Simple Borate Research Articles

Luminescent inorganic mixed borate phosphors materials for lighting

The need of new materials with desirable optical properties has become important in recent years. In particular, a need has emerged for compounds having better luminescence properties in various practical applications. The introduction of rare earth ions as activators improves the luminescence properties of the compounds considerably. Boron is one of the most abundant elements in nature. It readily combines with almost all other elements. In combination with oxygen; it forms borates comprised of various anions such as BO3 3- , B2 O5 4- , etc. Apart from these simple borates, several complex compositions exist involving mixed anions as well as double metal borates, due to the three-fold, or four-fold coordination of borate atoms. Borates intrinsically possesses characteristics that are advantageous for optical materials, which include a wide transparency range, large electronic band gap, good thermal and chemical stability, low preparative temperature, optical stability with good nonlinear characteristics, and an exceptionally high optical damage threshold. The unique crystal structure of borates determines their enhanced ultraviolet light transparency, good nonlinearity, and relatively high resistance against laser-induced damage. Some of these complex borates have interesting luminescence properties that are covered in this review. These include double borates containing rare earths RM3 (BO3 )4 , pentaborates LaMgB5 O10 , M3 R2 (BO3 )4 , where M is an alkaline earth, mixed anion borates such as aluminoborate SrAl2 B2 O7 , silicate-borates such as pekovite, SrB2 Si2 O8 , haloborates, M2 B5 O9 X, where M is an alkaline earth and X is a halogen, phosphate borates, and MBPO5 , where M is an alkaline earth. Phosphors based on these compositions find use in various applications such as fluorescence lamps, colour TVs, plasma display panels, high-intensity discharge lamps based on xenon, optically pumped solid-state lasers, eye-safe lasers, and X-ray imaging.

The evolution of the mold flux melt structure during the process of fluorine replacement by B2O3

AbstractThis study presented the melt structure evolution of mold flux during the substitution of fluorine by B2O3, and a computational model for the degree of polymerization (DOP) for borosilicate structure was developed. The results showed that the reduction of fluorine content would promote the replacement of F in [SiF6]‐octahedral unit by the dissociative free oxygen ions (O2−), and release F− ions into the melt to compensate the reduction of F− ions. With the 2 mass% addition of B2O3, the original Si–O–Si bond would be disrupted, and connect with [BO3]‐trihedral to form boroxol ring structure containing [BO2O−]‐trihedral and [BO3]‐trihedral structural units. Then, the Si–O–B bond that [BO3]‐trihedral links [SiO4]‐tetrahedral in boroxol ring was destroyed with the further addition of B2O3, and then the [BO3]‐trihedral could link with the dissociative Q1(Si) and Q0(Si) structural units to transform into [BO4]‐tetrahedral and form a borosilicate long chain. Finally, with 6 mass% addition of B2O3, the borosilicate chain would combine with simple borate and borosilicate structures, and a complex borosilicate structure containing boroxol ring with certain symmetry was formed ultimately. Besides, the calculated result of DOP suggested that the DOP of the melt structure improved during the process of fluorine replacement by B2O3.

Crystallization behavior and structure analysis for molten CaO-SiO2-B2O3 based fluorine-free mold fluxes

An investigation had been conducted to study the effect of CaO/SiO2 mass ratio and B2O3 on the crystallization behavior and the melt structure of fluorine-free mold fluxes. The results showed that the increase of CaO/SiO2 ratio tends to promote the crystallization behavior of the fluorine-free mold flux system, due to the depolymerization of the original complex borosilicate structure by the released free oxygen (O2−) ions with the added CaO. Small amount of B2O3 would initially inhibit the mold flux crystallization, then the further addition would promote crystallization. The melt structure analysis results suggested that with the addition of B2O3 content, the existing silicate structure would connect with each other and also link with the dissociative [BO3]-trihedral units to form borosilicate chain. Simultaneously, O2– could destroy the original diborate structure and form two simple borate structures. Subsequently, the simple borate structure would connect with the dissociative [BO3]-trihedral and the formed borosilicate chain to form a more complex borosilicate structure. Thus, the degree of polymerization of whole molten slag was getting improved, but the overall effect on the mold flux crystallization was depended on the balance between the molten slag structure and viscosity, in which 6 mass% was the critical point in the current mold flux system.

Surface-assembled non-noble metal nanoscale Ni-colloidal thin-films as efficient electrocatalysts for water oxidation.

A highly operative and inexpensive water oxidation scheme using an efficient nanoscale electrocatalyst is vastly demanded for optimum H2 production, CO2 reduction, and has attracted increased attention for chemical energy conversion. We present here a simple route to make efficient electrocatalytic colloidal nanoparticles of nickel out of mere metal ions in a simple borate buffer system. The simple and annealed Ni-colloidal nanoparticles (Ni-CNPs) resulted in a facile transformation into ultrafine films, which further activated the catalysts, while initiating OER just at the overpotential η = 250 mV (1.48 V vs. RHE) under benign conditions. They also showed high porosity and favorable kinetics while displaying impressive Tafel slopes of just 51 mV dec−1, and a high TOF value of 0.79 s−1 at 0.35 V was observed for Ni-CNPs/FTO500. These electrocatalysts also showed long-term stability during the bulk water electrolysis experiment conducted for a continuous 20 hours without notable catalytic degradation, which ensures their economic benefits. The electrochemical data, CVs, kinetic study, short-term durability, extended catalytic stability, SEM analysis, and other supporting data provide compelling evidence that these non-precious, metal-based, electroactive, catalytic, colloidal thin-films (simple and annealed) with nanoscale morphological attributes presented promising catalytic performance under the conditions used herein.

Molecular dynamics study of structural reorganization by electro-thermal poling in sodium diborate glass

This work explores by molecular dynamics simulation the basic mechanisms and pathways that pertain to the induced optical nonlinearity in an ionic oxide glass due to electro-thermal poling. To the best of our knowledge, this is the first time where the kinetics combining the ion migration and the structural rearrangements is studied by using atomistic simulation. Most of the models published so far deal mainly with the charge transport effects, with no information provided on the kinetics of structural reorganization. To this aim, a simple borate glass doped with sodium cations was employed. Notwithstanding the small size of the specimen, due to computer time limitations, we were able to identify most of the experimental trends observed in different glass systems and under different poling conditions and configurations. They include the conversion of negatively charged structural units into neutral ones in the charge depletion region, a process reducing the excess negative charge after the migration of the mobile cations to the cathode, and the increased polymerization of the network close to the anodic surface. Taking into account the restrictions of our model, we also showed a mechanism for the generation of free oxygen species, due to the partial polarization of the Boron-Non-bridging oxygen (B-NBO) bonds along the embedded internal Direct Current (DC) electric field and their subsequent elongation and weakening.

Borate esters as convenient reagents for direct amidation of carboxylic acids and transamidation of primary amides

Simple borates serve as effective promoters for amide bond formation with a variety of carboxylic acids and amines. With trimethyl or tris(2,2,2-trifluoroethyl) borate, amides are obtained in good to excellent yield and high purity after a simple work-up procedure. Tris(2,2,2-trifluoroethyl) borate can also be used for the straightforward conversion of primary amides to secondary amides via transamidation.

Capillary electrophoretic separation of sulphonated anthraquinones in a variety of matrices

Sulphonated anthraquinones are resistant to biodegradation and are, therefore, not eliminated by traditional wastewater treatment plants; this leads to their accumulation in fresh water. To develop new technologies, e.g. phytoremediation, for treatment of such pollutants, a powerful technique is needed for their rapid and inexpensive detection and quantification in any kind of sample. For this purpose capillary electrophoresis seems to be a very promising technique. An efficient, rapid, and inexpensive method has been developed for analysis of five sulphonated anthraquinones, in the 50–950 μm range, with a simple borate buffer. The procedure has been shown to be efficient for all the samples tested, i.e. pure standard solutions, hydroponic media in which plants, bacteria, and algae had grown for 6 weeks, and even plant extracts. This last result is consistent with the idea that phytoremediation could be used as an alternative means of wastewater treatment for these recalcitrant compounds.

A comparative topological analysis of crystal structures of anhydrous simple borates, carbonates and nitrates

A comparative topological analysis of crystal structures of anhydrous simple borates, carbonates and nitrates

Combined DTA and XRD study of sintering steps towards YAl3(BO3)4

Sintering processes in the Y2O3–Al2O3–B2 O3 system and its subsystems (Y2O3–B2O3 and Al2 O3–B2O3) have been investigated by using combined DTA and XRD measurements to get a better understanding of solid state chemical changes resulting in the formation of yttrium aluminum borate (YAl3(BO3)4, YAB) phase and to study the possible role and contribution of various simple borates formed also in the former processes.

Separation of pd(GC) 12 from pd(AT) 12 by free solution capillary electrophoresis

The two synthetic self complementary oligonucleotides pd(AT) 12 and pd(GC) 12 were separated by free solution capillary electrophoresis (CZE) using simple borate buffers. The effects of pH (7.5–9) and the concentration of the buffer (0.03–0.35 M) were investigated. Higher pH values and buffer concentrations led to better resolution and longer migration times, the pH having a more pronounced effect on the separation than the concentration of the buffer. It is proposed that the conformation and effective length of the oligonucleotides may have a role in their separation in free solution capillary electrophoresis.

Capillary Electrophoresis with Laser-Induced Fluorescence Detection for the Analysis of Free and Immune-Complexed Green Fluorescent Protein

Naturally fluorescing green fluorescent protein (GFP) was separated by capillary electrophoresis (CE) and detected by laser-induced fluorescence (LIF). Exploiting recombinant technology and the natural fluorescence of GFP presents the capability of preempting the need for fluorescent derivatization. Such an approach would circumvent the obstacles typically associated with covalently labeling and purifying analytes that undergo fluorescent labeling. The unique property of GFP to fluoresce naturally was combined with CE-LIF to compare GFP isoforms prepared recombinantly orin vitrowith wild-type GFP isoforms isolated from native jellyfishAequorea victoria.Second, GFP antisera were reacted with wild-type GFP and the formation of the GFP antigen–antibody complex was monitored. A simple borate buffer, pH 8.5, was ample for resolving the two isoforms of the naturally fluorescent GFP in less than 5 min. The separation of GFP from GFP–Ab was complete in less than 7 min with the individual components detectable at the picogram level. A number of factors influence CE separation and/or LIF detection including sample buffer pH and incorporation of the additive 1,4-diamino butane. Remarkably, conditions that severely impair fluorescence detection of free GFP do not diminish fluorescence detection of the GFP antigen–antibody complex in a similar manner. Thus, the antibody appears to preserve the natural fluorophore of GFP. These data lend credence to the utility of coupling naturally fluorescent GFP to the speed, automation, and reduced sample size benefits of CE-LIF analysis for efficient separation and detection of an immunoreaction. In principle, a fusion protein of antibody with GFP as the label in CE-based immunoassays offers an advantageous alternative to the fluor-labeling process usually required in LIF detection.

Application of micellar electrokinetic chromatography to the quality control of pharmaceutical formulations: the analysis of xanthine derivatives.

Micellar electrokinetic chromatography (MEKC) has been applied to the analysis of three different drugs. Although belonging to different therapeutic classes, all these drugs contain xanthine derivatives as active substances. Pentoxifylline was separated from eight related xanthines. Quantitative MEKC was applied to determine impurities (caffeine and xanthine) in the purified drug at the 0.05-0.1% level and also for the determination of the active substance in Agapurin tablets. Ethofylline and theophylline were separated from ephedrine and mebrophenhydramine and determined in Xantedrylettae tablets while caffeine was separated from mephenhydramine and determined in Kinedryl tablets. In all cases, simple borate buffers with sodium dodecyl sulfate as the surfactant were satisfactory and little separation optimization was required. The relative standard deviation (RSD) of the migration times was better than 1% while the RSD of the observed areas was better than 2%. This demonstrates that MEKC is a valuable alternative for the traditional high-performance liquid chromatography analysis of drugs and drug formulations.

ChemInform Abstract: Hydrated Double Borates and Corresponding Simple Borates

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Osmotic and Activity Coefficients of Some Simple Borate Solutions at the Freezing Point

Activity coefficients for aqueous sodium and potassium tetraborate, sodium metaborate, sodium and potassium fluoroborate, and orthoboric acid were derived from their freezing points. The measurements confirmed in general the behavior of these salts at 25° except that the tetraborates showed different low concentration behavior from that predicted from isopiestic data. Because of this difference, the 25° activity coefficients reported earlier for sodium and potassium tetraborates have been revised. The new values for 0.15 m solutions of the tetraborates are 0.345 at 25° and 0.303 at the freezing point.

Changes caused by electron irradiation in the microhardness of simple borate glasses

Changes caused by electron irradiation in the microhardness of simple borate glasses

Osmotic and activity coefficients of some simple borates in aqueous solution at 25°

Activity coefficients for sodium tetraborate, potassium tetraborate, sodium metaborate, sodium fluoroborate, and orthoboric acid were derived from isopiestic vapor pressure measurements. The osmotic behavior of sodium tetraborate, at concentrations up to its solubility limit, was the same as that of the more soluble potassium salt. The mean activity coefficients of both tetraborates were quite low: 0.355 at 0.1 m; the activity coefficients of sodium metaborate and fluoroborate were less than those of sodium chloride, indicating partial association in solution.The boric acid results were not very reliable because boric acid apparently volatilized during the measurements, but the results obtained indicated that it behaves like a non-electrolyte at all concentrations up to saturation, with an activity coefficient never less than 0.92.

Immiscibility and Surface Tension of Some Simple Borates

This paper reports the minimum concentrations of second cations that must be added to phase‐separated binary borates to produce single‐phase glasses when batches of approximately 100 gm. are melted at 1300°C. and poured into an 8‐ by 10.5‐cm. steel mold at room temperature. Surface tensions are also reported for the melts at 900°, 1000°, 1100°, 1200°, and 1300°C. Alkali and alkaline‐earth cations and Pb++, Cd++, and Al+++ were used as auxiliary cations to make single phased the phase‐separated binary borates of the principal cations Ba++, Sr++, Ca++, Cd++, Zn++, and Mg++. Within any group of the periodic table the minimum homogenizing concentration increases with decreasing ionic radius of either the auxiliary or the principal cation. The surface tensions of layered binary melts are independent of cation identity and content, indicating an upper layer of nearly pure B2O3. For layered or unlayered ternary melts containing alkali auxiliary cations, surface tension increases with increasing cation content at rates that decrease with the ionic radius of either cation, indicating that in these layered ternary melts the cations enter the upper (B2O3‐rich) layer more freely than in the corresponding binary melts.