Showing papers on "Bismuth published in 1989"
TL;DR: Bismuth encephalopathy occurred in France as an epidemic of toxicity and was associated with the intake of inorganic salts including bismuth subnitrate, subcarbonate and subgallate and the use of dimercaprol as an antidote has produced reports of both positive and negative findings.
Abstract: Inorganic bismuth salts are poorly soluble in water: solubility is influenced by the acidity of the medium and the presence of certain compounds with (hydr)oxy or sulfhydryl groups. The analysis of bismuth in biological material is not standardised and is subject to large variation; it is difficult to compare data from different studies, and older data should be approached with caution.
228 citations
TL;DR: In this article, the effect of bismuth adatoms adsorbed irreversibly on Pt (100) is investigated both for the direct electrocatalytic oxidation of formic acid and for the reaction of formation of the stable poisoning intermediate.
162 citations
106 citations
TL;DR: In this paper, a new family of double-sheet copper oxide compounds with BiO or TIO bilayers was described, which can improve our understanding of the relationship between Tc and the CuO2 sheets.
Abstract: ONE of the main families of oxide superconductors comprises compounds with varying numbers of CuO2 sheets sandwiched between BiO or TIO bilayers1–5. The superconducting transition temperature (Tc) in these compounds increases with the number of CuO2 sheets; for example, Tc is 80–108 K for the double-sheet 2212 phase, and 110–125 K for the triple-sheet 2223 phase. Here we describe a new family of double-sheet copper oxide compounds with BiO or TIO bilayers, which can improve our understanding of the relationship between Tc and the CuO2 sheets. The new compounds, Bi2Sr2(Ln1–xCex)2Cu2O10+y, and Tl2Ba2(Ln1–xCex)2Cu2O10+y (where Ln is Sm, Eu or Gd), have double CuO2 pyramidal sheets between double BiO or TIO layered units, like the 2212 phase, but with a different arrangement of adjacent CuO2 sheets. The new bismuth compounds (Bi-2222) have a significantly lower Tc (∼30 K or less) than the 2212 or 2223 phases, even when the charge-carrier (hole) concentrations are comparable. So far, we have not found superconductivity in the Tl-2222 compounds.
94 citations
TL;DR: Samples of La2−xBixCuO4 were prepared by codecomposition of the nitrates in air Single-phase products were obtained for x ≦ 1 0 The substitution of bismuth for lanthanum resulted in an increase in delocalization of holes, as indicated by increased conductivity and a decrease in Neel temperature as discussed by the authors.
87 citations
TL;DR: In this paper, the conversion of red phosphorus to white phosphorus and the growth of black phosphorus single crystals from the solution of white phosphorus in liquid bismuth were performed in an evacuated quartz-glass apparatus without breaking the vacuum.
Abstract: Needle-shaped and film- or plate-shaped black phosphorus single crystals were prepared by an improved bismuth-flux method. The conversion of red phosphorus to white phosphorus and the growth of black phosphorus single crystals from the solution of white phosphorus in liquid bismuth were performed in an evacuated quartz-glass apparatus without breaking the vacuum. Needle crystals measured about 5 mm in length and 10 to 100 µm in thickness. The thickness of film or plate crystals ranged from 1 to 10 µm and the width was usually above 100 µm, generally increasing with decreasing thickness. Some crystal morphologies were observed and analyzed crystallographically.
87 citations
TL;DR: In this paper, it was shown that surface defects deliberately created on the surface like randomly distributed steps are the preferential place for the dissolution of the adsorbed bismuth, and a general view of the different ways of interchanging the various surface structures, SI, SII or SnIII, was given.
82 citations
TL;DR: In this article, the phase change, densification, and microstructure development of ZnO doped with both Bi2O3 and Sb2O7 were studied to better understand the sintering behavior of znO varistors, which is related to the formation of pyrochlore and liquid phases; the densification is retarded by the former and promoted by the latter.
Abstract: The phase change, densification, and microstructure development of ZnO doped with both Bi2O3 and Sb2O3 are studied to better understand the sintering behavior of ZnO varistors. The densification behavior is related to the formation of pyrochlore and liquid phases; the densification is retarded by the former and promoted by the latter. The pyrochlore phase, whose composition is Bi3/2ZnSb3/2O7, appears below 700°C. The formation temperature of the liquid phase depends on the Sb/Bi ratio: about 750°C for Sb/Bi 1 by the reaction of the pyrochlore phase with ZnO. Hence, the densification rate is determined virtually by the Sb/Bi ratio and not by the total amount of additives. The microstructure depends on the sintering temperature. Sintering at 1000°C forms intragrain pyrochlore particles in ZnO grains as well as intergranular layers, but the intragrain particles disappear at 1200°C by the increased amount of liquid phase, which enhances the mobility of the solid second phase.
79 citations
TL;DR: In this article, a saturation value of 1.4 monolayer bismuth enrichment was established on the grain boundaries in the 400-700°C temperature range at a rate which increased with temperature.
71 citations
TL;DR: In this paper, the structure of the AO(m)M2Ca(n-1)Cu(n)O(2n+2) family with m = 1 and 2 is studied for n = 1, 2, and 3.
Abstract: The structures of the AO(m)M2Ca(n-1)Cu(n)O(2n+2) family with m = 1 and 2 are studied for n = 1, 2, and 3. The ease with which these structures intergrow with each other is demonstrated. One structural feature peculiar to all the copper oxide superconductors is that the part of the structure between the nonconsecutive CuO/sub 2/ sheets is ill defined. 29 references.
70 citations
TL;DR: In this paper, the average valencies of copper and bismuth in the superconducting Bi-Sr-Ca-Cu-O system have been determined using a coulometric titration technique.
Abstract: The average valencies of copper and bismuth in the superconducting Bi-Sr-Ca-Cu-O system have been determined using a coulometric titration technique. Both copper(III) and bismuth(V) were allowed to react with an excess of copper(I) and the excess of copper(I) was then back-titrated by an anodic oxidation. Bismuth(V) was determined alone by taking advantage of the reaction with manganese(II). In the Bi-Sr-Ca-Cu-O sample having a high transition temperature (Tc) of 90 K, the average valencies of copper and bismuth were found to be 2.144 and 3.119, respectively, using these techniques.
TL;DR: In this article, the authors compared X-ray structural data, evolution overpotentials, and rate constants for anodic oxidation of Mn(II) and 2-thiophene carboxylic acid (2-TCA) at Bi-doped in.
Abstract: X‐ray structural data, evolution overpotentials , and rate constants are compared for anodic oxidation of Mn(II) and 2‐thiophene carboxylic acid (2‐TCA) at Bi‐doped in . It is concluded that the rutile structure of pure deposited anodically from containing Pb(II) is retained even as the Bi(III) content is increased to , i.e., mole fraction . There is no evidence of a new oxide phase being formed. Crystallites of the are deposited with an increasing preferential orientation of the 020‐plane parallel to the Au substrate surface as the ratio Bi/Pb is increased. Increasing values of and decreasing values of appear to be correlated with the increased preferential orientation. However, change in preferential orientation is concluded not to be the primary determining factor in the electrocatalytic phenomena. The kinetic results are discussed also on the basis of the so‐called "volcano plot" of as a function of the enthalpy of transition between the two highest oxide phases for metal oxide electrodes.
TL;DR: In this paper, solution pyrolysis of Bi(S2CNRR′)3 in p-xylene or chloroform on a glass substrate at 350 °C under Ar atmosphere gave polycrystalline and low resistive (102 Ω cm in dark) bismuth sulfide thin films which showed large photoelectric effect.
Abstract: Solution pyrolysis of Bi(S2CNRR′)3 in p-xylene or chloroform on a glass substrate at 350 °C under Ar atmosphere gave polycrystalline and low resistive (102 Ω cm in dark) bismuth sulfide thin films which showed large photoelectric effect.
TL;DR: The distribution of the bismuth atoms over the cation sites in the 2212 Bi-Sr-Ca-Cu-O superconductor has been determined by anomalous scattering synchrotron crystallography, and the view that neither extra oxygen nor overlap of thebismuth 6p and copper 3d bands is needed to account for the holes is supported.
Abstract: The distribution of the bismuth atoms over the cation sites in the 2212 Bi-Sr-Ca-Cu-O superconductor has been determined by anomalous scattering synchrotron crystallography. The analysis of reflection pairs measured at wavelengths of 0.9243 and 0.9600 angstrom shows a delocalization of the bismuth atoms over the calcium and strontium sites. The "mixed" plane between the CuO 2 layers contains 6.0(1.4) percent bismuth (where the number in brackets represents the statistical standard deviation derived from the least-squares refinement of the data), and a much smaller amount of strontium than often assumed. The strontium deficiency is charge-compensated by the creation of electron holes in the CuO 2 layer. The result supports the view that neither extra oxygen nor overlap of the bismuth 6 p and copper 3 d bands is needed to account for the holes, which are an essential feature of the superconductivity mechanism.
TL;DR: This article showed that even simple casting of such a melt and annealing in the form of solid blocks results in the formation of practically single-phase Bi 2 Sr 2 CaCu 2 O 8 + x.
TL;DR: This article reviews the pertinent literature on the reported adverse reactions to bismuth compounds to provide the necessary background to assess the value of bismUTH subcitrate and bism Ruth subsalicylate as therapeutic compounds.
Abstract: Bismuth compounds, in particular bismuth subsalicylate and colloidal bismuth subcitrate, are now being actively promoted for the treatment of diarrhoea and peptic ulcer disease. The past history of the therapeutic use of bismuth compounds has been marred by episodes of serious adverse reactions. Salicylism is a possible complication with bismuth subsalicylate. This article reviews the pertinent literature on the reported adverse reactions to bismuth compounds to provide the necessary background to assess the value of bismuth subcitrate and bismuth subsalicylate as therapeutic compounds.
TL;DR: BiCl3 reacts with three equivalents of NaOR (R = CMe3, C6H3Me2-2,6) to form Bi(OR)3, which was found by X-ray crystallography to have distorted pyramidal geometry as discussed by the authors.
Abstract: BiCl3 reacts with three equivalents of NaOR (R = CMe3, C6H3Me2-2,6) to form Bi(OR)3, which for R = C6H3Me2-2,6 was found by X-ray crystallography to have distorted pyramidal geometry.
TL;DR: In this paper, lead and bismuth(III) complexes of nota, dota, and teta were synthesized and their kinetic properties were investigated to show that the dota complexes are the most inert over the pH range 4-12 and 1-10.
Abstract: Lead(II) and bismuth(III) complexes of nota, dota, and teta were synthesized and their kinetic properties were investigated to show that the dota complexes are the most inert over the pH range 4–12 and 1–10 for lead and bismuth, respectively.
TL;DR: The calculated velocity dispersion and electromechanical coupling factors for plate modes in representative piezoelectric materials are described and frequency dependence of velocity and electromechanical coupling factors are given.
Abstract: Recent theoretical studies and experiments have been shown that interdigital transducers can couple strongly to plate modes in piezoelectric materials and in piezoelectric-on-nonpiezoelectric composite membranes. The calculated velocity dispersion and electromechanical coupling factors for plate modes in representative piezoelectric materials are described. The frequency dependence of velocity and electromechanical coupling factors are given, under different metallization conditions, for generalized stiffened-Lamb, pure stiffened-Lamb, and stiffened-shear (shear-horizontal) modes, for various plate orientations in lithium niobate, lithium tantalate, quartz, bismuth germanium oxide, and zinc oxide. For lithium niobate, electromechanical-coupling values as high as 15% are found under narrowband bandpass conditions, and 5% under wideband low-pass conditions. For lithium tantalate, bismuth germanium oxide, coupling values of 0.5, 2, and 4% are obtained. For quartz with its weaker piezoelectricity, the coupling is still made smaller. >
TL;DR: In this article, the lifetime of Bi(III)-doped PbO{sub 2} film electrodes is discussed as a function of concentration, rotation speed, analyte, and applied voltage.
Abstract: Heterogeneous rate constants for the anodic oxidation of many inorganic and organic compounds at electrolytically deposited beta-PbO{sub 2} film electrodes in 1.0M HClO{sub 4} are increased by doping the oxide with Bi(III). The rate constants at the mixed-oxide electrode rise sharply for a change from 0 to 10 mole percent (m/o) Bi(III) in the electrodeposition solution, and reach a mass transport-limited value for some compounds at 40 m/o Bi(III). Results of kinetic, voltammetric, and spectroscopic studies of these electrodes are described. In addition, the lifetime of Bi(III)-doped PbO{sub 2} film electrodes is discussed as a function of concentration, rotation speed, analyte, and applied voltage.
TL;DR: In this article, the a.c. conductivity σ ac (ω), is found to be proportional to ω s in the low temperature region suggesting the validity of the tunneling model as reported in Part I.
TL;DR: In this paper, the power law dependencies of the sensor conductivity versus concentration and the response time versus concentration were investigated for bismuth iron molybdate catalysts with gold wire contacts.
TL;DR: In this paper, the influence of each dopant on the electrical behavior of ZnO in a system which is more simple and chemically purer in comparison with commercial varistors was investigated.
Abstract: ZnO has been doped with various oxides, mainly bismuth, cobalt, and manganese oxides. The aim of the present approach is to look at the influence of each dopant on the electrical behavior of ZnO in a system which is more simple and chemically purer in comparison with commercial varistors. It appears that cobalt or manganese additions do not substantially modify the bulk conductivity of ZnO. Also these dopants by themselves do not lead to a varistor effect when the material is subjected to a potential sweep. On the other hand, bismuth‐based compositions behave like varistors. The best performances have been recorded for a simultaneous doping with manganese and bismuth.
TL;DR: In this article, the oxalate precipitation approach has been used to synthesize superconductive BiSrCaCuO materials, which are characterized by electrical resistivity and ac-susceptibility measurements.
Abstract: The oxalate precipitation approach has been used to synthesize superconductive BiSrCaCuO materials. By computer modelling of the chemical equilibria, we have studied the operational criteria for the oxalate precipitation and thus established a laboratory routine. The coprecipitated oxalate samples are found to be X-ray amorphous. Microstructural studies using scanning electron microscopy equipped with an energy dispersive X-ray analyzer reveal submicron size particles of the oxalate coprecipitates with high chemical homogeneity. The sintered oxides are characterized by electrical resistivity and ac-susceptibility measurements. The superconducting properties of these oxalate-route samples are found to be comparable, if not superior, to those observed for samples produced by other conventional methods.
TL;DR: The reaction between BiCl3 and 3 equivalents of Li[NPh2] in THF solution affords the bismuth amide complex, [Bi(NPh 2)3], which has been characterized by X-ray crystallography as discussed by the authors.
TL;DR: In this article, the authors presented data for the hydride generation atomic absorption spectrometric determination of arsenic, antimony, bismuth and selenium in stream sediments and a certified reference material.
Abstract: Data are presented for the hydride generation atomic absorption spectrometric determination of arsenic, antimony, bismuth and selenium in stream sediments and a certified reference material (CPB-1 Lead Concentrate) using six different extraction media, viz., hydrochloric acid; nitric acid; 7 M nitric acid; nitric acidsulphuric acid (9 + 1); aqua regia; and reversed aqua regia (HNO3+ HCl, 3 + 1). Extraction with 7 M nitric acid was performed in test-tubes placed in a drilled out heating block (110 °C, 3.5 h). All other extractions were carried out overnight in 50-ml calibrated flasks placed in a water-bath. Bismuth was extracted quantitatively by all the extraction media. Arsenic and selenium were extracted completely by each of the media used, except for hydrochloric acid. Antimony was extracted completely by only two of the media, viz., aqua regia and reversed aqua regia. Selenium is converted to the +4 oxidation state on extraction with aqua regia and reversed aqua regia, i.e., selenium(VI) is reduced to selenium(IV), and the lower oxidation states are oxidised to selenium(IV). Hence the extracts can be analysed for selenium without pre-reduction to selenium(IV), which is necessary for hydride generation atomic absorption spectrometry. The nitric acid-hydrochloric acid mixtures used bring arsenic, antimony, bismuth and selenium quantitatively into solution and are, therefore, suitable for the sequential or simultaneous determination of these elements in a single sample solution. The speciation of selenium in stream sediments and surface waters is discussed.
TL;DR: In this paper, a new bismuth-iron oxide, isostructural with the 2223 superconductor, was obtained, and electron diffraction study showed the existence of satellites, similar to those observed in the superconducting bistuth cuprates.
TL;DR: In this paper, the ionization potentials of Sb4n clusters are studied as a function of the size and the observed evolution confirms the nonmetallic character of their structure, and the possible metastable character of the Sb 4n structure is discussed and illustrated by experiments performed as the function of inert gas temperature in the clusters source.
Abstract: Antimony clusters are produced by the gas aggregation method. They are found to be built from Sb4 units. The Sb+4n clusters are demonstrated to relax their excess energy by evaporation of a tetramer and the binding energy of Sb4 in the cluster is measured to be about 1.3 eV, well below the binding energy of a Sb atom in the bulk (≊2.75 eV). The ionization potentials of Sb4n clusters are studied as a function of the size and the observed evolution confirms the nonmetallic character of their structure. These results are compared with those obtained for bismuth clusters which exhibit a very different behavior. Finally the possible metastable character of Sb4n structure is discussed and illustrated by experiments performed as a function of inert gas temperature in the clusters source.
TL;DR: In this paper, an evolving factor analysis was used to estimate the concentration profiles and spectra of Bi3+ and BiC12+ through BiCl formed by injection of bismuth perchlorate into a flowing stream of 1·0 mol 1−1 HCl.
Abstract: Evolving factor analysis is used to estimate the concentration profiles and spectra of Bi3+ and the bismuth chloride complexes BiC12+ through BiCl formed by injection of bismuth perchlorate into a flowing stream of 1·0 mol 1−1 HCl. The estimated spectra compare favorably with previously published spectra of the complexes.