Bismuth Atoms Research Articles

Electrical conduction and optical characteristics of Li2O and Bi2O3 Co-doped zinc-phosphate glassy nanocomposites: A critical observation of mixed ionic electronic effect

In the present report, the combined effects of the co-doping of metal oxide (Bi2O3) and Lithium oxide (Li2O) into the glassy matrix with chemical composition xLi2O-(0.45-x)Bi2O3-(0.15ZnO-0.40P2O5) (x = 0.05, 0.15, 025, and 0.35 mol%) are investigated thoroughly. The FESEM and X-ray diffraction data affirm the crystalline nature of the studied glassy composites. The obtained band gap energy values are declined from (3.68–3.17) eV, while the Urbach energy values are declined from (0.38–0.27) eV. Moreover, the mechanism responsible for AC conductivity has been analyzed using Almond–West formalism and Jonscher's universal power law. The observed rise in both AC and DC conductivity in the glass samples is attributed to the mixed ionic electronic effect. In the ionic diffusion model, an increased defect site concentration improves Li+ ion migration through percolation channels. The reduction in both electrostatic binding energy and strain energy lowers the Anderson-Stuart activation energy, facilitating Li+ ion migration and enhancing conductivity. Additionally, in the small polaron hopping model, an increase in the density of defect states suggests more defect sites that facilitate electronic hopping, creating deep localized states and transitions between localized and extended states. Replacing a Bismuth atom with a Lithium atom increases the number of non-bridging oxygen, enhancing the conduction band tail, reducing the energy needed for hopping conductivity, and increasing conductivity.

Negative and persistent photoconductivity in Bi-doped Pb0.5Sn0.5Te epitaxial films

This work presents the investigation of the photoconductivity effect in undoped and doped Pb0.5Sn0.5Te epitaxial films, with bismuth (Bi) atoms, at temperatures of 80 and 300 K. The results indicate that the samples show negative photoconductivity effect (NPC) and persistent photoconductivity (PPC). A detailed study was performed on Pb0.5Sn0.5Te sample doped with 0.15 % Bi, which presented higher photoconductivity amplitude than the other samples, by performing Hall effect and photoconductivity measurements in the temperature range of 80–300 K under dark and illuminated conditions. Using Arrhenius model, trap activation energy was extracted and compared with energies found in literature. From the Hall measurement we found that the NPC effect observed is due to a decrease in the mobility when the sample is illuminated while the carrier concentrations are nearly unaltered. It was also found that Pb0.5Sn0.5Te:Bi presented photoconductivity response for a wide range of wavelengths, indicating that it is potentially interesting for application in optic sensor devices.

Strongly bound anions featuring bismuth fluoride building blocks

The stability of polynuclear superhalogen anions composed of BiF5 building blocks was investigated using ab initio electronic structure methods and flexible basis sets. A comprehensive exploration of the ground state potential energy surfaces of (Bi2F11)−, (Bi3F16)− and (Bi4F21)− anions, which can be viewed as comprising BiF5 fragments and an additional fluorine atom, led to the identification of their isomeric structures. It was found that the most stable isomers, predicted to dominate at room temperature, correspond to chain-like extended structures containing BiF6 subunits, with fluorine ligands arranged octahedrally around Bi atoms, sharing F atoms to form Bi–F–Bi bridging linkages. The vertical electron detachment energies of the (BinF5n+1)− anions (n = 1–4) were found to be very high (ranging from 10.91 to 13.36 eV) and increased with the number of bismuth atoms (n) and thus the BiF5 building blocks involved in the structure. Thermodynamic stability of the (BinF5n+1)− anions (i.e., their susceptibility to fragmentation) was also verified and discussed.

Enhancing the thermoelectric performance of BiGa2X4 (X=S, Se) P-type semiconductors by optimizing charge carrier concentration or chemical potentials

We present an extensive analysis of the structural, electronic, optical, elastic, and thermoelectric properties of BiGa2X4 compounds, where X represents either sulfur (S) or selenium (Se). Our approach employed the all-electron full potential linearized augmented plane wave (FP-LAPW) technique, offering a comprehensive understanding of these materials' characteristics. The calculated lattice constants (a), the unit cell height (c), and the c/a ratio closely match experimental data, affirming the accuracy of our calculations. A pivotal focus of our study was on the electronic properties, including the indirect bandgaps (A→M−Γ) and (M→A). We found that BiGa2S4 exhibited an indirect bandgap (Eg) of 2.504 eV, while BiGa2Se4 possessed a slightly lower value of 1.878 eV. This variation was primarily attributed to the intricate interactions among bismuth, sulfur, and selenium atoms, particularly involving p−p orbital interactions. Additionally, we explored the optical characteristics of these compounds, determining their maximum absorption wavelengths. BiGa2S4 exhibited an absorption peak at 4.476 eV, whereas BiGa2Se4 displayed a slightly lower maximum absorption at 3.741 eV. Moreover, BiGa2Se4 showcases a higher dielectric constant, which augments its potential for optoelectronic applications. A critical aspect of our research is the assessment of the elastic properties, elucidating that both compounds exhibited fragility and anisotropy. We observed that at 300 K, the lattice thermal conductivity (kL) for BiGa2S4 and BiGa2Se4 was measured at 1.57W/mK and 1.14W/mK, respectively, indicating low thermal conductivity. At 1000 K, both BiGa2S4, and BiGa2Se4 exhibit significant ZT values of 0.8389 and 0.8722, respectively. The ZT values of the p-type semiconductors are notably higher than those of the n-type. At T = 900 K, the optimized ZT values for BiGa2S4, and BiGa2Se4 are found to be 0.82909 and 0.90548, respectively. Achieving these values requires either increasing the concentration of charge carriers to n = 0.11715 x 1022 cm−3 for BiGa2S4 and n = 0.0812 x 1022 cm−3 for BiGa2Se4, or reducing the chemical potentials by 0.40151 Ryd and 0.38001 Ryd, respectively.

Systematic investigation on the rational design and optimization of bi-based metal oxide semiconductors in photocatalytic applications

To address the global energy shortage and mitigate greenhouse gas emissions on a massive scale, it is critical to explore novel and efficient photocatalysts for the utilization of renewable resources. Bi-based metal oxide (Bi x MO y ) semiconductors composed of bismuth, transition metal, and oxygen atoms have demonstrated improved photocatalytic activity and product selectivity. The vast number of element combinations available for Bi x MO y materials provides a huge compositional space for the rational design and isolation of promising photocatalysts for specific applications. In this study, we have systematically investigated the electronic and optical properties over Bi2O3 and a series of selected Bi x MO y group materials (BiVO4, BiFeO3, BiCoO3, and BiCrO3) by calculating band structure, basic optical property features, mobility and separation of charge carriers. It is clearly noted that the band gap and band edge position of the Bi x MO y group materials can be tuned in a wide range in comparison to Bi2O3. Similarly, the light response of Bi x MO y also can be broadened from the ultraviolet to the visible light region by adjusting the selection of transition metals. Additionally, the analysis of the effective mass of charge carriers of these materials further confirms their possibility in photocatalytic reaction applications because of the appropriate separation efficiency and mobility of carriers. A selection of experimental investigations on the crystal structure, composition, and optical properties of Bi2O3, BiVO4, and BiFeO3 as well as their catalytic performance in the degradation of methylene blue over was also conducted, which agree well with the theoretical predictions.

Surface-Enriched Room-Temperature Liquid Bismuth for Catalytic CO2 Reduction.

Bismuth-based electrocatalysts are effective for carbon dioxide (CO2) reduction to formate. However, at room temperature, these materials are only available in solid state, which inevitably suffers from surface deactivation, declining current densities, and Faradaic efficiencies. Here, the formation of a liquid bismuth catalyst on the liquid gallium surface at ambient conditions is shown as its exceptional performance in the electrochemical reduction of CO2 (i.e., CO2RR). By doping a trace amount of bismuth (740ppm atomic) in gallium liquid metal, a surface enrichment of bismuth by over 400 times (30 at%) in liquid state is obtained without atomic aggregation, achieving 98% Faradic efficiency for CO2 conversion to formate over 80 h. Ab initio molecular simulations and density functional theory calculations reveal that bismuth atoms in the liquid state are the most energetically favorable sites for the CO2RR intermediates, superior to solid Bi-sites, as well as joint GaBi-sites. This study opens an avenue for fabricating high-performing liquid-state metallic catalysts that cannot be reached by elementary metals under electrocatalytic conditions.

Signal oscillations in helium scattering by bismuth atoms in the low energy range

Low Energy Ion Scattering (LEIS) analysis of bismuth selenide (Bi2Se3), a strong 3D topological insulator, revealed oscillations of the detected signal in dependence on primary ion beam energy. Bismuth is a part of the group of elements where oscillatory behaviour was already noticed, such as gallium, indium, or lead. Generally, it is ascribed to quasi-resonant charge exchange processes between primary ion and target atom. Moreover, clear differences exist between data for target atoms in elemental form and for atoms in compound form. A study of Bi signal yields in different material forms was performed for primary He+ projectiles within the energy range from 0.50 to 6.00 keV. A foil of pure Bi, Bi2Se3, Bi2O3 and thin Bi films deposited on several substrates (SiO2, CuOx) by Molecular Beam Epitaxy were analysed. The energy shift in the position of oscillations was observed when the oxygen atoms were present at the surface and bonded to Bi atoms. A description of the Bi ion yield variation is provided to facilitate the quantification process in LEIS.

Analysis of high-energy radiation shielding features of SeTeSn glass after incorporation of bismuth

The main goal of this study is to evaluate how well several quaternary Chalcogenide Glasses (ChGs) shield against extremely intense radiation, such as X-rays and gamma rays. The ChGs under investigation are part of the quaternary glass system SeTeSnBi. By using the Phy-X/PSD program, it was possible to determine some important safety factors. We were specifically able to compute the linear/mass attenuation coefficients thanks to this software. Interestingly, we discover that these values are higher than those of several traditional and commercially available glasses, suggesting better-shielding characteristics. In addition, we investigated numerous important shielding characteristics, such as the removal cross-section, mean free path, transmission factor, half-value layer, and radiation protection efficacy. Furthermore, estimates have been made for the mechanical properties, such as the bulk modulus, shear modulus, longitudinal modulus, and Poisson's ratio. Examining the effects of substituting Bismuth atoms for Selenium atoms on the shielding capabilities of the original SeTeSn glass was a crucial component of our study. These thorough examinations offer insightful information on the possible uses of these quaternary ChGs as cutting-edge radiation shielding materials.

Electrocatalytic membrane with p-block bismuth atoms for selective oxygen activation to hydroxyl radicals for effective water decontamination

Herein, individual p-block bismuth (Bi) atoms are dispersed onto N-doped Ti3C2Tx MXene (BiN3/MXene) to enhance the 3e− oxygen reduction reaction (ORR), for the electrosynthesis of hydroxyl radicals (HO•) via the activation of molecular oxygen (O2). Theoretical calculations and experiments reveal that the p-orbitals of Bi atoms can readily hybridize with the p-orbitals of O, which enables the transfer of charges, creates sufficient strength of adsorption for oxygen intermediates, lowers the activation energy, and modulates the rate-limiting reaction. The optimized generation of HO• is up to 26.7 μmol/(L·h·cm2) without additional chemical reagents, facilitating efficient removal of micropollutants from complex water matrices. Specifically, the rate constant (kobs) for sulfamethoxazole degradation achieves 1.027 min−1, outperforming the reported processes for micropollutants removal. This work illuminates the atomic-level construction of a p-block BiN3/MXene electrocatalytic membrane to efficiently perform the 3e− ORR and highlights the substantial potential for wastewater decontamination.

Localizing bismuth single atoms around tin nanoparticles for efficient CO2 reduction and fabrication of high-performance sodium-ion batteries

The utilization of Bi/Sn alloy-based materials has garnered significant interest as a promising avenue for the development of sodium-ion batteries and the achievement of electrocatalytic CO2 reduction. This is due to their notable attributes of high theoretical specific capacity and low working potential, as well as their abundance and high catalytic activity. Nevertheless, the practical application potential of these alloys is restrained by their inadequate electrical conductivity without incorporating conductive carbon networks to improve the electrical conductivity of the composite material and consequential volumetric fluctuations, which ultimately lead to unsatisfactory cycle life and the depletion of active components. A single-atom Bi-coated Sn nanoparticle was synthesized utilizing metal-organic framework (MOF) compounds as precursors. The resulting composite exhibits the ability to mitigate volume changes that arise during charge and discharge processes, while also enhancing the catalytic activity of the system for CO2 reduction through synergistic effects. Upon pyrolysis of the MOFs at elevated temperatures, a carbon matrix "protective layer" is formed to prevent the loss of active substances under conditions of electrode pulverization. This leads to improved cycle stability and coulomb efficiency of the battery. The ion permeation and gas diffusion are facilitated by the three-dimensional porous structures of composites. The conductive networks further improve the conductivity of materials, prevent the shedding of electrode material from electrodes, and facilitate electron transport. Consequently, the electrode demonstrates exceptional electrochemical performance, as evidenced by a high capacity of 510 mAh g−1 after 1000 cycles and a reversible capacity of 497 mAh g−1 after 500 cycles. Furthermore, the composite material demonstrates a notable degree of selectivity towards CO2 reduction, as evidenced by a coulombic efficiency of 95.7% for HCOOH at a potential of −1.1 V but only a coulombic efficiency of 2.3% for H2. Furthermore, the composite material exhibits commendable stability. The findings presented in this study offer valuable technical insights towards the attainment of carbon neutrality and carbon peaking.

Electronic, optical, and thermoelectric characteristics of (Ae)xFBiS2 (Ae=Sr, Ba, and x=1.7) layered materials useful in optical modulator devices

The recent discovery of superconductivity behavior in the mother BiS2-layered compounds has captivated the attention of several physicists. The crystal structure of superconductors with alternate layers of BiS2 is homologous to that of cuprates and Fe-based superconductors. The full-potential linearized augmented plane-wave (FP-LAPW) technique was utilized to investigate the electronic structures and density of states in the vicinity of the Fermi energy of SrFBiS2 and BaFBiS2 compounds under the electron carriers doping. The introduction of electron doping (carries doping) reveals that the host compounds SrFBiS2 and BaFBiS2 exhibit features indicative of superconductivity. This carrier doping of SrFBiS2 and BaFBiS2 compounds (electron-doped) has a significant impact on the lowest conduction states near the Fermi level for the emergence of the superconducting aspect. The electron doping modifies and induces changes in the electronic structures with superconducting behavior in (Ae)1.7FBiS2(Ae=Sr,Ba) compounds. A Fermi surface nesting occurred under the modification of electrons (carriers) doping in the host compounds SrFBiS2 and BaFBiS2. Furthermore, the optical characteristics of the carrier-doped SrFBiS2 and BaFBiS2 compounds are simulated. Due to the anisotropic behavior, the optical properties of these materials based on BiS2 demonstrate a pronounced polarization dependency. The starting point at zero photon energy in the infrared region is elucidated by considering the Drude features in the optical conductivity spectra of SrFBiS2 and BaFBiS2 compounds, when the electron carriers doping is applied. It was clearly noticed that the spin-orbit coupling (SOC) influences the electronic band structures, density of states, Femi surface, and optical features because of the heavy Bismuth atom, which may disclose fascinating aspects. Further, we conducted simulations to assess the thermoelectric properties of these mother compounds. The two BiS2-layered compounds could be suitable for practical thermoelectric purposes and are highlighted through assessment of electrical conductivity, thermal conductivity, Seebeck coefficient, and power factor. As a result, we propose that the mechanisms of superconducting behavior in BiS2 family may pave new avenues for investigating the field of unconventional superconductivity. It may also provide new insights into the origin of high-Tc superconductivity nature.

Cyclic Hydrocarbon Frameworks Containing Two Bismuth Atoms: Towards 9,10-Dibismaanthracene.

When bismuth atoms are incorporated into cyclic organic systems, this commonly goes along with strained or distorted molecular geometries, which can be exploited to modulate the physical and chemical properties of these compounds. In six-membered heterocycles, bismuth atoms are often accompanied by oxygen, sulfur or nitrogen as a second hetero-element. In this work, we present the first examples of six-membered rings, in which two CH units are replaced by BiX moieties (X=Cl, Br, I), resulting in dihydro-anthracene analogs. Their behavior in chemically reversible reduction reactions is explored, aiming at the generation of dibisma-anthracene (bismanthrene). Heterometallic compounds (Bi/Fe, Bi/Mn) are introduced as potential bismanthrene surrogates, as supported by bismanthrene-transfer to selenium. Analytical techniques used to investigate the reported compounds include NMR spectroscopy, high-resolution mass spectrometry, single-crystal X-ray diffraction analyses, and DFT calculations.

Синтез и строение гидрата бис(2,4-диметилбензолсульфоната) трифенилвисмута

The interaction of triphenylbismuth with 2,4-dimethylbenzenesulfonic acid in diethyl ether in the presence of tert-butyl hydroperoxide have synthesized triphenylbismuth bis(2,4-dimethylbenzenesulfonate) hydrate. The X-ray diffraction pattern has been obtained at 293 K on an automatic diffractometer D8 Quest Bruker (MoKα-radiation, λ = 0.71073 Å, graphite mono-chromator) of crystals 1 [C34H34O6,5S2Bi, M 819.71, monoclinic syngony, symmetry group C2/c; cell parameters: a = 34.948(16) Å, b = 9.210(5) Å, c = 21.114(9) Å, α = γ = 90.00 degrees, β = 99.97(2) degrees; V = 6693(6) Å3; the crystal size is 0.38 × 0.14 × 0.06 mm; intervals of reflection indexes are –45 ≤ h ≤ 45, –11 ≤ k ≤ 11, –27 ≤ l ≤ 27; total reflections 52257; independent reflections 7691; GOOF 1.026; R1 = 0.0325, wR2 = 0.0776; residual electron density is 0.98/–0.82 e/Å3] the bismuth atom have a distorted trigonal-bipyramidal coordination. The OBiO axial angles are 171.58(12) degrees; the sum of the CBiC angles in the equatorial plane is 360 degrees. The lengths of the Bi–O axial bonds are 2.274(3) Å and 2.284(3) Å; The range of changes in the lengths of the Bi–C equatorial bonds is 2.188(5)–2.209(4) Å. The structure of triphenylbismuth bis(2,4-dimethylbenzenesulfonate) hy-drate contains intramolecular contacts between the bismuth and oxygen atoms of the sulfonate lig-ands; the Bi···O=S distances are 3.178(10) and 3.261(10) Å, which is less than the sum of the Van der Waals radii of bismuth and oxygen (3.59 Å). A water molecule is connected by a hydrogen bond O–H···O=S 2.50 Å with the oxygen atom of the sulfonate ligands. Complete tables of atomic coordinates, bond lengths, and bond angles for the structures were deposited at the Cambridge Crystallographic Data Center (no. 1919942, deposit@ccdc.cam.ac.uk, http://www.ccdc.cam.ac.uk).

In-situ reconstruction of Bi60In2O93 nanotube for stable electroreduction of CO2 at ampere-current densities

We report a unique Bi-In nanotube catalyst (Bi60In2 NT), which was prepared by in-situ reconstruction of a novel precursor of Bi60In2O93. By virtue of the structural characteristics of hollow nanotubes and the modulated electronic structure by indium atom doping, Bi60In2 NT delivers an impressive partial current density of 1.03 A cm−2 with a high Faradaic efficiency (FE) of 95.3% for formate production. Moreover, Bi60In2 NT demonstrates a long-term stability of 48 h at a high current density of 1 A cm−2 in MEA cells. In-situ ATR-SEIRAS spectra confirm that doping of indium atoms enhances the adsorption strength of Bi sites to the *OCHO intermediate. Additionally, DFT calculations reveal that the charge redistribution between bismuth and indium atoms promotes the adsorption of *CO2 intermediates and accelerates the charge transfer kinetics, which undoubtedly contributes to the enhanced activity.

Kagome-like BiP3 Monolayer: An Emerging Quasi-Direct Auxetic Semiconductor Coupled with High Anisotropic Mobility toward Visible-Light-Driven Photoelectrocatalytic pH-Robust Overall Water-Splitting.

Two-dimensional (2D) Janus materials exhibit an outstanding potential that can meet the rigorous requirements of photocatalytic water splitting resulting from their unique atomic arrangement. However, these materials are quite scarce. Through ab initio density functional theory calculations, we introduce a kagome topology into the honeycomb lattice of blue phosphorene using phosphorus and bismuth atoms to build a hybrid honeycomb-like kagome lattice, realized by a hitherto unknown kagome-like Janus-like BiP3 monolayer with robust stability. Excitingly, the out-of-plane asymmetry benefiting from kagome and honeycomb topologies gives rise to a significantly negative out-of-plane Poisson's ratio and an obvious built-in electric field pointing from the sublayer of the P atom to the sublayer of the Bi atom. In conjunction with the investigations that encompass semiconducting properties, such as a quasi-direct gap, suitable band-edge positions, effective visible-light absorption, and high carrier mobility, the BiP3 monolayer achieves overall water splitting at pH 0-14 regardless of strain. Moreover, this intrinsic electric field provides a sufficient photogenerated carrier driving force for water splitting. The bare BiP3 comprises P and Bi atoms that function as catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) active sites, respectively. Upon exposure to light, the reaction of water into H2 and O2 can be observed across a pH range of 0-14. Meanwhile, by designing a transition-metal single-atom catalyst (TM@BiP3), our investigations have shown that embedding a single TM on BiP3 is a feasible route to improving the HER/OER activity by reducing the overpotentials to -0.039 and 0.58 eV for Mo and Os atoms, respectively. In this case, the positive value of the external potential acts as a sufficient OER driving force, i.e., in the light environment, the Os@BiP3 system can promote water molecules spontaneously oxidized into O2 at pH 0-14.

A Dibismuthane with Olefin Functional Groups: Towards Tridentate Hybrid Chalcogen/Olefin Ligands

AbstractBis[dibenzobismepine], a dibismuthane composed of two bismepine units (R2Bi−BiR2), was synthesized and fully characterized (R2=(C6H4CH)2). Reactions of this dibismuthane with diphenyl dichalcogenides, dibenzoylperoxide, and elemental chalcogens have been investigated. All products of these reactions have been isolated and fully characterized, including a series of compounds R2Bi−E−BiR2 (E=O−Te). These species contain two olefin units of the bismepine moieties and a chalcogen atom as potential coordination sites. The potential of these species to act as hybrid tridentate chalcogen/olefin ligands with bismuth atoms as structure‐determining elements in the backbone has been investigated by theoretical approaches, aiming at the complexation of CoI, RhI, IrI and Ni0, Pd0, Pt0. The analytical techniques applied in this work include heteronuclear and 2D NMR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction analysis, and DFT calculations.

A potential dilute magnetic semiconductor: Lead-free Cs2AgBi1-xFexBr6 double perovskite

The demand for the increase of information storage density and manipulation speed boosts the intense development of new magnetic materials. Among them, dilute magnetic semiconductors are considered to be promising candidates. Here, we present the doping-induced ferromagnetism in lead-free Cs2AgBiBr6 double perovskite through partly replacing the bismuth atoms with iron, and systematically investigate the influence of doping concentration on the optical and magnetic properties of the crystals. With the increase of iron concentration, the crystal converts from diamagnetism to weak ferromagnetism. Specifically, the one with the highest iron concentration of 1.92% shows magnetic response during the entire temperature region between 3 and 300 K and an effective magnetic moment of 0.46 μB. The EPR measurement confirms the magnetic isolated state of Fe3+ in the host lattice at room temperature. This work offers a new strategy for the construction of magnetized double perovskites, which is a potential new kind of DMS for the further application of lead-free halide perovskites in the spintronics.

Triplet bismuthinidenes featuring unprecedented giant and positive zero field splittings.

Isolation of triplet pnictinidenes, which bear two unpaired electrons at the pnictogen centers, has long been a great challenge due to their intrinsic high reactivity. Herein, we report the syntheses and characterizations of two bismuthinidenes MsFluindtBu-Bi (3) and MsFluind*-Bi (4) stabilized by sterically encumbered hydrindacene ligands. They were facilely prepared through reductions of the corresponding dichloride precursors with 2 molar equivalents of potassium graphite. The structural analyses revealed that 3 and 4 contain a one-coordinate bismuth atom supported by a Bi-C single σ bond. As a consequence, the remaining two Bi 6p orbitals are nearly degenerate, and 3 and 4 possess triplet ground states. Experimental characterizations with multinuclear magnetic resonance, magnetometry and near infrared spectroscopy coupled to wavefunction based ab initio calculations concurred to evidence that there exist giant and positive zero field splittings (>4300cm-1) in their S=1 ground states. Hence even at room temperature the systems almost exclusively populate the lowest-energy nonmagnetic Ms=0 level, which renders them seemingly diamagnetic.

A study on solubility of bismuth cations in nickel cobalt ferrite nanoparticles and their influence on dielectric and magnetic properties

In this work, a low temperature (∼600 °C) solution combustion technique is employed for the synthesis of Ni0.5Co0.5BixFe2-xO4 (NCBFO, where x = 0.0, 0.05, 0.1, 0.15, & 0.2) nanoparticles with crystallite size variation of 17–22 nm. The X-ray diffraction (XRD) technique is used to confirm the formation of cubic spinel phase of Bi3+ doped (for x ≤ 0.05 samples) nickel–cobalt ferrite (NCFO) nanoparticles. The increase in bismuth substitution (x > 0.05) results in the formation of the Bi2O3 along with the NCFO structure, which results in the reduction of binding energy and is confirmed by the XRD and X-ray photoelectron spectroscopy (XPS) techniques. From the Raman spectra, the change in the intensities of the peaks is observed due to the variation of Bi3+ in NCFO matrix. Due to increasing cation concentration and electronegativity, the FTIR absorption band shifts toward the lower wave numbers. Dielectric measurements were carried out to examine the charge transport behavior and electric conduction mechanism. The FESEM images shows the non-magnetic bismuth atoms are diffused into the NCFO nanoparticles. From the vibrating sample magnetometer (VSM) analysis, it is observed that saturation magnetization, remanent magnetization, coercivity and squareness ratio are found to be maximum for x = 0.15 NCBFO sample. The high coercivity (Hc = 916.8 Oe) for the x = 0.15 sample indicates the hard ferromagnetic behaviour of the samples.

Cationic Bismuth Amides Add across Activated C═X Bonds (X = C, N, and S): Pronounced Solvent Effects on Reactivity and Selectivity

The reactivity of a literature-known, ring-strained cationic bismuth amide toward the unsaturated substrates RN═C═NR, CS2, and acrylonitrile is reported (R = iPr, Cy, and pTol). Subtle changes in the polarity of the reaction medium (THF vs pyridine) can be exploited to selectively address two different reaction pathways. Either the dinuclear nature of the starting material is preserved, only one substrate molecule per two bismuth atoms is incorporated into the product, and an aryl migration is possible or well-defined mononuclear compounds with a Bi/substrate ration of 1:1 are observed. These findings correlate with an unexpected increase in reactivity of the cationic bismuth species, when the polarity of the solvent is increased from THF to pyridine, and are likely to be connected to the nuclearity of the cationic bismuth amide starting material.