Explore the vast range of titles available.

A generally applicable computer algorithm for the calculation of the seven molecular descriptors heat of combustion, logPoctanol/water, logS (water solubility), molar refractivity, molecular polarizability, aqueous toxicity (protozoan growth inhibition) and logBB (log (cblood/cbrain)) is presented. The method, an extendable form of the group-additivity method, is based on the complete break-down of the molecules into their constituting atoms and their immediate neighbourhood. The contribution of the resulting atom groups to the descriptor values is calculated using the Gauss-Seidel fitting method, based on experimental data gathered from literature. The plausibility of the method was tested for each descriptor by means of a k-fold cross-validation procedure demonstrating good to excellent predictive power for the former six descriptors and low reliability of logBB predictions. The goodness of fit (Q2) and the standard deviation of the 10-fold cross-validation calculation was >0.9999 and 25.2 kJ/mol, respectively, (based on N = 1965 test compounds) for the heat of combustion, 0.9451 and 0.51 (N = 2640) for logP, 0.8838 and 0.74 (N = 1419) for logS, 0.9987 and 0.74 (N = 4045) for the molar refractivity, 0.9897 and 0.77 (N = 308) for the molecular polarizability, 0.8404 and 0.42 (N = 810) for the toxicity and 0.4709 and 0.53 (N = 383) for logBB. The latter descriptor revealing a very low Q2 for the test molecules (R2 was 0.7068 and standard deviation 0.38 for N = 413 training molecules) is included as an example to show the limits of the group-additivity method. An eighth molecular descriptor, the heat of formation, was indirectly calculated from the heat of combustion data and correlated with published experimental heat of formation data with a correlation coefficient R2 of 0.9974 (N = 2031).

The interdiffusion behavior between NiCoW alloy and Nb 3 Al at 1000 °C was investigated. Based on the effective heat of formation model, the compounds at the interface are analyzed by calculating the effective heat of formation and establishing the map of favorable compound formation. It is concluded that the formation sequence of phases between the nickel-based alloy and Nb 3 Al is Ni 6 Nb 7  → Co 2 Nb/Ni 6 Nb 7  + Nb ss  → Ni 3 Nb → W-rich phase. The results of this paper provide a reference for the phase formation sequence law of multicomponent interface between Nb 3 Al and the matrix alloy.

This study presents a predictive model for condensed-phase heats of formation of metal-containing energetic complexes (MCECs) and energetic metal-organic frameworks (EMOFs), leveraging a dataset of 148 compounds. Using elemental composition, triazole rings, and metal presence, the model achieves high accuracy (R2 > 0.94, mean absolute error (MAE) ≈ 390 kJ/mol) for screening high-energy materials. It outperforms prior methods, particularly for polycyclic systems, offering a practical tool for safer design and risk assessment in defense and industrial applications. [Display omitted] •A robust and transparent model is developed for predicting condensed phase heats of formation of MCECs and EMOFs.•The model leverages elemental composition, triazole ring content, and key metal atoms as structural descriptors.•Validation against 148 diverse experimental compounds demonstrates high predictive accuracy and generalizability.•The approach significantly improves predictions for complex and polycyclic energetic materials compared to previous models.•Reliable predictions support safer process design, risk assessment, and rational screening of hazardous energetic materials.

This work reported the first-principles calculations for the compositional dependence of the energetic, electronic, and magnetic properties of the bimetallic Fe-Pt alloys at ambient conditions. These hybrid alloys have gained substantial attention for their potential industrial applications, due to their outstanding magnetic and structural properties. They possess high magnetocrystalline anisotropy, density, and coercivity. Four Fe-Pt alloys, distinguished by compositions and space groups, were considered in this study, namely P4/mmm-FePt, I4/mmm-Fe3Pt, Pm-3m-Fe3Pt, and Pm-3m-FePt3. The calculated heats of formation energies were negative for all Fe-Pt alloys, demonstrating their stability and experimentally higher formation probability. The P4/mmm-FePt alloy had the lowest magnetic moment, leading to durable magnetic hardness, which made this alloy the most suitable for permanent efficient magnets, and magnetic recording media applications. Moreover, it possessed a relatively large magnetocrystalline anisotropy energy value of 2.966 meV between the in-plane [100] and easy axis [001], suggesting an inside the plane isotropy.

The heats of formation of thirty-five molecules containing antimony atoms have been calculated using G4(MP2)-XK, B3LYP, M06, M06-HF, M06-2X, BMK, wB97XD, and TPSSh atomization. The discrepancies between the predicted and the reported heats of formation vary in the range of 0.0–83 kcal mol −1 when compared with experimental and literature. The best agreement with experimental and literature data was achieved by using G4(MP2)-XK. The functionals used did not show results as good as G4(MP2)-XK. In its development, G4 (MP2)-XK showed itself comparable in accuracy to the G4(MP2)-6X. Importantly, the precision of G4(MP2)-XK for heavier elements such as antimony is similar to that of the first- and second-row species, although it contains parameters that are only adjusted to the systems of the first two rows. In this study, we can observe that G4(MP2)-XK has excellent requirements for elements such as antimony and leads us to believe that its scope will be further expanded in future studies with formation enthalpy such as iodine and xenonium.

Electronegativity is a key property of the elements. Being useful in rationalizing stability, structure and properties of molecules and solids, it has shaped much of the thinking in the fields of structural chemistry and solid state chemistry and physics. There are many definitions of electronegativity, which can be roughly classified as either spectroscopic (these are defined for isolated atoms) or thermochemical (characterizing bond energies and heats of formation of compounds). The most widely used is the thermochemical Pauling’s scale, where electronegativities have units of eV 1/2 . Here we identify drawbacks in the definition of Pauling’s electronegativity scale—and, correcting them, arrive at our thermochemical scale, where electronegativities are dimensionless numbers. Our scale displays intuitively correct trends for the 118 elements and leads to an improved description of chemical bonding (e.g., bond polarity) and thermochemistry. Pauling’s electronegativity scale has a fundamental value and uses accessible thermochemical data, but fails at predicting the bonding behavior for several elements. The authors propose their thermochemical scale based on experimental dissociation energies that provides dimensionless values for the electronegativity and recovers the correct trends throughout the periodic table.

Anyons are quasiparticles that, unlike fermions and bosons, show fractional statistics when two of them are exchanged. Here, we report the experimental observation of anyonic braiding statistics for the ν = 1/3 fractional quantum Hall state by using an electronic Fabry–Perot interferometer. Strong Aharonov–Bohm interference of the edge mode is punctuated by discrete phase slips that indicate an anyonic phase θ anyon = 2π/3. Our results are consistent with a recent theory that describes an interferometer operated in a regime in which device charging energy is small compared to the energy of formation of charged quasiparticles, which indicates that we have observed anyonic braiding. An interferometer device is used to detect the quantum-mechanical phase that is gained when two anyons are braided around each other. The fractional value of the phase proves that these quasiparticles are neither bosons nor fermions.

Photocatalytic two-electron oxygen reduction to produce high-value hydrogen peroxide (H 2 O 2 ) is gaining popularity as a promising avenue of research. However, structural evolution mechanisms of catalytically active sites in the entire photosynthetic H 2 O 2 system remains unclear and seriously hinders the development of highly-active and stable H 2 O 2 photocatalysts. Herein, we report a high-loading Ni single-atom photocatalyst for efficient H 2 O 2 synthesis in pure water, achieving an apparent quantum yield of 10.9% at 420 nm and a solar-to-chemical conversion efficiency of 0.82%. Importantly, using in situ synchrotron X-ray absorption spectroscopy and Raman spectroscopy we directly observe that initial Ni-N 3 sites dynamically transform into high-valent O 1 -Ni-N 2 sites after O 2 adsorption and further evolve to form a key *OOH intermediate before finally forming HOO-Ni-N 2 . Theoretical calculations and experiments further reveal that the evolution of the active sites structure reduces the formation energy barrier of *OOH and suppresses the O=O bond dissociation, leading to improved H 2 O 2 production activity and selectivity. Here, the authors explore how Ni single-atom sites on carbon nitride evolve under photocatalytic conditions. They show that this evolution plays a pivotal role in enhancing photocatalytic H 2 O 2 production.

Designing highly durable and active electrocatalysts applied in polymer electrolyte membrane (PEM) electrolyzer for the oxygen evolution reaction remains a grand challenge due to the high dissolution of catalysts in acidic electrolyte. Hindering formation of oxygen vacancies by tuning the electronic structure of catalysts to improve the durability and activity in acidic electrolyte was theoretically effective but rarely reported. Herein we demonstrated rationally tuning electronic structure of RuO 2 with introducing W and Er, which significantly increased oxygen vacancy formation energy. The representative W 0.2 Er 0.1 Ru 0.7 O 2-δ required a super-low overpotential of 168 mV (10 mA cm − 2 ) accompanied with a record stability of 500 h in acidic electrolyte. More remarkably, it could operate steadily for 120 h (100 mA cm − 2 ) in PEM device. Density functional theory calculations revealed co-doping of W and Er tuned electronic structure of RuO 2 by charge redistribution, which significantly prohibited formation of soluble Ru x>4 and lowered adsorption energies for oxygen intermediates. There is an increasing interest in understanding how defect chemistry can alter material reactivity. Here, authors tune the electronic structure of RuO 2 by introducing W and Er dopants that boost acidic oxygen evolution performances by limiting oxygen vacancy formation during catalysis.

Single-atom catalysts provide an effective approach to reduce the amount of precious metals meanwhile maintain their catalytic activity. However, the sluggish activity of the catalysts for alkaline water dissociation has hampered advances in highly efficient hydrogen production. Herein, we develop a single-atom platinum immobilized NiO/Ni heterostructure (Pt SA -NiO/Ni) as an alkaline hydrogen evolution catalyst. It is found that Pt single atom coupled with NiO/Ni heterostructure enables the tunable binding abilities of hydroxyl ions (OH*) and hydrogen (H*), which efficiently tailors the water dissociation energy and promotes the H* conversion for accelerating alkaline hydrogen evolution reaction. A further enhancement is achieved by constructing Pt SA -NiO/Ni nanosheets on Ag nanowires to form a hierarchical three-dimensional morphology. Consequently, the fabricated Pt SA -NiO/Ni catalyst displays high alkaline hydrogen evolution performances with a quite high mass activity of 20.6 A mg −1 for Pt at the overpotential of 100 mV, significantly outperforming the reported catalysts. While H 2 evolution from water may represent a renewable energy source, there is a strong need to improve catalytic efficiencies while maximizing materials utilization. Here, authors examine single-atom Pt on nickel-based heterostructures as highly active electrocatalysts for alkaline H 2 evolution.