-cyclopentadiene. The reactions proceed through diverse pathways, including hydrogen abstraction, C–C coupling, and dehydrogenation, depending on the property of the polyene substrate, thus providing an access to alkali/alkaline earth metal cyclopentadienyl complexes. [ABSTRACT FROM AUTHOR]

The oxidative coupling of methane (OCM) provides a direct route to transform methane into higher value products. The alkali metal tungstate catalysts have demonstrated high selectivity towards C2 products, ethane (C2H6) and ethylene (C2H4). However, the severe sintering of the SiO2 support limits the reaction rate requiring active site densification to compete with unselective gas phase combustion reaction especially at high pressure operations. This work studies alkaline earth metal oxides as supports for K2WO4 catalysts to maintain comparatively high surface area under OCM conditions. Among Mg, Ca, and Sr aluminates, the K2WO4/MgAl2O4 catalyst exhibited the highest C2 yields. To achieve high C2 product selectivity, a relatively large loading of K2WO4 (20 wt %) was required likely to cover the unselective surface sites of MgAl2O4 support. The catalyst further showed high levels of stability when utilized at high pressures (0.9 MPa) for over 60 h, without any change in product selectivity. The Mn/K2WO4/MgAl2O4 showed multifold higher CH4 conversion rate, compared with the SiO2 counterpart. The findings showcase the potential of the MgAl2O4 support as a viable candidate for alkali metal tungstate catalysts for OCM, which introduces high density of active components in given volume in the reactor, which induces high contribution of the catalyst relative to the pure gas phase oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Incineration bottom ash (IBA) was good support for Ni in catalytic toluene reforming. • An activation stage was observed for Ni/IBA because of the metal-support interaction. • Formation of Ni-FeO x improves the redox ability and is responsible for activation. • Resistance to coking is due to the FeO x and alkali and alkaline earth metals in IBA. The incineration bottom ash (IBA) was impregnated with nickel to catalyze toluene (tar surrogate) steam reforming. A toluene conversion of >80 % was achieved at 800℃ without activity decay in a 100-h test for 15 %Ni/IBA. An activation stage was observed for Ni/IBA catalysts in the initial 50 ∼ 400 min under different reaction conditions. A series of experiments and characterizations were performed to explore the possible mechanisms for the activation. It was found that the iron species in IBA gradually migrated to the catalyst surface and formed a Ni-FeO x complex owing to the metal-support interaction. The synergy of Ni-FeO x played an important role in improving the activity of Ni/IBA due to the enhanced lattice oxygen activity. Additionally, Ni/IBA catalysts showed a much lower coke deposition rate than Ni/Al 2 O 3 (1.12 vs. 3.45 mg-C/g cat ∙h) because of the variable states of FeO x and the abundant basic sites caused by the alkali and alkaline earth metals contained in IBA. [ABSTRACT FROM AUTHOR]

Quantum chemical calculations using ab initio methods at the MRCI+Q(8,9)/def2‐QZVPPD and CCSD(T)/def2‐QZVPPD levels as well as using density functional theory are reported for the diatomic molecules AeN− (Ae=Ca, Sr, Ba). The anions CaN− and SrN− have electronic triplet (3Π) ground states with nearly identical bond dissociation energies De ~57 kcal/mol calculated at the MRCI+Q(8,9)/def2‐QZVPPD level. In contrast, the heavier homologue BaN− has a singlet (1Σ+) ground state, which is only 1.1 kcal/mol below the triplet (3Σ−) state. The computed bond dissociation energy of (1Σ+) BaN− is 68.4 kcal/mol. The calculations at the CCSD(T)‐full/def2‐QZVPPD and BP86‐D3(BJ)/def2‐QZVPPD levels are in reasonable agreement with the MRCI+Q(8,9)/def2‐QZVPPD data, except for the singlet (1Σ+) state, which has a large multireference character. The calculated atomic partial charges given by the CM5, Voronoi and Hirshfeld methods suggest small to medium‐sized Ae←N− charge donation for most electronic states. In contrast, the NBO method predicts for all species medium to large Ae→N− electronic charge donation, which is due to the neglect of the (n)p AOs of Ae atoms as genuine valence orbitals. Neither the bond orders nor the bond lengths correlate with the bond dissociation energies. The EDA−NOCV calculations show that the heavier alkaline earth atoms Ca, Sr, Ba use their (n)s and (n‐1)d orbitals for covalent bonding. [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]

The document is the contents list for the journal "Chemical Communications" published on June 7, 2024. It includes articles on various topics such as the rational design and biomedical application of BODIPY-based photocages, synthesis and applications of porous protein crystals, and the construction of stable radical hydrogen-bonded metal-organic frameworks. The journal is published by The Royal Society of Chemistry, a leading chemistry community that connects the world with the chemical sciences. [Extracted from the article]

Nickel carbonite complexes supported by alkaline earth metals have been accessed via salt-metathesis of the corresponding alkali metal precursors. The new complexes undergo Schlenk-like exchange reactions in solution which have been investigated by NMR spectroscopy. Also their reactivity towards epoxides and carbon monoxide was studied. [ABSTRACT FROM AUTHOR]

Rare earth doped luminescent sensing materials as non-contact thermometers have attracted extensive research interests due to their wide applications in areas like military, medical care, aerospace, etc. How to expand the working temperature range and improve the sensitivity has become the focus. In this work, we synthesized a series of apatite-structured luminescent temperature sensors M 2 La 7.9 Ce 0.1 (SiO 4) 6 O 2 (M = Ca, Sr, Ba) via isomorphic substitution. By monitoring the differential changes of emission intensities from Ce3+ at the 7-coordinate and 9-coordinate site respectively when temperature varies, the real-time temperature can be determined. These materials were proven to possess the maximum absolute sensitivity up to 0.825 × 10−3 K−1, 2.63 × 10−3 K−1 and 4.33 × 10−3 K−1, respectively. Meanwhile interesting regular patterns were observed for their temperature sensitivities with the substitution of Ca, Sr and Ba. Furthermore, through studying the temperature sensitivity of Ba 2 La 8 (SiO 4) 6 O 2 : x Ce3+ samples with different concentrations, it was found that when the Ce3+ content was at the optimal doping concentration of 0.7, the absolute sensitivity of the sample reached 14.64 × 10−3 K−1 at 573 K. This finding has opened up a new avenue for designing fluorescent temperature sensors. Synopsis: In this work, Ce3+ were doped into a series of phosphor-structured matrices containing two cationic sites (7-coordinated Ce1 and 9-coordinated Ce2 sites) via the solid-state high-temperature method. Due to the different temperature dependencies of luminescence intensities between the two Ce3+ sites, their intensity ratio could be used for temperature calibration. [Display omitted] [ABSTRACT FROM AUTHOR]

We report the effect of configurational entropy (CE) on the electrocaloric (EC) effect of Ba x Sr y Ca z (Bi 0.5 Li 0.5) 1- x - y - z TiO 3 (BSCBLT) (0.627≤ x ≤ 0.66, 0.0716≤ y ≤ 0.1993, 0.0145≤ z ≤ 0.1758) ceramics. All samples were designed to show different CE but the same A-site cation average radius, tolerance factor and cationic size disorder. The samples with x ≤ 0.64 show ferroelectric (FE) relaxor behavior, while x ≥ 0.65 are normal FEs. x = 0.65 shows the maximum EC effects among all samples. Both maximum adiabatic temperature change (ΔT m) and CE vary almost in the same way with increasing x. The anomalous enhancement of ΔT m in x = 0.65 with relatively lower CE compared with that in x = 0.64 can be ascribed to an additional contribution of Ba concentration induced FE to relaxor FE transition in BSCBLT. Our results reveal important evidences of enhanced EC effects by CE and suggest that designing FEs or relaxor FEs with high CE might be an effective route to achieve high EC effects. [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]

Alkaline earth (AE) metal complexes have garnered significant interest in various functional fields due to their nontoxicity, low density, and low cost. However, there is a lack of systematic investigation into the structural characteristics and physical properties of AE‐metal‐organic frameworks (MOFs). In this research, we synthesized isostructural MOFs consisting of AE4(μ4‐Cl) clusters bridged by benzo‐(1,2;3,4;5,6)‐tris(thiophene‐2′‐carboxylic acid) (BTTC3−) ligands. The resulting structure forms a truncated octahedral cage denoted as [AE4(m4‐Cl)]6(BTTC)8, which further linked to a porous three‐dimensional framework. Among the investigated AE ions (Ca, Sr, and Ba), the Ca4‐MOF demonstrated good chemical stability in water compared to Sr4‐MOF and Ba4‐MOF. The N2 adsorption and solid‐state UV‐vis‐NIR absorption behaviors were evaluated for all AE4‐MOFs, showing similar trends among the different metal ions. Additionally, the proton conduction study revealed that the Ca4‐MOF exhibited ultra‐high proton conductivity, reaching 3.52×10−2 S cm−1 at 343 K and 98 % RH. Notably, the introduction of LiCl via guest exchange resulted in an improved proton conduction of up to 6.36×10−2 S cm−1 under similar conditions in the modified LiCl@Ca4‐MOF. The findings shed light on the regulation of physical properties and proton conductivity of AE‐MOFs, providing valuable insights for their potential applications in various fields. [ABSTRACT FROM AUTHOR]

Tetrahedron‐based nitrides offer a wide range of properties and applications. Highly condensed nitridophosphates are examples of nitrides that exhibit fascinating luminescence properties when doped with Eu2+, making them appealing for industrial applications. Here, we present the first nitridomagnesophosphate solid solution series Ba3−xSrx[Mg2P10N20] : Eu2+ (x=0–3), synthesized by a high‐pressure high‐temperature approach using the multianvil technique (3 GPa, 1400 °C). Starting from the binary nitrides P3N5 and Mg3N2 and the respective alkaline earth azides, we incorporate Mg into the P/N framework to increase the degree of condensation κ to 0.6, the highest observed value for alkaline earth nitridophosphates. The crystal structure was elucidated by single‐crystal X‐ray diffraction, powder X‐ray diffraction, energy‐dispersive X‐ray spectroscopy (EDX), and solid‐state NMR. DFT calculations were performed on the title compounds and other related highly condensed nitridophosphates to investigate the influence of Mg in the P/N network. Eu2+‐doped samples of the solid solution series show a tunable narrow‐band emission from cyan to green (492–515 nm), which is attributed to the preferred doping of a single crystallographic site. Experimental confirmation of this assumption was provided by overdoping experiments and STEM‐HAADF studies on the series as well on the stoichiometric compound Ba2Eu[Mg2P10N20] with additional atomic resolution energy‐dispersive X‐ray spectroscopy (EDX) mapping. [ABSTRACT FROM AUTHOR]

The sedimentary sequence of the Ninama Basin is associated with the latest phase of the continental Deccan volcanism of the Indian peninsula. It occurs as inter-, intratrappeans with a 39-m thick sequence comprising Sukhbhadar Formation and Ninama Limestone. The investigation aims to reconstruct its depositional setting based on the lithofacies and inorganic geochemistry to understand the influence of paleosalinity, paleoredox, paleodepth, provenance and paleoclimate on the sedimentation pattern. It is characterized by clastic and chemically formed rocks, including shale, mudstone, siltstone, sandstone and limestone. Facies analysis has revealed seven lithofacies, amongst which four are clastic facies, shale (SH), calcareous shale (CSH), silty mudstone (SM) and lithic greywacke (LGW), and three are carbonate facies, namely, grey-black limestone (GBL), cherty limestone (CL) and marlite (ML). Using geochemical analysis of major oxides and trace elements, ratios of Ca/(Ca+Fe), Sr/Ba, V/(V+Ni), V/Cr, Fe/(Ca+Mg), Ti/Al, Na/K, K/(Fe+Mg), CIA-K and MAP were determined and used to interpret and note the changes in the depositional system. The combined results of the lithofacies and geochemistry indicate that the deposition occurred in three phases. Phase 1 is characterized by high energy conditions in the shallow to moderate depth brackish-saline lake with oxic to dysoxic conditions; Phase 2 is characterized by anoxic deep fresh to the brackish water basin; and Phase 3 is characterized by semiarid conditions, saline, anoxic waters, high evaporation leading to shallowing of the lake, and low to moderate terrestrial input. This lacustrine basin in the paleotopographic low of the Deccan Volcanic Province is characterized by distinct lithology governed by various depositional parameters. A composite depositional model is constructed for the Ninama Basin, reflecting three phases of evolution that are dominantly controlled by the paleoenvironment. Research highlights: The present study focuses on lithofacies and inorganic geochemical analysis of Ninama paleolake sediments, Saurashtra intertrappeans, to interpret their paleosalinity, paleoredox, water depth, provenance, detrital influx, and paleoclimate. Phase 1 deposition was initiated in paleotopographic low of Deccan Traps, in an oxic–dysoxic, high-energy turbulent brackish water environment, in humid conditions. Phase 2 characterizes fine-grained clastic facies deposited in anoxic, fresh-brackish, deep lake waters in humid conditions. Phase 3 marks the shallowing, evident by carbonate facies with low-moderate terrestrial input deposited in saline and anoxic paleolake in semiarid conditions with high evaporation and low-moderate precipitation. The Deccan Traps have influenced the paleolake intertrappean sequence. [ABSTRACT FROM AUTHOR]

We have systematically investigated the critical behavior around paramagnetic-ferromagnetic (PM-FM) phase transition temperature, TC, and attempted to determine the Curie temperatures and critical exponents β, γ and δ of perovskite manganites La0.67Ba0.33–xSrxMnO3 (x = 0.1, 0.2 and 0.25).The TC determined from M(T) is observed to increase from 336.7 to 368.4 K, with Sr doping at Ba. The critical exponents β, γ and δ are determined from the magnetization, M(T,H), using Modified Arrott Plots for theoretically predicted models and critical M(H) isotherms at T = TC. From the critical exponents we have inferred that La0.67Ba0.33–xSrxMnO3 behave as a three-dimensional (3D) isotropic nearest heighbor Heisenberg ferromagnet in the critical region. We have further verified that the behavior of 3D isotropic nearest neighbor Heisenberg is in agreement with the values of exponent 'n' determined based on the relation between field dependent change in magnetic entropy at the Curie temperature, T = TC. Sr doping at Ba site in La0.67Ba0.33–xSrxMnO3 does not lead to any crossover in the type of magnetic interactions present in the materials, indicating a stable behavior of 3D isotropic nearest neighbor Heisenberg ferromagnet in the critical region. The differences in the values of parameters may be attributed to the complex nature of interactions present in these materials. [ABSTRACT FROM AUTHOR]

Alkali‐activated materials can be formed by alkali‐activation of Fe‐rich non‐ferrous metallurgical slags (AA‐NFMS). To study NFMS in AA‐NFMS systematically, five NFMS were synthesized, with different CaO (6–16 wt%), Al2O3 (7–11 wt%), and MgO (0–4 wt%) contents, while keeping the same FeOx/SiO2 molar ratio. The effect of slag chemistry and the alkali ions (Na+/K+ = 0, 0.5, and 1) in alkali‐activating solution on the reaction kinetics, compressive strength (3, 7, and 28 days), and pore structure of AA‐NFMS was investigated. The reactivity up to 3 days was evaluated via isothermal calorimetry, and the pore structure was analyzed via mercury intrusion porosimetry. Higher Al/Si in the slag showed higher reactivity, higher compressive strength, and lower total porosity of the AA‐NFMS. Higher Ca/Si yielded lower cumulative heat after 3 days and decreased early compressive strength but higher strength after 28 days of curing. Ca replacement by Mg led to faster reaction kinetics but inferior mechanical properties and increased porosity. Increased K+ concentration in the activator resulted in higher reactivity and compressive strength despite the higher total porosity. Empirical model fitting using JMP software revealed that K+/(N++ K+) in the activator, Ca/Si, and (Ca+Mg)/Si in NFMS are significant factors that affect the strength of AA‐NFMS. [ABSTRACT FROM AUTHOR]

The effect of Ca2+ − doping on the electrical conductivity of the oxide BaLa2In2O7 with Ruddlesden-Popper structure was investigated for the first time. The BaCaxLa2-xIn2O7-0.5× solid solution exists in the composition range of 0 ≤ x ≤ 0.10. The electrical conductivity of the BaCaxLa2-xIn2O7-0.5× ceramic samples was measured as a function of temperature (T), oxygen partial pressure (pO2), and water vapor partial pressure (pH2O). The introduction of Ca2+ into the crystal lattice led to an increase in oxygen-ion conductivity by 0.25 orders of magnitude at 500 °C, which is attributed to the formation of oxygen vacancies. The share of oxygen-ion transport increased from 23 to 80% with decreasing temperature from 900 to 425 °C, compared to 20% for the undoped phase for the same temperature range. The increase in pH2O increases the proton concentration in the structure, which is confirmed by the growth of conductivity and the reduction in activation energy. The activation energy of proton conduction increases with increasing x due to additional contribution of the proton «trapping» energies ΔEH. The doped BaCaxLa2-xIn2O7-0.5× samples are nearly pure protonic conductors below 600 °C, but undoped sample exhibits predominant proton transport below 300 °C. The electrical properties of BaMxLa2-xIn2O7-0.5x (M = Ca2+, Sr2+, and Ba2+) were compared. [ABSTRACT FROM AUTHOR]

This study explores the use of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) membranes for pure hydrogen production via water splitting. The membrane was coated with a BaCe0.2Fe0.8O3-δ catalyst to activate the water splitting reaction in a membrane reactor. H2O/Ar and CH4/Ar gas mixtures were supplied to the feed and sweep sides, respectively. Exit gases were analysed in situ using micro-GC. The results revealed that the hydrogen production rate increased with increasing temperature, methane, and water concentrations. The highest hydrogen production rate (0.37 µmol/cm2s) was achieved at 925 °C using 15% CH4 in the sweep and 55% H2O in the feed. On the sweep side, CH4 reacts to generate CO2 and syngas (H2 + CO) in a ratio commonly used in integrated gasification combined cycle power plants. This study highlights the potential of BSCF membranes as a promising technology for simultaneous production of pure hydrogen, on one side, and syngas through controlled reactions involving methane and permeated oxygen, on the other side. [ABSTRACT FROM AUTHOR]

Oxidative dehydrogenation (ODH) of light alkanes to produce C2−C3 olefins is a promising alternative to conventional steam cracking. Perovskite oxides are emerging as efficient catalysts for this process due to their unique properties such as high oxygen storage capacity (OSC), reversible redox behavior, and tunability. Here, we explore AFeO3 (A=Ba, Sr) bulk perovskites for the ODH of ethane and propane under chemical looping conditions (CL‐ODH). The higher OSC and oxygen mobility of SrFeO3 perovskite contributed to its higher activity but lower olefin selectivity than its Ba counterpart. However, SrFeO3 perovskite is superior in terms of cyclic stability over multiple redox cycles. Transformations of the perovskite to reduced phases including brownmillerite A2Fe2O5 were identified by X‐ray diffraction (XRD) as a cause of performance degradation, which was fully reversible upon air regeneration. A pre‐desorption step was utilized to selectively tune the amount of lattice oxygen as a function of temperature and dwell time to enhance olefin selectivity while suppressing CO2 formation from the deep oxidation of propane. Overall, SrFeO3 exhibits promising potential for the CL‐ODH of light alkanes, and optimization through surface and structural modifications may further engineer well‐regulated lattice oxygen for maximizing olefin yield. [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]

The magma sources, origins and precise forming ages of the miarolite from Qishan and Kuiqi intrusions are still uncertain. New results reveal that, miarolites from the Qishan and Kuiqi intrusions yield crystallization ages of ∼101 and ∼98 Ma, and they have a high formation temperature (∼910°C) and low oxygen fugacity value, indicating crystallization condition at low pressure in the upper crust with temperature of 678°C. The Qishan and Kuiqi miarolites are characterized by enrichment in SiO2 and high‐K alkali, depletion in Ca and Mg, and belong to the high‐K weak peraluminous rock series. The samples are enriched in HFSEs (i.e., Ta, Zr and Hf) and LILEs (i.e., Ba, P and Sr), depleted in Ba and Sr with the negative anomaly of Eu. In the primitive mantle normalized trace element spider diagram, the samples show a right‐inclined 'seagull‐type' pattern, combined the ratios of (La/Yb)N, 10000 × Al/Ga, Rb/Nb and Nb/Ta etc., they were proved to be alkaline A‐type granite. Combined the characterize of the trace elements, they were derived from clay‐rich source accompanied pelite melting, and subjected to K‐feldspar crystallization fractional. The values of εHf(t) and tDM2 are distributed in the range of –2.8 to 3.3 with ∼1.2 Ga, and –6.0 to 4.0 with ∼1.2 Ga, revealing that they were generated from the Mesoproterozoic Cathaysia basement rocks. The comprehensive research reveals the Kuiqi and Qishan intrusions derived from crust‐mantle mixing and partial melting of the crust, respectively, resulting from lithospheric extension generated by the Paleo‐Pacific Plate subducted into the European–Asian Plate. [ABSTRACT FROM AUTHOR]

The only occurrence of Lower Triassic silicic volcanic rocks within the South China Block is in the Qinzhou Bay area of Guangxi Province. LA‐ICP‐MS zircon U‐Pb dating reveals that volcanic rocks of the Beisi and Banba formations formed between 248.8 ± 1.6 and 246.5 ± 1.3 Ma, coeval with peraluminous granites of the Qinzhou Bay Granitic Complex. The studied rhyolites and dacites are characterized by high SiO2, K2O, and Al2O3, and low MgO, CaO, and P2O5 contents and are classified as high‐K calc‐alkaline S‐type rocks, with A/CNK = 0.98–1.19. The volcanic rocks are depleted in high field strength elements, e.g., Nb, Ta, Ti, and P, and enriched in large ion lithophile elements, e.g., Rb, K, Sr, and Ba. Although the analyzed volcanic rocks have extremely enriched zircon Hf isotopic compositions (εHf(t) = –29.1 to –6.9), source discrimination indicators and high calculated Ti‐in‐zircon temperatures (798–835°C) reveal that magma derived from enriched lithospheric mantle not only provided a heat source for anatectic melting of the metasedimentary protoliths but was also an endmember component of the S‐type silicic magma. The studied early Triassic volcanics are inferred to have formed immediately before closure of the Paleo‐Tethys Ocean in this region, as the associated subduction would have generated an extensional setting in which the mantle‐derived upwelling and volcanic activity occurred. [ABSTRACT FROM AUTHOR]

By example of the silicate glasses with the compositions (33.3 – x)Li2O·xNa2O·66.7SiO2 and (33.3 – x)K2O·xNa2O·66.7SiO2 with purely cationic conductivity and chalcogenide glasses (Ag–Cu)0.33AsSe1.5 and (Ag–Cu)0.61AsSe1.5 with mixed ionic–electronic conductivity, consideration has been given to the describing of the mixed-alkali effect in bimetallic glasses in the framework of a microinhomogeneous-glass-structure model using additive schemes involving concentration dependences of conductivity of monometallic glasses with the monovalent metal content equal to that in the mixed glass. A satisfactory agreement between experimental and calculated data is demonstrated. Herein, in the alkaline silicate glasses the non-linear variation of the conductivity parameters is connected with the migration of two alkaline cations and sequential replacement of the conductivity mainly involving an ion by that involving another ion. In the studied chalcogenide glasses, a similar varying of electrical parameters is connected with the replacement of the majority current carrier upon the equivalent substituting of copper for silver in the glass bulk: the mixed, predominantly ionic conductivity is replaced by purely electronic one. [ABSTRACT FROM AUTHOR]

• Coal, sawdust and their mixtures were combusted in the fluidized bed of catalyst. • Addition of biomass increase the burnout degree up to 99.9% at 750 °С. • Addition of biomass decrease the environmental impact of combustion. • Combustion at 750 °C with the highest amount of sawdust is the most profitable. • Presence of CaO and MgO prevents SOx emission and slagging of heat exchange surfaces. The work is devoted to the study of combustion of brown coal, pine sawdust, and their mixtures in a fluidized bed of catalyst at 600–750°С. It is shown that an increase in the content of sawdust in a mixture with brown coal leads to an increase in the burnout degree of solid fuel from 94.4% to 99.9%, while the emission of greenhouse gases in the form of CO 2 CO and NO x is reduced (CO 2 from the biomass is not included in the balance). The high content of alkaline earth metal oxides (CaO and MgO) in the mineral part of brown coal, sawdust, and their mixtures eliminates the emission of sulfur oxides and the slagging of heat-exchange surfaces during the combustion in a fluidized bed of catalyst. The optimal temperature, when the highest burnout degree of the above fuels is achieved in the combustion is 750°С. It is also shown that the increase in temperature and the content of sawdust in the composition of the fuel mixtures has a positive effect on the economic and environmental process indicators. [Display omitted] [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]

The co-gasification of high moisture and high volatile content low-rank lignite (LG) coal and a common waste generated from the brewed tea leaves was studied in a fluidized bed gasification unit. Multiple experiments were conducted at different temperatures, ranging from 800 °C to 900 °C, at fixed operating parameters to elucidate the catalytic thermo-chemical impact on the gasifier performance parameters. The catalytic effect of alkali and alkaline earth metals (AAEMs), especially CaO, K 2 O, and Na 2 O present in the spent tea waste (STW) sample, on the product gas composition and performance parameters during the co-gasification experiments with LG was demonstrated. Mixed blends of LG and STW showed enhancement in the overall reactivity of the steam gasification runs, compared to the LG-only feed, primarily due to the change in the surface morphology, textures, and pore structures of the solid product ash samples, as identified with the electron spectroscopy analysis. Liquid and product samples were analyzed using characterization techniques such as Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) analytical techniques, along with the proximate, ultimate, and X-ray fluorescence (XRF) analysis of the gasification feed samples. An optimized blend ratio of 20 wt % of STW with LG sample enhanced the volumetric gas composition of H 2 and CH 4 gases from 52.03 % to 61.32 % and 3.98 %–5.45 % (on a dry-N 2 -free basis) with a relatively constant CO gas composition. It showed a reduced CO 2 composition from 28.64 % to 18.25 % (on a dry-N 2 -free basis) for the gasification temperature of 900 °C. Even at the lower gasification temperatures of 800 °C and 850 °C with LG + STW feed, steam gasification experiments showed relatively comparable or superior performance to gasification experiments at 900 °C with LG-only feed. The present study indicated a holistic way to utilize the spent tea waste generated from millions of homes and commercial establishments in various parts of the world with potential application towards synergistic gasification process with other conventional carbon-source materials. [Display omitted] • A novel study of co-gasification of lignite and spent tea waste. • Significantly enhanced hydrogen production with high CGE and CCE by adding STW to lignite. • Synergistic effect of alkali and alkaline earth metals (AAEMs) of STW on gasification performance. • Detailed feed and product characterization studies using XRF, TGA, FTIR, XRD, SEM, etc. • Holistic and sustainable utilization of millions of tonnes of STW generated worldwide. [ABSTRACT FROM AUTHOR]

Numerous industrial processes utilise gaseous chemical feedstocks to produce useful chemical products. Atmospheric and other small molecule gases, including anthropogenic waste products (e.g. carbon dioxide), can be viewed as sustainable building blocks to access value-added chemical commodities and materials. While transition metal complexes have been well documented in the reduction and transformation of these substrates, molecular complexes of the terrestrially abundant alkaline earth metals have also demonstrated promise with remarkable reactivity reported towards an array of industrially relevant gases over the past two decades. This review covers low oxidation state and hydrido group 2 complexes and their role in the reduction and transformation of a selection of important gaseous substrates towards value-added chemical products. [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]

Background: Imbalances in alkali elements (AEs) and alkaline earth elements (AEEs) cause reproductive disorders. However, it remains unclear whether AEs/AEEs in follicular fluid have a relationship with the serious reproductive disorder known as diminished ovarian reserve (DOR). Methods: A nested case‒control study was carried out in China. Follicular fluid samples from 154 DOR patients and 154 controls were collected and assessed for nine AEs/AEE levels. Both the mixed and single effects of the elements on DOR were estimated with a Bayesian kernel machine (BKMR) and logistic regressions. Results: The DOR group had higher median concentrations of Li, Na, and K in follicular fluid (all P values < 0.05). The logistic regression showed that compared with their lowest tertile, the high tertiles of K [OR:2.45 (1.67–4.43)], Li [OR: 1.89 (1.06–3.42)], and Cs [OR: 1.97 (1.10–3.54)] were significantly associated with the odds of DOR. The BKMR model reported that the DOR likelihood increased linearly across the 25th through 75th percentiles of the nine-AE/AEE mixture, while the AE group contributed more to the overall effect. Conclusion: This study revealed an association in which the likelihood of DOR increased with higher overall concentrations of AE/AEEs in follicular fluid. Among the nine detected elements, K, Li, and Cs exhibited significant individual associations with DOR. We provide new clues for the environmental factors on female fertility decline. Trial registration: Retrospectively registered. [ABSTRACT FROM AUTHOR]

Organic metal complexes (OMCs) transport trace metals (e.g. , Co, Ni, Cu) from surface soils, via the unsaturated zone, to sites of cave carbonate (speleothem) formation. OMCs clearly imprint on speleothem trace element chemistry, but the role of kinetic factors in the signal transfer process has yet to be elucidated. We investigated whether OMCs may viably link metal concentrations in stalagmites and local hydrology (i.e. , drip rate), via their time-sensitive dissociation (or 'decay') in the speleothem water thin-film. We performed competitive ligand exchange experiments using water and soil samples from eight geographically diverse Aotearoa New Zealand caves, providing a first comparative characterisation of speleothem-specific OMC kinetics. Critically, this approach corroborated that NOM ligands limit transition metal availability at the dripwater-speleothem interface, exhibiting stabilities on the order Cu ≈ Co > Ni, whereas organic complexation of the alkaline earth metals Mg and Sr was virtually absent. Systematic variations of OMC stability with natural organic matter characteristics were not observed amongst water samples, whilst enhanced complexation was clearly evident in the comparably organic-rich soil extracts. Our results imply that the supply of transition metals to speleothems is inversely related to drip rate, increasing with drip interval via the decay of OMCs. This process appears most sensitive on time-scales relevant to typical speleothem-forming settings (<0 to ca. 40 drips min−1, corresponding to ca. <5.6 mL min−1), and therefore provides a general, mechanistic link to a quantitative proxy of palaeoclimatic cave drip rates. [ABSTRACT FROM AUTHOR]

In this work we present a computational study of alkaline earth oxides (001) surfaces interfaced with water by means of density functional theory (DFT) in conjunction with ab initio molecular dynamics (AIMD) calculations. We studied the nature of MgO, CaO, SrO, and BaO (001) surfaces in contact with water. Results show that water dissociation is promoted as the alkaline earth metal becomes heavier. Similarly, the coordination number of the cation atoms with water molecules follows the same trend, indicating a more favorable interaction. The combined analysis of rumpling and pair distribution functions allows to provide a correspondence between reactivity of atoms on the surface and capability to coordinate water molecules. Except for MgO, the remaining surfaces display strong structural changes upon hydration, a relevant message when modelling hydrated surfaces. We also investigated the effect of the water thickness by adsorbing a water monolayer and bilayer to the surface. The findings of the study and the adopted approach could be of help for future studies of more complex systems or to provide fundamental rationalizations. [ABSTRACT FROM AUTHOR]

Birch reduction and similar dissolved metal‐type transformations hold significant importance in the organic synthesis toolbox. Historically, the field has been dominated by alkali metal reductants. In this study, we report that largely neglected, low‐reactive alkaline earth metals can become powerful and affordable reductants when used in a ball mill under essentially solvent‐free conditions, in the presence of ethylenediamine and THF as liquid additives. Calcium can reduce both electron‐deficient and electron‐rich arenes, with yields of products similar to those obtained with lithium metal. Magnesium reveals enhanced reducing power, enabling the reduction of benzoic acids while keeping electron‐rich aromatic moieties intact and allows for chemoselective transformations. The developed mechanochemical approach uses readily available and safer‐to‐handle metals, operates under air and ambient temperature conditions, and can be used for gram‐scale preparations. Finally, we demonstrate that the developed conditions can be used for other dissolved metal‐type reductive transformations, including reductive amination, deoxygenation, dehalogenation, alkene and alkyne reductions. [ABSTRACT FROM AUTHOR]

Birch reduction and similar dissolved metal‐type transformations hold significant importance in the organic synthesis toolbox. Historically, the field has been dominated by alkali metal reductants. In this study, we report that largely neglected, low‐reactive alkaline earth metals can become powerful and affordable reductants when used in a ball mill under essentially solvent‐free conditions, in the presence of ethylenediamine and THF as liquid additives. Calcium can reduce both electron‐deficient and electron‐rich arenes, with yields of products similar to those obtained with lithium metal. Magnesium reveals enhanced reducing power, enabling the reduction of benzoic acids while keeping electron‐rich aromatic moieties intact and allows for chemoselective transformations. The developed mechanochemical approach uses readily available and safer‐to‐handle metals, operates under air and ambient temperature conditions, and can be used for gram‐scale preparations. Finally, we demonstrate that the developed conditions can be used for other dissolved metal‐type reductive transformations, including reductive amination, deoxygenation, dehalogenation, alkene and alkyne reductions. [ABSTRACT FROM AUTHOR]

The number of crystal structures of pertechnetates derived from aqueous solutions has been expanded from seven to over 30. We report the conversion of NH4TcO4 to aqueous HtcO4 via acidic cation exchange. This is followed by the synthesis and structural elucidation of pertechnetate salts of alkaline earth (AE), transition metal I and lanthanoids (Ln) elements. Various degrees of hydration and coordination are discussed. Where possible, a comparison with the perrhenate homologues is made. The described syntheses and materials may be used as novel starting materials for extended technetium research. [ABSTRACT FROM AUTHOR]

ZnO is one of the most promising mid-high temperature thermoelectric materials because of low cost, easy preparation and favorable chemical stability. Herein, the influence mechanism of Alkaline earth metal Ba doping on the thermoelectric properties of ZnO was studied. It is found that Ba doping can effectively improve the carrier mobility and electrical conductivity for that Ba doping can shorten the Zn–O bond and enhance the overlap and hybridization of electron orbitals. The electronic density of states of Zn and O is significantly enhanced. The highest power factor of ∼7.95 μWcm−1K−2 was obtained at 873 K, which is ∼1.4 times higher than that of the undoped sample. Due to the decrease of Young's modulus caused by Ba doping and the enhancement of phonon scattering of heavy element, the thermal conductivity decreases obviously in the whole temperature range. Ba doping enhanced the effect of phonon glass-electron crystal, and the ZT value of ∼0.345 was obtained at 873 K, which is ∼3.52 times as that of the pristine ZnO. The results indicated that alkaline earth metal doping is an effective way to improve the thermoelectric properties of ZnO functional materials. [ABSTRACT FROM AUTHOR]

The phosphor-converted white light-emitting diodes (pc- w LEDs) are current research hotspot. To meet simultaneously the requirements of high chemical/thermal stability and color-rendering index (CRI), low correlated color temperature (CCT) for actual application is still not be perfectly achieved. Herein, we studied for the first time the incorporation of Ce3+ (blue-emitting) and Mn2+ (orange/red emission) into the dibarium magnesium phosphate ceramic (Ba 2 Mg(PO 4) 2 , BMP) for packaging of pc- w LEDs via remote 'capping' approach, which exhibits highly efficient color-tunable photoluminescence (PL) with splendid chemical/thermal stability, single-phase/full-color-PL, efficient energy transfer (ET). To reduce the impact of heterovalent substitution (Ba2+ ← Ce3+), the monovalent (Li+, Na+, K+) ion, respectively tridoped in BMP: Ce/Mn and played both roles as flux and charge compensator, were also studied/compared on the basis of PL efficiency, where Na+ is the most effective because of the lowest electronegativity mismatch between the Ba2+ and Na+. An alkaline-earth-metal-ion blending strategy via partial replacement of Ba2+ with Sr2+ was implemented to further regulate PL and obtain better parameters of CCT/CRI due to the variations of crystal field splitting. The site occupations of Ce/Na/Sr in Ba sites (CN = 8 and 7) and Mn in Mg site (CN = 6) were based on the comparisons of ion radius and confirmed by XRD/Rietveld analyses, where Ce/Na/Sr ions gave priority to occupy the Ba site with CN = 8 due to their much closer ion radius. Altogether, the stably composition-optimized BMP: Ce/Mn/Na/Sr has great potential application as a single-component color-tunable phosphor in n -UV pumped pc- w LEDs. The pc- w LED fabricated via remote 'capping' approach by combination of a n -UV chip with BMP: Ce/Mn/Na/Sr phosphor through Ce to Mn ET with the help of charge compensator of Na and the alkaline-earth-metal-ions blending by Ba/Sr replacement. [Display omitted] • Ce/Sr/Na occupied at Ba sites while Mn sited in Mg sites. • ET occurs efficiently from Ce to Mn. • Na + acts as charge balancer to improve PL efficiency. • Replacing partial Ba by Sr could regulate PL and improve ET efficiency. • pc- w LED via ' n -UV LED + white-emitting BMP: Ce/Mn/Na/Sr' is achieved. [ABSTRACT FROM AUTHOR]