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Discoverers of boron: (a) Joseph Louis Gay-Lussac (1778-1850), (b) Louis Jacques Thenard (1777-1857), (c) Humphry Davy (1778-1829).
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Boron is a unique element, being the only element, all known polymorphs of
which are superhard, and all of its crystal structures are distinct from any
other element. The electron-deficient bonding in boron explains its remarkable
sensitivity to even small concentrations of impurity atoms and allows boron to
form peculiar chemical compounds with ve...
Citations
... It is not found alone in nature and forms many compounds. The compounds formed with the elements calcium (Ca), magnesium (Mg) and sodium (Na) are called natural compounds (Oganov and Solozhenko, 2009). It is thought that the combination of metal and non-metal properties, as well as the tendency to bond with oxygen, are the main reasons for the existence of more than two hundred derivatives. ...
Objective: In this study, it was aimed to determine the effect of boron added to the drinking water of rats on serum boron levels, calcium, magnesium and phosphorus concentrations and the changes that may occur in hematological parameters. Materials and Methods: A total of 12 250-350 g Wistar Albino male rats, 6 in the control group and 6 in the experimental group, were used in the study. The rats were fed ad libitum and 2 mg/day/rat/25 ml borax decahydrate (Sigma) was added to the drinking water. At the end of 14 days, the rats were decapitated. Serum boron analysis by ICP-OES was performed according to Tokay and Bagdat (2022). In addition; Ca, Mg, P concentrations were determined with a biochemical analyzer device. Results: When the serum boron levels of the rats were analysed, those in the experimental group were significantly higher (p:0.0107) than those in the control group. However, there was no effect on haematological parameters or serum calcium, magnesium and phosphorus levels. Conclusion: As a result of this study, it was determined that boron given to rats with drinking water had no effect on the minerals examined. However, it was concluded that more information could be obtained with more comprehensive studies on this subject.
... Due to its trivalent nature, boron has a propensity to form electron-deficient bonding configurations, where electrons are delocalized between three or more atoms, resulting in a bulk phase that can consist of numerous polymorphs (19). This structural diversity is more or less maintained in the polymorphic nature of borophene at the atomically thin limit (20). ...
Inspired by the success of graphene, two-dimensional (2D) materials have been at the forefront of advanced (opto-)nanoelectronics and energy-related fields owing to their exotic properties like sizable bandgaps, Dirac fermions, quantum spin Hall states, topological edge states, and ballistic charge carrier transport, which hold promise for various electronic device applications. Emerging main group elemental 2D materials, beyond graphene, are of particular interest due to their unique structural characteristics, ease of synthetic exploration, and superior property tunability. In this review, we present recent advances in atomic-scale studies of elemental 2D materials with an emphasis on synthetic strategies and structural properties. We also discuss the challenges and perspectives regarding the integration of elemental 2D materials into various heterostructures.
... Boron is unique among elements in that all of its crystal structures are diferent from any other element, and all of its known polymorphs are tough [6]. Iwami and Toshio [7] argue that the placement of boron in the periodic table makes it difcult to explain bonding in boron-rich materials using traditional valence criteria. ...
In its crystalline state, the α-icosahedral nanosheet of boron demonstrates superconductivity and thermal electronic properties. Mathematical research on a graph’s structure yields a graph descriptor, a numerical measure. Chemical graph theory employs connectivity descriptors to analyze molecular structures, providing crucial insights into many chemical compounds’ chemical and biological characteristics. These characteristics benefit physicists, chemists, and medical and pharmaceutical specialists. In this paper, the idea of reverse degree–based RdM-polynomial is initiated, and differential and integral operators are computed. We formulate reverse degree–based topological descriptors based on this concept. In this paper, we examine the boron α-icosahedral nanosheet for this technique. We looked at the physicochemical properties of boron α-icosahedral nanosheets using reverse degree–based topological descriptors and best-fit linear regression models to get an idea of what they are. Researchers are hoping that this strategy will lead them into new areas where they can investigate related studies.
... Due to the tendency of boron atoms to form three-center electron-deficient B-B bonds, a stable state of crystalline boron is achieved through the formation of complex structural motifs, including B12 icosahedra [1]. They are the structural blocks of both allotropes of elemental boron [2] and complex boride phases [3], which demonstrate high hardness, low density and thermal endurance, which opens up prospects for the search for new materials based on them [4,5]. One direction of such a search is higher metal borides [6,7]. ...
The geometry and cohesive energy of isolated clusters — fragments of icosahedral boron compounds — with Al, Mg, C, O, Si substitution atoms have been calculated within the framework of DFT electron density theory using the Gamess software package. Electron density distribution between atoms has been investigated. The bulk modulus of the B12 cluster has been calculated on the basis of quantum chemical calculations and a thermodynamic series of cluster hardness has been constructed: HB22O2 > HB22C2 > HB24 > HB22Si2 > HB22Al2 > HB22Mg2. The calculated bulk modulus and hardness values based on the results of the first-principles study of the clusters are in good agreement with the experimental data for compounds with similar chemical compositions. The technique is applicable to the prediction of the choice of substitutional atoms in icosahedral boron groupings. Keywords: boron, boride, isolated cluster model, bulk modulus, hardness.
... With its intrinsic electron deficiency and more complex bonding nature than carbon, 1 boron ranks among the most chemically flexible elements, forming at least sixteen elemental bulk polymorphs, 2 as well as a plethora of cluster structures of diverse sizes, 3 including (quasi-)planar forms. 4 On that front, theoretical predictions 5,6 paved the way for the first experimental synthesis of two-dimensional (2D) boron structures, called borophenes, on a Ag(111) substrate in 2015. ...
Borophene stands out among elemental two-dimensional materials due to its extraordinary physical properties, including structural polymorphism, strong anisotropy, metallicity, and the potential for phonon-mediated superconductivity. However, confirming superconductivity in borophene experimentally has been evasive to date, mainly due to the detrimental effects of metallic substrates and its susceptibility to oxidation. In this study, we present an ab initio analysis of superconductivity in the experimentally synthesized hydrogenated β12 borophene, which has been proven to be less prone to oxidation. Our findings demonstrate that hydrogenation significantly enhances both the stability and superconducting properties of β12 borophene. Furthermore, we reveal that tensile strain and hole doping, achievable through various experimental methods, significantly enhance the critical temperature, reaching up to 29 K. These findings not only promote further fundamental research on superconducting borophene and its heterostructures, but also position hydrogenated borophene as a versatile platform for low-dimensional superconducting electronics.
... Possessing a rich research history, elemental boron continues to captivate the scientific community with its exceptional and distinctive chemical properties [1,2]. In the first phase of boron exploration, the primary objective was to comprehend the fundamental properties of this lightweight element by scrutinizing its behavior across different dimensionalities, mainly encompassing three-dimensional (3D) clusters, and the prospect of two-dimensional (2D) structures [3][4][5]. ...
We explore the emergence of phonon-mediated superconductivity in bilayer borophenes by controlled intercalation with elements from the groups of alkali, alkaline-earth, and transition metals, using systematic first-principles and Eliashberg calculations. We show that the superconducting properties are primarily governed by the interplay between the out-of-plane (𝑝𝑧) boron states and the partially occupied in-plane (𝑠+𝑝𝑥,𝑦) bonding states at the Fermi level. Our Eliashberg calculations indicate that intercalation with alkaline-earth-metal elements leads to the highest superconducting critical temperatures (𝑇𝑐). Specifically, Be in 𝛿4, Mg in 𝜒3, and Ca in the kagome bilayer borophene demonstrate superior performance with 𝑇𝑐 reaching up to 58 K. Our study therefore reveals that intercalated bilayer borophene phases are not only more resilient to chemical deterioration, but also harbor enhanced 𝑇𝑐 values compared to their monolayer counterparts, underscoring their substantial potential for the development of boron-based two-dimensional superconductors.
... In addition, many phases with exceptional properties, such as hardness and bandgap, could be metastable, such as superhard boron T-50 (T-B 50 ). 4 Thus, computing and constructing the metastable phase diagram would give researchers an estimate of the synthesizability of the metastable phases. ...
... The phases that are reported in this slice are the R3m-B 45 phase, T-B 50 phase, β-phase, Imm2-B7 phase, and Cm-B5 phase, of which only the β-phase was present in the equilibrium phase diagram. It is interesting to note that within a ΔG of just 100 meV/atom, there is a super-hard phase, T-B 50 , 4 suggesting that these phases are realistically synthesizable considering kinetic barriers for transformation. The newly reported phase, Imm2-B7 phase, dominates the phase diagram in the high-pressure regime, while those of T-B 50 , R3m-B 45 , and β-phases occupy regions in the low-pressure regime. ...
Boron, an element of captivating chemical intricacy, has been surrounded by controversies ever since its discovery in 1808. The complexities of boron stem from its unique position between metals and insulators in the Periodic Table. Recent computational studies have shed light on some of the stable boron allotropes. However, the demand for multifunctionality necessitates the need to go beyond the stable phases into the realm of metastability and explore the potentially vast but elusive metastable phases of boron. Traditional search for stable phases of materials has focused on identifying materials with the lowest enthalpy. Here, we introduce a workflow that uses reinforcement learning coupled with decision trees, such as Monte Carlo tree search, to search for stable and metastable boron phases, with enthalpy as the objective. We discover new boron metastable phases and construct a phase diagram that locates their phase space (T, P) at different levels of metastability (ΔG) from the ground state and provides useful information on the domains of relative stability of the various stable and metastable boron phases.
... Possessing a rich research history, elemental boron continues to captivate the scientific community with its exceptional and distinctive chemical properties [1,2]. In the first phase of boron exploration, the primary objective was to comprehend the fundamental properties of this lightweight element by scrutinizing its behavior across different dimensionalities, mainly encompassing three-dimensional (3D) clusters, and the prospect of two-dimensional (2D) structures [3][4][5]. ...
We explore the emergence of phonon-mediated superconductivity in bilayer borophenes by controlled intercalation with elements from the groups of alkali, alkaline-earth, and transition metals, using systematic first-principles and Eliashberg calculations. We show that the superconducting properties are primarily governed by the interplay between the out-of-plane (𝑝𝑧) boron states and the partially occupied in-plane (𝑠+𝑝𝑥,𝑦) bonding states at the Fermi level. Our Eliashberg calculations indicate that intercalation with alkaline-earth-metal elements leads to the highest superconducting critical temperatures (𝑇𝑐). Specifically, Be in 𝛿4, Mg in 𝜒3, and Ca in the kagome bilayer borophene demonstrate superior performance with 𝑇𝑐 reaching up to 58 K. Our study therefore reveals that intercalated bilayer borophene phases are not only more resilient to chemical deterioration, but also harbor enhanced 𝑇𝑐 values compared to their monolayer counterparts, underscoring their substantial potential for the development of boron-based two-dimensional superconductors.
... For B, however, a phase transformation from α-B 12 (Space group No. R 3m) to γ-B 28 (Space group No. Pnnm) occurs at 19 GPa and that from γ-B 28 to α-Ga-type (Space group No. Cmce) occurs at 89 GPa, in accordance with previous studies. 43,44 ThB4 adopts a tetragonal structure with the P4/mbm symmetry under ambient conditions. A conventional cell of the P4/mbm phase contains four formula units (f.u.), ThB4 (Z = 4). ...
With the motivation of searching for new superconductors with better hardness in the Th–B system, we have performed ab initio evolutionary searches for all the stable compounds in this binary system in the pressure range of 0–200 GPa. From our enthalpy of formation calculations, it is found that only ThB4 (Space group No. P4/mbm), ThB6 (Space group No. Pm3¯m), and ThB12 (Space group No. Fm3¯m) compositions are preferred at zero pressure, in accordance with the experimental reports. Under pressure, our calculations predict the thermodynamically stable compositions, ThB (Space group No. R3¯m), Th3B4 (Space group No. R3¯m), ThB2 (Space group No. Amm2), and ThB8 (Space group No. R3¯m) at 54, 19, 35, and 51 GPa, respectively. Furthermore, although the thermodynamical stability of these compounds is predicted to be at high pressures, the possibility of occurrence at 0 GPa due to metastability still exists. The detailed calculations and analysis of the electronic structure and mechanical and thermal properties have been carried out on these materials using the ab initio tool. The P4/mbm phase of ThB4 and the Fm3¯m phase of ThB12 exhibit high hardness of 30.5 and 35.2 GPa under ambient conditions, which is comparable the hard material, B4C. On the other hand, among all the thorium borides, ThB2 shows a high electron–phonon coupling constant of 0.804 and is predicted to have Tc around 12.72 K. In addition, it has been found that the predicted high-pressure compositions, Th3B4 and ThB, display superconductive behavior under pressure. Additionally, various thermophysical quantities such as lattice thermal conductivity, bulk modulus, thermal expansion coefficient, specific heat capacity, and Gibbs free energy under ambient conditions have been determined from these calculations.
... Among them, boron has a number of stable structures owing to its polymorphism [4][5][6]. Theoretical predictions indicate that borophene [6][7][8][9], boron hydride [10], boron sulfide [11], boron oxide [12], and boron phosphide [13] form stable 2D phases; hence, these structures have attracted much attention as targets for developing new 2D materials [14]. Among them, rhombohedral boron monosulfide (r-BS) has been successfully synthesized experimentally [15] and is theoretically predicted to exhibit excellent thermal conductivity [16] and high hydrogen storage performance via alkali modification [17]. ...
Two-dimensional materials have wide ranging applications in electronic devices and catalysts owing to their unique properties. Boron-based compounds, which exhibit a polymorphic nature, are an attractive choice for developing boron-based two-dimensional materials. Among them, rhombohedral boron monosulfide (r-BS) has recently attracted considerable attention owing to its unique layered structure similar to that of transition metal dichalcogenides and a layer-dependent bandgap. However, experimental evidence that clarifies the charge carrier type in the r-BS semiconductor is lacking. In this study, we synthesized r-BS and evaluated its performance as a semiconductor by measuring the Seebeck coefficient and photo-electrochemical responses. The properties unique to p-type semiconductors were observed in both measurements, indicating that the synthesized r-BS is a p-type semiconductor. Moreover, a distinct Fano resonance was observed in Fourier transform infrared absorption spectroscopy, which was ascribed to the Fano resonance between the E(2) (TO) phonon mode and electrons in the band structures of r-BS, indicating that the p-type carrier was intrinsically doped in the synthesized r-BS. These results demonstrate the potential future application prospects of r-BS.
