Periodic Table Research Articles

The Role of the Periodic Table of the Elements of Green and Sustainable Chemistry in a High School Educational Context

The Periodic Table of the Elements of Green and Sustainable Chemistry (PT-GSC) represents a potentially meaningful tool for teaching and learning Green Chemistry. However, there is a lack of studies exploring the application of the PT-GSC in educational contexts. To contribute to filling this gap, a qualitative and participant approach was developed to examine the effects of using the PT-GSC in a high school setting, with a focus on analyzing the associated challenges and opportunities. Over a five-week period, 23 high school students enrolled in a chemistry course at a public school in Brazil worked in small groups to develop solutions for a case study addressing socio-scientific issues related to water scarcity in the local region using elements from the PT-GSC. Results from both the pre- and post-questionnaires, along with the written case study resolutions, provide evidence of the students’ knowledge gains, particularly in critical scientific literacy for Green and Sustainable Chemistry Education. The findings showed that the PT-GSC is an interdisciplinary tool for introducing students to Green Chemistry concepts within the broader societal and scientific ecosystem. The implementation of novel case studies incorporating elements from the PT-GSC is a way to support our ongoing work with students and the public, contributing to a sustainable future.

Pertechnetates - A Structural Study Across the Periodic Table.

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.

Explainable machine learning accelerated density functional theory prediction for diffusive transport behaviour of elements in aluminium matrix and graphene/aluminium interface

In this paper, the diffusive migration behaviour of alloy atoms in aluminium matrix and different types of graphene/aluminium interfaces is systematically investigated by using a machine learning accelerated density functional theory. A small sample dataset is established by first principles calculation, the types of input and output eigenvalues are determined by feature engineering, and the number of input features for perfect interfaces, defective interfaces, and aluminium matrix are finally determined to be 6, 5, and 4 by taking into account the effects of model complexity and prediction accuracy. With a five-fold crossover and by comparing more than a dozen machine learning models, the CatBoost algorithm possesses the lowest error as well as a better coefficient of determination. We further optimized the CatBoost algorithm with further parameters and adjusted the regularization term coefficients to avoid the risk of overfitting. The impact of each feature on the model prediction results was quantitatively described by constructing a matrix of SHAP values. The best performing Catboost model was used to predict the full periodic table data, which in turn was used to screen out the elemental species that are easy to move towards the graphene/aluminium composite interface. Those alloying elements are beneficial for modifying the defective graphene in the composite by comparing the results of elemental diffusive migration in the aluminium matrix as well as at different graphene/aluminium interfaces. The results of machine learning accelerated first principles calculations can provide a theoretical basis for further development of new aluminium alloy composite.

Integrated annotation prioritizes metabolites with bioactivity in inflammatory bowel disease.

Microbial biochemistry is central to the pathophysiology of inflammatory bowel diseases (IBD). Improved knowledge of microbial metabolites and their immunomodulatory roles is thus necessary for diagnosis and management. Here, we systematically analyzed the chemical, ecological, and epidemiological properties of ~82k metabolic features in 546 Integrative Human Microbiome Project (iHMP/HMP2) metabolomes, using a newly developed methodology for bioactive compound prioritization from microbial communities. This suggested >1000 metabolic features as potentially bioactive in IBD and associated ~43% of prevalent, unannotated features with at least one well-characterized metabolite, thereby providing initial information for further characterization of a significant portion of the fecal metabolome. Prioritized features included known IBD-linked chemical families such as bile acids and short-chain fatty acids, and less-explored bilirubin, polyamine, and vitamin derivatives, and other microbial products. One of these, nicotinamide riboside, reduced colitis scores in DSS-treated mice. The method, MACARRoN, is generalizable with the potential to improve microbial community characterization and provide therapeutic candidates.

Periodic Table of Food Initiative for generating biomolecular knowledge of edible biodiversity.

Periodic Table of Food Initiative for generating biomolecular knowledge of edible biodiversity.

A General Model of Impact Sensitivity for Nitrogen-Rich Energetic Materials: A Combined Incremental Theory and Genetic Function Approximation Study.

In this paper, we report the first example of impact sensitivity prediction based on the genetic function approximation (GFA) as a regression method. The prediction is applicable for a wide variety of chemical families, which include nitro compounds, peroxides, nitrogen-rich salts, heterocycles, etc. Within this work, we have obtained 7 empirical models (with 27-32 basis functions), which all provide 0.80≤R2≤0.83 and 7.2 J≤RMSE≤7.8 J (for 450 training set compounds) and 0.64≤R2≤0.70 and 11.2 J≤RMSE≤12.4 J (for 170 test set compounds). The models were developed using Friedman Lack-of-Fit as a scoring function, which allows avoiding an overfitting. All the models have simple descriptors as basis functions and include linear splines. Furthermore, the applied descriptors do not require expensive calculation procedures, namely, non-empirical quantum-chemical calculations, complex iterative procedures, real space electron density analysis, etc. Most descriptors are based on structural and topological analysis and a part of them require very cheap semi-empirical PM6 calculations. The prediction takes a few minutes as an average, and most of the time is for the structure preparation and manual calculation of the descriptor "Increment", which is based on our recent incremental theory.

X-ray diffraction and photoelectron spectroscopy analyses of MXene electrode material used in energy storage applications – a review

Abstract X-rays have many uses in screening and materials characterization applications. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis are among them. From the XRD data, a crystal structure can be determined by analysis of the XRD pattern, intensity, and positions of the peaks. Information about the crystallographic space group, lattice parameters, preferred orientation, and crystallite size can be derived. XPS examines the surface chemical state of a sample. This review will focus exclusively on MXene compounds and their analysis using XRD and XPS. MXene are layered compounds with a strong potential for application in energy storage. Since MXenes are two-dimensional (2D) transition metal carbides and nitride, the material exhibit signals indicating the presence of specific transition elements, 1s carbon, and 1s oxygen. Additionally, there is a possibility of detecting an element from group 13 or 14 of the periodic table, such as aluminum, nitrogen, or fluorine. A comprehensive study based on XRD and XPS analytical techniques of 2-dimensional electrode materials may provide advancement in the field of energy storage. MXene especially deserve attention due to their remarkable structural and electrochemical characteristics, such as conductivity, topological, and surface area, which attracted numerous researchers worldwide.

Tris(pentafluorophenyl)corrolatoindium(III) – A Long-awaited Metallocorrole: Synthesis and Characterization

The first attempts at the synthesis of an indium corrole compound were synthesized in the late 80s, but it has not been possible to obtain and characterize such complex completely, and the indium part of metallocorrole’s periodic table remained unfilled. In this work, an efficient insertion of indium into the 5,10,15-tris(pentafluorophenyl)corrole was achieved. The obtained 5,10,15-tris(pentafluorophenyl)corrolato indium(III) derivatives has been successfully characterized by relevant analytical techniques and some photophysical and electrochemical features were studied and investigated for the first time. As a novel research, 19F-19F COSY NMR technique was employed for the first time in corrole chemistry and the obtained results were further compared to the geometry-optimized molecular structure via density functional theory (DFT) calculations.

Applying the modified UV-activated TOP assay to complex matrices impacted by aqueous film-forming foams

Per- and polyfluoroalkyl substances (PFAS) are a large chemical family, and numerous chemical species can co-exist in environmental samples, especially those impacted by aqueous film-forming foams (AFFFs). Given the limited availability of chemical standards, capturing the total amount of PFAS is challenging. Thus, the total oxidizable precursor (TOP) assay has been developed to estimate the total amount of PFAS via the oxidative conversion of precursors into perfluorocarboxylic acids (PFCAs). This study aims to enhance the robustness of the TOP assay by replacing heat activation with UV activation. We evaluated the molar yields of known precursors in water in the presence of varying levels of Suwannee River natural organic matter (SRNOM) and in two soils. The impact of UV activation was also evaluated in two soils spiked with three well-characterized AFFFs, six AFFF-impacted field soils, and nine rinse samples of AFFF-impacted stainless-steel pipe. In the presence of 100 mg/L SNROM, 6:2 fluorotelomer sulfonate (FTS), 8:2 FTS, and N-ethyl perfluorooctane sulfonamidoacetic acid (N-EtFOSAA) in deionized water had good molar recovery as PFCAs (average of 102 ± 9.8 %); at 500 mg/L SNROM, the recovery significantly dropped to an average of 51 ± 19 %. In two soils (with 4 % and 8.8 % organic matter) with individual precursor spikes, the average molar recovery was 101 ± 9.4 %, except N-EtFOSAA, which had a reduced recovery in the soil with 8.8 % organic matter (OM). UV-activated assays outperformed heat-activated ones, especially in AFFF-impacted soils and pipe extract samples, with an average of 1.4–1.5× higher PFCA recovery. In almost all test samples, UV activation resulted in a notable shift towards longer PFCA chain lengths, particularly for samples with high OM content. The study confirmed the advantages of UV activation, including a significantly shortened exposure time (1 h vs. 6 h) and reduced matrix effects from OM due to the dual functions of UV in activating persulfate and photodegrading OM.

Laboratory rotational spectroscopy of the magnesium-carbon chains MgC[formula omitted]H and MgC[formula omitted

Recent advances in circumstellar metal chemistry and laser-coolable molecules have spurred interest in the spectroscopy and electronic properties of alkaline earth metal-bearing polyatomic molecules. We report the microwave rotational spectra of two members of this important chemical family, the linear magnesium-carbon chains MgC4H and MgC3N, detected with cavity Fourier transform microwave spectroscopy of a laser ablation-electric discharge expansion. The rotation, fine, and hyperfine parameters have been derived from the precise laboratory rest frequencies. These experimental results, combined with a theoretical quantum chemical analysis, confirm the recent identification of MgC4H and MgC3N in the circumstellar envelope of the evolved carbon-rich star IRC+10216. The spectroscopic data also provide insight into the structural and electronic properties that influence the metal-based optical cycling center in this unique class of laser-coolable polyatomics.

Electronic Prediction of Chemical Contaminants in Aroma of Brewed Roasted Coffee and Quantification of Acrylamide Levels.

The aim of this research was to apply an electronic device as indirect predictive technology to evaluate toxic chemical compounds in roasted espresso coffee. Fresh coffee beans were subjected to different thermal treatments and analyzed to determine volatile organic compounds, content of acrylamide and 5-hydroxymethylfurfural, sensory characteristics and electronic nose data. In total, 70 different volatile compounds were detected and grouped into 15 chemical families. The greatest percentage of these compounds were furans, pyrazines, pyridines and aldehydes. The positive aroma detected had the intensity of coffee odor and a roasted aroma, whereas the negative aroma was related to a burnt smell. A linear relationship between the toxic substances and the sensory defect was established. A high sensory defect implied a lower content of acrylamide and a higher content of 5-hydroxymethylfurfural. Finally, electronic signals were also correlated with the sensory defect. This relationship allowed us to predict the presence of these contaminants in the roasted coffee beverage with an indirect method by using this electronic device. Thus, this device may be useful to indirectly evaluate the chemical contaminants in coffee beverages according to their sensory characteristics.

“Searching for order at all levels”. Antonio Lima-de-Faria (July 4, 1921 – December 27, 2023)

“Searching for order at all levels”. Antonio Lima-de-Faria (July 4, 1921 – December 27, 2023)

Sequential decay analysis of $^{235}$U(n$^{th}$,f) reaction using fragmentation approach

Abstract Numerous experimental and theoretical observations conclude that the probability of the three fragment emission (ternary fission) or the binary fission increases when one proceeds towards the heavy mass region of nuclear periodic table. The collinear cluster tripartition (CCT) channel of $^{235}$U(n$^{th}$,f) reaction is studied and it was observed that the CCT may be a sequential process or a simultaneous emission phenomena. Till now, different approaches are introduced to study the CCT process as a simultaneous process or sequential process, but the decay dynamics of these modes is not fully explored. It will be of interest to identify the three fragments of the sequential process and to explore their related dynamics using some excitation energy dependent approach. Hence, in present work, an attempt is made to study the sequential decay mechanism of $^{235}$U(n$^{th}$,f) reaction using quantum mechanical fragmentation theory (QMFT). The decay mechanism is considered in two steps, where initially the nucleus splits into an asymmetric channel. In the second step, the heavy fragment obtained in the first step divides into two fragments. Stage I analysis is done by calculating the fragmentation potential and the preformation probability for the spherical and deformed choice of the decaying fragments. The most probable fragment combination of stage I are identified in view the dips in the fragmentation structure, and the corresponding maxima's of the preformation probability ($P_0$). The excitation energy of the decay channel is calculated using an iteration process. The obtained excitation energy of the identified heavy fragments is further used for the fragmentation analysis, and the subsequent binary fragments of the sequential process are obtained. The identified three fragments of the sequential process are in agreement with the experimental observation and are found nearby the neutron or proton shell closure. Finally, the kinetic energy of the observed fragments is calculated and the middle fragment of the CCT mechanism is identified.

Exploring the aromatic typicity of blended red wines from geographically close sub-regions in AOC Corbières: a sensory and chemical approach

Several studies have reported a terroir effect on monovarietal wines originating from geographically close areas, using both aromatic and sensory analyses. However, few studies have evaluated this effect on blended wines, a widespread practice that is recognised as adding great complexity to wines. This study aimed to discriminate blended wines produced in five sub-regions of the Corbières AOC according to their aromatic and sensory profiles and across two vintages: 2018 and 2019. The wines’ aromatic profiles were semi-quantified using HS-SPME-GC-MS, and the sensory descriptors enabling the differentiation of the wines were identified by QDA analysis. Although blending is a frequently used process adapted for the production of homogeneous wines within an appellation, the sensory and chemical profiles enabled us to differentiate wines of the Lagrasse and Lézignan sub-regions from those of the Maritime and Durban sub-regions. The variation in intensity of red fruit jam notes may be linked to terroir factors relating to the micro-climatic conditions. Wines from vineyards in coastal regions or at higher elevations were discriminated by lower intensities of this descriptor. However, other discriminating descriptors, such as amyl, earthy or cooked vegetables, could be related to the winemaking process. Correlations were found between the tendencies observed regarding the sensory markers (such as red fruit jam, butter/lactic, amylic, cooked vegetable) and those regarding the chemical families of aroma or specific aroma compounds (such as ethyl esters, higher alcohols and sulphur compounds), whose production is particularly affected by the winemaking processes. Finally, this study shows that it is possible to discriminate blended wines from different geographically close regions, and that the terroir factor with the greatest influence on this discrimination seems to be linked to winemaking processes, including the type of blending carried out.

R Radiological Risk Assessment Of 222 Radon Concentration And Annual Effective Dose Calculation In Groundwater From Zakho, Iraq

Radon, the heaviest of noble gases in the periodic table, is a naturally occurring radioactive nuclide found in rocks, soil, and water. It has gained increasing attention in recent research due to its association with cancer. This study focused on assessing the potential radioactive risks associated with water usage in Zakho, Iraq, by analyzing 16 groundwater samples collected from the primary water source. Alpha spectrometry with RAD7 and RAD-H2O accessories from Durridge CO was employed for assay purposes. The measured 222Rn concentrations ranged from 0.21 ± 0.1 to 19.75 ± 4.8 BqL−1, with an average of 8.90 Bq. −1. The recorded values indicate that 31% of the data surpasses the specified United States Environmental Protection Agency (USEPA) limit of 11.1 BqL−1. Notably, the evaluation of the total annual effective dose revealed significant age-related variations. Specifically, 62% of infant samples and 68% of children samples exceeded the acceptable limit of 100 μSv/y, while 25% of adult samples surpassed the World Health Organization (WHO) recommended threshold. The obtained data align with similar studies conducted globally, emphasizing the need for continuous radon monitoring during water consumption. The findings advocate for proactive measures to ensure the safety of these water sources, addressing the pressing concern of radon-related health risks.

Exploring the Role of Lactic Acid Bacteria Blends in Shaping the Volatile Composition of Fermented Dairy and Rice-Based Beverages: A Step towards Innovative Plant-Based Alternatives.

Plant-based products are currently gaining consumers' attention due mainly to the interest in reducing the consumption of foods of animal origin. A comparison of two fermentative processes utilizing dairy milk and a rice beverage was conducted in the present study, using a commercial lactic acid bacteria strain combination (CH) and a selected mixture of lactic acid bacteria from yogurt (LLV). Cell viability and physicochemical characteristics (total soluble solids, pH, total acidity) were determined to describe the samples before and after fermentation, as well as the volatile composition (gas chromatography-mass spectrometry) and the sensory profile (Rate-All-That-Apply test). Results of the analyses showed significant differences among samples, with a clear effect of the raw material on the volatile profile and the sensory characterization, as well as a significant effect of the microbial combination used to ferment the matrices. In general, the selected LLV strains showed a greater effect on both matrices than the commercial combination. Dairy samples were characterized by a volatile profile represented by different chemical families (ketones, lactones, acids, etc.), which contributed to the common descriptive attributes of milk and yogurt (e.g., dairy, cheese). In contrast, rice beverages were mainly characterized by the presence of aldehydes and alcohols (cereal, legume, nutty).

Gas and Liquid Chromatography Mass Spectrometry as a Tool for Elucidating Volatile Organic Compounds (VOCs) and Metabolites in Maternal Milk: A Perspective on Infants’ Health Risk Assessment

Maternal milk is pivotal for infants’ nutrition. It also portrays the chemical burden to which the mother has been exposed. One of the chemical families that is prevalent and related to potential toxic effects are volatile organic compounds (VOCs). In the present study, motivated by the scarcity of works dealing with concomitant VOC and metabolite determination in maternal milk, two new gas/liquid chromatography tandem mass spectrometry (GC-MS/MS, LC-MS/MS) methods for the simultaneous measurement of 25 VOCs and 9 of their metabolites, respectively, in maternal milk were developed and applied to 20 maternal milk samples collected from mothers in Greece. In parallel, a headspace solid-phase microextraction (HS-SPME)–GC-MS method was employed for the untargeted screening of chemicals. Low detection rates for benzene, toluene, styrene and p,m-xylenes, and three of their metabolites, namely N-acetyl-S-(benzyl)-L-cysteine (BMA, metabolite of toluene), 3-methylhippuric (3-MHA, metabolite of xylenes) and mandelic acid (MA as DL and R isomers, metabolites of styrene and ethylbenzene), were evidenced in concentrations varying from <lower limit of quantification (LLOQ) to 0.79 ng mL−1. HS-SPME–GC-MS disclosed the presence of common maternal milk constituents such as fatty acids. Nevertheless, bisphenol-A, bisphenol derivatives and phthalates were also detected. The infants’ health risk assessment demonstrated a low risk and negligible carcinogenic risk, yet the detection of these compounds should not be underestimated.

Thorium(IV)-antimony complexes exhibiting single, double, and triple polar covalent metal-metal bonds.

There is continued burgeoning interest in metal-metal multiple bonding to further our understanding of chemical bonding across the periodic table. However, although polar covalent metal-metal multiple bonding is well known for the d and p blocks, it is relatively underdeveloped for actinides. Homometallic examples are found in spectroscopic or fullerene-confined species, and heterometallic variants exhibiting a polar covalent σ bond supplemented by up to two dative π bonds are more prevalent. Hence, securing polar covalent actinide double and triple metal-metal bonds under normal experimental conditions has been a fundamental target. Here we exploit the protonolysis and dehydrocoupling chemistry of the parent dihydrogen-antimonide anion, to report one-, two- and three-fold thorium-antimony bonds, thus introducing polar covalent actinide-metal multiple bonding under normal experimental conditions between some of the heaviest ions in the periodic table with little or no bulky-substituent protection at the antimony centre. This provides fundamental insights into heavy element multiple bonding, in particular the tension between orbital-energy-driven and overlap-driven covalency for the actinides in a relativistic regime.

Pushing The Extreme of Multicentre Bonding: Planar Pentacoordinate Hydride.

Planar hypercoordination has sparkled interest among the researchers from last few decades. Most of the elements in the Periodic Table have shown this remarkable structural feature. However, the smallest element, hydrogen, is missing in the list. No evidence is there in the literature. Herein, we introduce the first planar pentacoordinate hydrogen atom (ppH) in the global minimum geometry of Li5 H6 - cluster. Bonding analysis indicates that the central hydrogen atom is stabilized by multicentre bonding with five surrounding Li atoms. Natural charge analysis reveals that the central hydrogen is acting like a hydride which is strongly attracted by the positively charged surrounding lithium centres. The ppH structure is stabilized by strong electrostatic attraction as well as extensive multicentre bonding. Aromaticity has no role to play here. The cluster is dynamically stable and is expected to be detected in gas phase.

Pushing The Extreme of Multicentre Bonding: Planar Pentacoordinate Hydride

AbstractPlanar hypercoordination has sparkled interest among the researchers from last few decades. Most of the elements in the Periodic Table have shown this remarkable structural feature. However, the smallest element, hydrogen, is missing in the list. No evidence is there in the literature. Herein, we introduce the first planar pentacoordinate hydrogen atom (ppH) in the global minimum geometry of Li5H6− cluster. Bonding analysis indicates that the central hydrogen atom is stabilized by multicentre bonding with five surrounding Li atoms. Natural charge analysis reveals that the central hydrogen is acting like a hydride which is strongly attracted by the positively charged surrounding lithium centres. The ppH structure is stabilized by strong electrostatic attraction as well as extensive multicentre bonding. Aromaticity has no role to play here. The cluster is dynamically stable and is expected to be detected in gas phase.