Trivalent Bismuth Research Articles

Influence of substitution on dielectric and impedance spectroscopy of Sr 1 − xBi 2 + yNb 2O 9 ferroelectric ceramics synthesized by chemical route

Nanocrystalline powders of Sr 1 − x Bi 2 + y Nb 2O 9 (SBN, x = 0.0, 0.1, 0.2, 0.3, and 0.4; y = 0, 0.066, 0.133, 0.200, and 0.266) were prepared by aqueous solution method using water-soluble Sr–EDTA, Bi–EDTA and Nb–tartarate as the starting materials. XRD showed that the samples were free from fluorite or pyrochlore phase within heat-treatment temperature from 550 to 600 °C. Average crystallite size and particle diameter were observed to be between 10 and 25 nm, which were analyzed through XRD and TEM, respectively. Bi-substitution has substantially improved the sinterability of SBN and enabled to achieve high density (96%), which was otherwise difficult in the case of pure SBN. The dielectric properties of SBN ceramics were significantly enhanced by the partial replacement of Sr 2+ ions by the trivalent bismuth ions. The complex impedance diagrams of Bi-substituted SBN, x = 0.4 ceramics exhibited only one semicircle indicating a significant contribution from the grains. In contrast, the impedance plots for pure and other substituted SBN ceramics show an additional low-frequency semicircle, which was attributed to the blocker size effects. The dielectric behavior of pure and Bi-substituted SBN ceramics was rationalized using the impedance and modulus data.

Synthesis, Structural Characterization, and Cation Transport of Tripotassium Pentabismuth Arsenate K3Bi5(AsO4)6

During the exploration of the K2O-Bi2O 3 -As2O5 system, single crystals of a new arsenate of trivalent bismuth, K3Bi5(AsO4) 6, were isolated by solid state reaction at 600°C. The title compound crystallizes in the monoclinic system, space group C2/c (N°15) with a = 18.257(2) Å, b = 7.260(1) Å, c = 20.130(4) Å, β = 119.86(1)°, and Z = 4. Its structure consists of a three-dimensional framework made up of AsO4 tetrahedra and BiO6 and BiO7 polyhedra sharing edges and corners, delimiting cavities wherein K+ ions reside. This compound exhibits a potassium ion conductivity but with rather low conductivity value.

Bi 3+ luminescence in ABiO 2Cl (A=Sr, Ba) and BaBiO 2Br

Trivalent bismuth luminescence is reported in three Sillen bismuth oxyhalide phases, SrBiO 2Cl, BaBiO 2Cl, and BaBiO 2Br. These compounds exhibit Bi 6s6p→6s 2 emission under UV and X-ray radiations. At room temperature, BaBiO 2Cl shows the most intense light emission, with spectral and decay properties similar to those found in Bi 4Ge 3O 12 (BGO). At low temperatures, each phase show an increase in the photoluminescence intensities and a narrowing of the emission peaks. In contrast to the temperature dependence of BGO, X-ray excited luminescence intensities of all three phases remain relatively constant throughout the temperature range 10–295 K, though much lower than BGO at low temperatures. This result indicates that the Sillen phases undergo less thermal quenching than BGO. The low temperature and room temperature radio-luminescence decay times were determined from pulsed X-ray measurements. At room temperature, SrBiO 2Cl exhibits faster decays than BGO, while BaBiO 2Cl and BaBiO 2Br have decay times similar to BGO.

Synthesis, characterization and thermal decomposition of thiourea complexes of antimony and bismuth triiodide

The thiourea complexes of antimony and bismuth triiodide were synthesized by a direct reaction of antimony and bismuth triiodide with thiourea powder at room temperature. The formula of the complex is MI3[SC(NH2)2]3(M=Sb, Bi). The crystal structure of the complexes belongs to monoclinic system and the lattice parameters are a=1.4772 nm, b=1.6582 nm, c=2.0674 nm and β=90.81° for SbI3(SC(NH2)2)3 and a=1.4009 nm, b=2.0170 nm, c=2.0397 nm and β=90.84° for BiI3[SC(NH2)2]3. The infrared spectra reveal that the trivalent antimony or bismuth ion is coordinated by the nitrogen atom, not the sulfur atom of the thiourea. Thermal analysis shows that there are two times structure rearrangements or phase transformation in the complexes from 100 to 170°C.

A Novel Effect of Bismuth Ions: SELECTIVE INHIBITION OF THE BIOLOGICAL ACTIVITY OF GLYCINE-EXTENDED GASTRIN

Although bismuth salts have been used for over two centuries for the treatment of various gastrointestinal disorders, the mechanism of their therapeutic action remains controversial. Because gastrins bind two trivalent ferric ions with high affinity, and because ferric ions are essential for the biological activity of glycine-extended gastrin 17, we have investigated the hypothesis that trivalent bismuth ions influence the biological activity of gastrins. Binding of bismuth ions to gastrins was measured by fluorescence quenching and NMR spectroscopy. The effects of bismuth ions on gastrin-stimulated biological activities were measured in inositol phosphate, cell proliferation, and cell migration assays. Fluorescence quenching experiments indicated that both glycine-extended and amidated gastrin 17 bound two bismuth ions. The NMR spectral changes observed on addition of bismuth ions revealed that Glu-7 acted as a ligand at the first bismuth ion binding site. In the presence of bismuth ions the ability of glycine-extended gastrin 17 to stimulate inositol phosphate production, cell proliferation, and cell migration was markedly reduced. In contrast, bismuth ions had little effect on the affinity of the CCK-2 receptor for amidated gastrin 17, or on the stimulation of inositol phosphate production by amidated gastrin 17. We conclude that bismuth ions may act, at least in part, by blocking the effects of glycine-extended gastrin 17 on cell proliferation and cell migration in the gastrointestinal tract. This is the first report of a specific inhibitory effect of bismuth ions on the action of a gastrointestinal hormone.

Solubility Properties of Hydroxyapatite Doped with Divalent and Trivalent Ions

ABSTRACTHydroxyapatite (HA) is a bone-like ceramic with good cytocompatibility properties and, consequently, has been used as coatings for dental and orthopedic implants. However, the main limitation of using HA as a coating material is its high calcium dissolution rate. The present study investigated an assortment of dopants in order to lower the calcium dissolution rate of HA. The HA dopants used in the present study were divalent (magnesium and zinc) and trivalent (yttrium, lanthanum, indium, and bismuth) cations. In a 21 day study, undoped HA and HA doped with magnesium (Mg), lanthanum (La), and bismuth (Bi) were found to increase in mass while formulations doped with zinc (Zn), indium (In), and yttrium (Y) were found to decrease in mass. Decreased mass may be due to loss of a number of chemical groups (such as calcium, phosphorous, and hydroxyl groups). Studies were also performed to specifically evaluate calcium dissolution. The divalent and trivalent-doped HA averaged samples had calcium concentrations in the supernatant consistently below the undoped HA samples suggesting lower calcium dissolution rate for all doped formulations. The results of the present study demonstrated that of those dopants tested that increased in mass, HA doped with Bi had the lowest amount of calcium released into the supernatant media. Since calcium has been shown to increase adsorption of proteins important for new bone growth, the present study provided evidence that to decrease the calcium dissolution rate of HA, dopants should be used, particularly Bi.

Enhanced Cytocompatibility Properties of Hydroxyapatite Doped with Trivalent Ions

ABSTRACTHydroxyapatite (HA) is a bone-like ceramic used as a coating for dental and orthopedic implants. It is well known for its good cytocompatibility properties, but is limited in use due to its high solubility within the body and mechanical properties that differ from surrounding tissue and bone. The present in vitro study investigated a variety of dopants as a way to further enhance the good cytocompatibility properties of HA as well as address these problematic properties. The dopants investigated were divalent (magnesium and zinc) and trivalent (yttrium, lanthanum, indium, and bismuth) ions. Of the trivalent ions, yttrium and indium have smaller ionic radii than calcium. The present study showed osteoblast adhesion to be statistically greater (p < 0.1) on yttrium-doped HA and indium-doped HA than on undoped HA. Since yttrium and indium are both trivalent ions of a smaller ionic radius than calcium, and other ions of different size and charge did not show significant changes in osteoblast adhesion, these results suggest that substituting divalent calcium with a trivalent ion of smaller size encourages osteoblast adhesion.

Preparation of New Bismuth Oxides by Hydrothermal Reaction

ABSTRACTHydrothermal reactions using NaBiO3·nH2O produced a variety of newbismuth oxides that were not prepared by high temperature reaction. Some of them have pentavalent bismuth such as Bi2O4O, LiBiO3, ABi2O6 (A = Mg, Zn) and AgBiO3. When using transition metal or rare-earth metal solutions, new bismuth oxides with trivalent bismuth were obtained. In the case of Cr(NO3)3 solution a chromium bismuth oxyhydroxide, HBi3(CrO4)2O3, was prepared at 180°C, while in A2CrO4 (A = Li, Na, K) solution a new bismuth chromium oxide, Bi8(CrO4)O11, was prepared above 180°C. When A2MoO4 (A = Li, Na, K) solution was used, a new phase appeared above 220°C. By using A2WO4 (A = Li, Na, K) solution β-Bi2O3 and Bi2WO6 were obtained above 220°C.

Ranitidine bismuth citrate in the treatment of Helicobacter pylori infection and duodenal ulcer.

To review the clinical pharmacology of ranitidine bismuth citrate in the treatment of Helicobacter pylori (HP) infection and duodenal ulcer. A MEDLINE search of the English-language literature from 1992 to January 1997 was conducting using the key terms Tritec, ranitidine, and bismuth. References of articles pertaining to treatment of duodenal ulcer or HP were extensively searched for relevant sources. All articles pertaining to ranitidine bismuth citrate were considered for inclusion, with emphasis placed on randomized, double-blind trials. Priority was placed on data pertaining to regimens that are currently approved by the Food and Drug Administration for the treatment of duodenal ulcer in conjunction with HP. Each tablet of ranitidine bismuth citrate 400 mg contains 162 mg of ranitidine base, 128 mg of trivalent bismuth, and 110 mg of citrate. It uses the acid-suppressive actions of ranitidine and the antimicrobial and mucosal protective effects of bismuth to eradicate HP. Ranitidine bismuth citrate in conjunction with clarithromycin represents one of four treatment regimens currently approved in the US for duodenal ulcer associated with HP infection. In four double-blind, randomized trials, this agent has achieved HP eradication rates of 73-94% and duodenal ulcer healing rates of 73-89%. It is given twice daily for 28 days, and is associated with very low rates of adverse effects. Relative to some therapeutic alternatives, ranitidine bismuth citrate plus clarithromycin may be simpler to take and have less adverse effects, but may be more expensive. Compared with omeprazole plus clarithromycin, it is less expensive, may have lower ulcer healing rates, but may be more effective in eradicating HP. The role of ranitidine bismuth citrate will continue to evolve as more patients are treated, and other regimens continue to be tested for duodenal ulcer healing and HP eradication.

Synthesis and characterization of (Bi, AE)MnO 3 (AE=Ca, Sr) system

The effects of electron lone pairs of trivalent bismuth ions on the crystal structure and magnetic properties were examined in Bi 1− x AE x MnO 3 (AE=Ca, Sr). Polycrystalline perovskite manganites Bi 1− x AE x MnO 3 were synthesized by using a conventional ceramic technique and a high-pressure technique (4 GPa). Perovskites with triclinic, monoclinic, and tetragonal distortions were found in Bi 1− x Sr x MnO 3 from X-ray powder diffraction. In particular superlattice reflections were found in BiMnO 3 by electron diffraction which revealed two kinds of unit cell, i.e. polymorphism. The bismuth lone pair character was reflected in these structures. Both Bi 1− x Ca x MnO 3 and La 1− x Ca x MnO 3 showed the same crystal symmetry and weak ferromagnetism in the Ca-rich region. However, the magnetic moment of Bi 1− x Ca x MnO 3 was larger than that of La 1− x Ca x MnO 3 with the same x value. Their ferromagnetism was suppressed by charge ordering with further substitution of trivalent cations, although the charge ordering temperature of the La-system is higher than that of the Bi system. The difference is probably associated with the Bi lone pair.

Bismuth hematoxylin staining of nucleic acids

Hematoxylin is readily oxidized to the blue pigment hematein. Hematein can complex with a wide variety of metal salts or mordants to form mordant dyes. These dyes stain various components of animal tissues. The component stained depends on the metal in the mordant dye.Alum hematoxylin uses trivalent aluminum ion as a mordant. At extreme dilution, requiring long staining times, alum hematoxylin is a specific stain for nucleic acids. As usually used, alum hematoxylin stains nucleoproteins, staining them nearly as well after the removal of the nucleic acids as before.Bismuth shows a high affinity for nucleic acids. Although all common bismuth salts are insoluble in water, sodium bismuthate reacts with an aqueous solution of hematoxylin to produce hematein and trivalent bismuth ions. The bismuth ions complex with the hematein to form a water-soluble “bismuth hematoxylin.” HEPES (N-[2-hydroxyethyl]piperazine- N'-2-ethanesulfonic acid), 8 mg/ml of solution, greatly increases the amount of bismuth hematoxylin formed. Glycerol, 1/8 v/v, improves the stability of the complex.

Experimental Investigation on Edge Inversion at Trivalent Bismuth and Antimony: Great Acceleration by Intra- and Intermolecular Nucleophilic Coordination

Experimental Investigation on Edge Inversion at Trivalent Bismuth and Antimony: Great Acceleration by Intra- and Intermolecular Nucleophilic Coordination

The luminescence of filled s-shell ions in hexavalent tellurium compounds

The possibilities of and the restrictions on the luminescence of materials based on tellurates activated with divalent lead and trivalent bismuth are reported and discussed. Photoionization influences the spectral characteristics of luminescent materials and may be detrimental to the thermal quenching temperature.

Zur lumineszenz von biaktiviertem yttriumorthoborat

Powder materials of yttriumorthoborate coactivated by trivalent bismuth and gadolinium or praseodymium and gadolinium described here have been prepared by solid state reaction. These luminophors crystallize in the vaterite type. Therefore they have a pseudo-hexagonal structure. There are two crystallographically different sites for the cations. In addition to X-ray diffractograms, emission and excitation spectra and spectra of the diffuse reflection of the luminophors have been studied at room temperature along with the influence of temperature and UV radiation on emission of the samples. Bi III and Pr III ions sensitize Gd III luminescence. There is only Gd III luminescence in the emission spectra. The peak of maximum intensity is at 31 888 cm −1. Therefore the luminophors could be used in medicine for therapeutical purposes.

Investigations of Defect Centres in Alkali Halides Doped with Trivalent Cations. Part 1: Bismuth in NaCl, KCl and RbCl Crystals

A correlated set of experiments was performed with a view to study the effect of trivalent bismuth upon some properties of NaCl, KCI and RbCI crystals. For NaCI the effect of BiO+ ions was also investigated. It was stated that: 1. The hydrolytic properties of bismuth are responsible for the formation of BiO+ centres also in crystals doped with BP+ ions. 2. During all experiments performed, the dopant remains in the form of trivalent cations. 3. Optical absorption spectra of bismuth are similar to those characteristic of other heavy metal ions with the s 2 electronic configuration. 4. The charge excess of BP+ ions is compensated by cation vacancies whereas for BiO+ ions the preferential bonding between Iii and O 2— serves for the charge compensation.

Increased biliary excretion of glutathione is generated by the glutathione-dependent hepatobiliary transport of antimony and bismuth

We have recently demonstrated that the hepatobiliary transport of arsenic is glutathione-dependent and is associated with a profound increase in biliary excretion of glutathione (GSH), hepatic GSH depletion and diminished GSH conjugation (Gyurasics Á, Varga F and Gregus Z, Biochem Pharmacol 41: 937–944 and Gyurasics Á, Varga F and Gregus Z, Biochem Pharmacol 42: 465–468, 1991). The present studies in rats aimed to determine whether antimony and bismuth, other metalloids in group Va of the periodic table, also possess similar properties. Antimony potassium tartrate (25–100 μmol/kg, i.v.) and bismuth ammonium citrate (50–200 μmol/kg, i.v.) increased up to 50- and 4-fold, respectively, the biliary excretion of non-protein thiols (NPSH). This resulted mainly from increased hepatobiliary transport of GSH as suggested by a close parallelism in the biliary excretion of NPSH and GSH after antimony or bismuth administration. Within 2 hr, rats excreted into bile 55 and 3% of the dose of antimony (50 μmol/kg, i.v.) and bismuth (150 μmol/kg, i.v.), respectively. The time courses of the biliary excretion of these metalloids and NPSH or GSH were strikingly similar suggesting co-ordinate hepatobiliary transport of the metalloids and GSH. However, at the peak of their excretion, each molecule of antimony or bismuth resulted in a co-transport of approximately three molecules of GSH. Diethyl maleate, indocyanine green and sulfobromophthalein (BSP), which decreased biliary excretion of GSH, significantly diminished excretion of antimony and bismuth into bile indicating that hepatobiliary transport of these metalloids is GSH-dependent. Administration of antimony, but not bismuth, decreased hepatic GSH level by 30% and reduced the GSH conjugation and biliary excretion of BSP. These studies demonstrate that the hepatobiliary transport of trivalent antimony and bismuth is GSH-dependent similarly to the hepatobiliary transport of trivalent arsenic. Proportionally to their biliary excretion rates, these metalloids generate increased biliary excretion of GSH probably because they are transported from liver to bile as unstable GSH complexes. The significant loss of hepatic GSH into bile as induced by arsenic or antimony may compromise conjugation of xenobiotics with GSH.

Synthesis and crystal structure of intramolecularly coordinated organobismuth compounds and edge inversion at trivalent bismuth

Synthesis and crystal structure of intramolecularly coordinated organobismuth compounds and edge inversion at trivalent bismuth

Reaction of dicymanthrenylphenylbismuth with cupric chloride

A synthesis is reported for dicymanthrenylphenylbismuth which is the first representative of cymanthrenyl derivatives of trivalent bismuth. The reaction of this compound with CuCl2 leads to the loss of the phenyl and cymanthrenyl ligands from the central bismuth atom.

Synthesis and structure of some interesting oxides of bismuth

Synthesis and structures of several new oxides containing bismuth are described. Three types of structures are common among the multinary oxides containing trivalent bismuth. They are the sillenite structure of γ-Bi2O3, the layered perovskite structure of Aurivillius phases and the pyrochlore structure. The influence of Bi3+∶6s 2 lone pair electrons is seen in all the three structures. In transition metal oxides containing trivalent bismuth,d o cations (Ti4+, Nb5+, W6+) stabilize the layered perovskite structure, while cations containing partially-filledd orbitals (V4+, Cr3+, Fe3+) favour pyrochlore-related structures. Ferroelectric distortion ofMO6 octahedra of thed o cations seems to play an important role in stabilizing layered perovskite structures.

Relative stabilities of layered perovskite and pyrochlore structures in transition metal oxides containing trivalent bismuth

In order to investigate the factors determining the relative stabilities of layered perovskite and pyrochlore structures of transition metal oxides containing trivalent bismuth, several ternary and quaternary oxides have been investigated. While d 0 cations stabilize the layered perovskite structure, cations containing partially-filled d orbitals (which suppress ferroelectric distortion of MO 6 octahedra) seem to favor pyrochlore-related structures. Thus, the vanadium analogue of the layered perovskite Bi 4Ti 3O 12 cannot be prepared; instead the composition consists of a mixture of pyrochlore-type Bi 1.33V 2O 6, Bi 2O 3, and Bi metal. The distortion of Bi 1.33V 2O 6 to orthorhombic symmetry is probably due to an ordering of anion vacancies in the pyrochlore structure. None of the other pyrochlores investigated, Bi 2NbCrO 7, Bi 2NbFeO 7, TlBiM 2O 7 ( M = Nb, Ta), shows evidence for cation ordering in the X-Ray diffraction patterns, as indeed established by structure refinement of TlBiNb 2O 7.