Showing papers on "Antimony published in 1991"
104 citations
TL;DR: A novel open antimony sulfide framework of composition – Sb3S5– has been synthesized hydrothermally, in the presence of tetramethyl ammonium ions, and determination of the crystal structure demonstrates that the (Me4N)+ molecules occlude a system of intersecting channels at 90� to one another.
Abstract: A novel open antimony sulfide framework of composition [Sb(3)S(5)](-) has been synthesized hydrothermally, in the presence of tetramethyl ammonium ions. Determination of the crystal structure demonstrates that the (Me(4)N)(+) molecules (Me, methyl) occlude a system of intersecting channels at 90 degrees to one another. The three-dimensional framework is assembled from a new building unit, flat s-shaped buckled sheets of edge-linked 4-rings containing Sb(2)S(2) moieties. These are cross-linked in two directions to form the system of channels.
100 citations
TL;DR: In this article, a method for simultaneous determination of As(III)+Sb(III) and Sb (III+V+Sb+V) was developed that uses selective hydride generation, liquid nitrogen cooled trapping, and gas chromatography/photoionization detection.
Abstract: A method for the simultaneous determination of As(III)+Sb(III) and As(III+V)+Sb(III+V) has been developed that uses selective hydride generation, liquid nitrogen cooled trapping, and gas chromatography/photoionization detection. The detection limit for arsenic is 10 pmol/L, while that for antimony is 3.3 pmol/L; precision (as relative standard deviation) for both elements is better than 3%
83 citations
71 citations
01 Jan 1991
TL;DR: Water samples from the 1988 Black Sea Expedition were analyzed for dissolved, inorganic arsenic and antimony speciation, and methylarsonic, methylstibonic, dimethylarsinic and dimethylstibinic acids were found in the deep anoxic water.
Abstract: Water samples from the 1988 Black Sea Expedition were analysed for dissolved, inorganic arsenic and antimony speciation, and methylarsonic, methylstibonic, dimethylarsinic and dimethylstibinic acids. Inorganic arsenic was depleted in surface waters, increased rapidly with depth in the oxic water column, and then decreased in the anoxic waters. In oxygenated waters arsenate [As(V)] was the predominant species, while arsenite [As(III)] was the major form near the sulfide interface. Both arsenate and arsenite were found in the deep anoxic water. In contrast to arsenic, inorganic antimony displayed highest concentrations at the surface, decreased to the sulfide interface, and increased in the deeper anoxic water column. The speciation of antimony was dominated by Sb(V) in oxygenated waters, Sb(III) near the sulfide interface, and Sb(III) and (V) in the deep anoxic zone. Inorganic arsenic and antimony displayed apparent removal just above the sediment-water interface. The methylated arsenic and antimony acids were only detected in surface waters. These data demonstrate that arsenic and antimony are controlled by both biological and redox reactions. Like phosphate, arsenic appears to be linked with the cycling of organic matter in surface waters. However, at and below the sulfide interface their behaviors diverge. Antimony and phosphate are linked only by their apparent participation in the cycling of metal oxides near the sulfide interface. The abundance of thermodynamically unstable As(V) and Sb(V) in the deep anoxic waters of the Black Sea can be attributed primarily to the delivery of the pentavalent ions via detrital fluxes and the formation of deep waters, with subsequent slow rates of reduction.
67 citations
TL;DR: In this paper, the thermal stability and the thermal degradation products of high impact polystyrene / decabromodiphenylether / antimony oxide (HIPS FR) have been studied in situ with derivative thermogravimetry (DTG), temperature resolved pyrolysis-mass spectrometry (Py-MS).
65 citations
TL;DR: In workers exposed to pentavalent Sb, the urinary Sb excretion is related to the intensity of exposure, and it has been estimated that after eight hours exposure to 500 micrograms Sb/m3, the increase of urinary SB concentration at the end of the shift amounts on average to 35micrograms/g creatinine.
Abstract: Unlike inorganic arsenic, inorganic trivalent antimony (Sb) is not methylated in vivo. It is excreted in the bile after conjugation with glutathione and also in urine. A significant proportion of that excreted in bile undergoes an enterohepatic circulation. In workers exposed to pentavalent Sb, the urinary Sb excretion is related to the intensity of exposure. It has been estimated that after eight hours exposure to 500 micrograms Sb/m3, the increase of urinary Sb concentration at the end of the shift amounts on average to 35 micrograms/g creatinine.
47 citations
TL;DR: In this paper, the corrosion processes at open circuit conditions and in the active dissolution region of antimony, at low anodic overpotentials, have been studied in sulphuric acid solutions.
45 citations
44 citations
TL;DR: The behavior of a Pb+12% Sb electrode (eutectic composition) in the lead oxide and the lead dioxide potential regions has been investigated in this paper, where the electrode was first oxidized at a constant potential for 0.5 h and then subjected to negative potential sweeps at a scan rate of 10 mV/s.
40 citations
TL;DR: The formation of an anodic layer during the oxidation of antimony in sulphuric acid solutions as well as the structure and properties of the layer have been studied using linear sweep voltammetry, potentiostatic oxidation, ac impedance measurements, X-ray diffraction analysis and scanning electron microscopy as discussed by the authors.
TL;DR: A tubular electrode is devised and filled with PbO2 powder produced by grinding the active material obtained on a lead-grip plate as mentioned in this paper, which is isolated in such a way that its contact with the H2SO4 solution is realized only through the pores of the active materials.
TL;DR: In this article, the influence of Sb on the formation of the corrosion layer on Pb has been studied with a Pb-12%Sb alloy electrode in sulphuric acid solution using the ring-disk technique decay measurement and galvanostatic oxidation.
TL;DR: In this paper, the solvent extraction of antimony (in), bismuth (111), lead (II), and tin (IV) from aqueous hydrochloric acid solutions by bis(2,4,4-trimethylpentyl) phosphinodithioic acid (Cyanex 301® denoted HL) in kerosene + 10 % v/v n-decanol was investigated.
Abstract: The solvent extraction of antimony (in), bismuth (111), lead (II) and tin (IV) from aqueous hydrochloric acid solutions by bis(2,4,4-trimethylpentyl) phosphinodithioic acid (Cyanex 301® denoted HL) in kerosene + 10 % v/v n-decanol was investigated. Lead (II), tin (IV), bismuth (III) and antimony (III) are efficiently extracted by Cyanex 301® up to about 5, 6, 9 and 11 mol.L1− HCl, respectively. The corresponding extracted species were identified as PbL2, SnCl2L2, BiL3 and SMvj. However, it was observed that Sn (IV) can be moderately extracted from the aqueous phase by the mere mixture of kerosene and n-decanol above 9 mol.L1−HCl. In all cases, extraction equilibrium was reached within a few minutes. Finally, a thermodynamic modelling of the extraction system was developed in the particular case of lead (II).
TL;DR: In this paper, a number of transition metal clusters which incorporate bismuth and antimony have been reported, and the structures and reaction chemistry of these complexes are compared, as well as their properties.
Abstract: In recent years a number of transition metal clusters which incorporate bismuth and antimony have been reported. The structures and reaction chemistry of these complexes are compared.
TL;DR: In this study, data recorded with glass microelectrodes or antimony electrodes, both with external cutaneous Ag/AgCl reference electrodes, connected to two different recording devices are compared.
Abstract: Oesophageal pH monitoring data are influenced by numerous patient or technique related factors, or both. In this study, data recorded with glass microelectrodes or antimony electrodes, both with external cutaneous Ag/AgCl reference electrodes, connected to two different recording devices are compared. Pearson correlation coefficients regarding the reflux index (% of the investigation time with a pH less than 4) ranged from poor to excellent (0.55 to 1.00). Differences in data recorded with glass electrodes are not significantly dependent on the recording device (r:0.93 to 1.00 for the reflux index). The correlation between data simultaneously recorded with antimony electrodes is lower, although not significantly different for the reflux index (0.90). Correlation between data recorded with glass and antimony probes is rather poor (0.55 to 0.70). Therefore data recorded with antimony electrodes cannot be compared with those recorded with glass electrodes. The mean pH recorded with glass electrodes is lower than that with antimony probes.
TL;DR: In this article, the analytical performance of flow-injection and continuous-flow-hydride generation AAS was compared and the optimum physical and chemical conditions for hydride generation and transport were given for the two methods.
TL;DR: In this paper, the authors performed simultaneous determination of antimony and bismuth from 0.5 M HCl solution that contained 0.1 M hydrazine, using the hanging mercury electrode by differential pulse anodic stripping voltammetry with very slow potential scan rate and small pulse amplitude.
Abstract: Simultaneous determination of antimony and bismuth was performed from 0.5 M HCl solution that contained 0.1 M hydrazine, using the hanging mercury electrode by differential pulse anodic stripping voltammetry with very slow potential scan rate and small pulse amplitude. The influence of HCl and chloride concentrations on the peak shape of Bi and Sb and the influence of other ions and organic substances were investigated. For the determination of antimony and bismuth in water and snow samples, the UV irradiation and the reduction of Sb(V) to SE(III) by hydrazine in boiling solution were applied. The detection limit for Bi and Sb is 20 ng L−1.
Patent•
13 Aug 1991TL;DR: Corrosion inhibitor additives are added directly to an aqueous acid solution used in acidizing underground formations as discussed by the authors, consisting of a metal selected from antimony and antimony mixtures, a quaternary compound, and a surfactant.
Abstract: Corrosion inhibitor additives are added directly to an aqueous acid solution used in acidizing subterranean formations. The additives consist essentially of a metal selected from antimony and antimony mixtures, a quaternary compound, and a surfactant. The corrosion inhibitor is free of toxic acetylenic compounds.
TL;DR: In this article, a method for the determination of total antimony, extractable into 4 mol dm −3 HCl, and SbIII, which combines a slurry procedure with hydride generation atomic absorption spectrometry, is described.
Abstract: A method is described for the determination of total antimony, extractable into 4 mol dm–3 HCl, and SbIII, which combines a slurry procedure with hydride generation atomic absorption spectrometry. The lack of a matrix effect allows the analytical results to be obtained with a simple aqueous working curve. The detection limit in solid samples is 13.3 and 8.35 ng g–1 for SbIII and total antimony, respectively. The proposed method for the determination of total antimony provides a better recovery than that obtained by digestion with a mixture of HNO3–H2SO4–HClO4 but worse than that obtained by digestion with HF.
Patent•
15 Mar 1991
TL;DR: In this paper, the authors present catalysts for producing phthalic anhydride by vapor phase catalytic oxidation of orthoxylene and/or naphthalene with molecular oxygen or gas containing molecular oxygen.
Abstract: The invention presents catalysts for producing phthalic anhydride by vapor phase catalytic oxidation of orthoxylene and/or naphthalene with molecular oxygen or gas containing molecular oxygen. The catalyst is prepared by supporting a catalytic active substance comprising 1 to 20 parts by weight (hereinafter abbreviated "parts") of vanadium oxide as V₂O₃, 99 to 80 parts of anatase type titanium dioxide with specific surface area of 10 to 60 m²/g as TiO₂ and per 100 parts of the sum of these two ingredients, 0.05 to 1.2 parts of at least one element selected from potassium, cesium, rubidium and thallium as oxide, and 0.05 to 2 parts of silver as Ag₂O on a heat resistant inorganic carrier. The catalyst may also contain, per 100 parts in total of vanadium oxide and titanium dioxide, 0 to 1 part of niobium as Nb₂O₅, 0 to 1.2 parts of phosphorus as P₂O₃, and 0 to 5 parts of antimony as Sb₂O₃ (however, contents of niobium, phosphorus and antimony will not be zero at the same time).
TL;DR: In this article, electron density changes corresponding to antimony substitution at the Wyckoff 2(c) and 2(d) sites of P63/m, between Ca(l) (threefold) positions were used to reach these conclusions.
Abstract: Comparison of powder X-ray diffraction data from a 2-2 wt% antimony-substituted calcium fluorapatite [0.185 Sb atoms per unit cell containing CaloF2(PO4)6] with data from an undoped sample shows electron density changes corresponding to antimony substitution at the Ca(2) (mirror) site. Many properties of this 2.2 wt% Sb sample indicate that it corresponds to commercial halophosphate phosphors of lower Sb concentration. Differing properties are shown by a 3.1 wt% Sb sample for which no diffraction evidence is found for substitution at the Ca(2) site, but for which electron density difference maps do suggest substitution at the Wyckoff 2(c) and 2(d) sites of P63/m, between Ca(l) (threefold) positions. Both Rietveld refinements and Fourier inversion of the differences between observed intensities were used to reach these conclusions.
Patent•
17 Sep 1991
TL;DR: In this article, a process for producing a crystalline iron antimonate and at least one element selected from the group consisting of vanadium, molybdenum, and tungsten is described.
Abstract: A composition which contains as essential components: crystalline iron antimonate and at least one element selected from the group consisting of vanadium, molybdenum, and tungsten; is useful as a catalyst in the oxidation reaction of organic compounds. Also, a process for producing the composition is disclosed.
TL;DR: In this paper, a systematic investigation of the formation of MO − x ions (x = 1, 2 or 3) for the elements P, As, and Sb using negative thermal ionization mass spectrometry is presented.
TL;DR: In this article, the flame-retarding mechanism of polypropylene containing a chlorine system has been explored by XPS(ESCA), and a wealth of information such as chemical states of chlorine and antimony in the surface as a function of temperature were obtained, some of which was obtained previously by techniques associated with the bulk properties.
TL;DR: In this paper, a low-energy cluster beam deposition technique was used to obtain continuous amorphous antimony thin films, which are stable at room temperature, by combining electrical measurements and transmission electron microscopy observations.
Abstract: We have prepared continuous amorphous antimony thin films by low‐energy cluster beam deposition. Contrary to the antimony films prepared by molecular beam deposition, this new technique allows preparation of continuous amorphous films which are stable at room temperature. This study has been carried out by combining electrical measurements and transmission electron microscopy observations.
TL;DR: The antimony-III-silver-I and salt-sodium-I complexes with citric acid have been prepared and their crystal structures determined by X-ray diffraction and refined to residuals of R= 0.023 and 0.017 for 2403 and 2969 observed reflections respectively as discussed by the authors.
Abstract: The antimony(III)–silver(I) and –sodium(I) complexes with citric acid (C6H8O7), [Sb2Ag2(C6H6O7)4]1 and [SbNa(C6H6O7)2(H2O)2]·H2O 2, have been prepared and their crystal structures determined by X-ray diffraction and refined to residuals of R= 0.023 and 0.017 for 2403 and 2969 observed reflections respectively. Crystals are monoclinic, space group P21/n, and P21/a Complex 1 has two dimers in a cell of dimensions a= 6.557(4), b= 12.149(2), c= 20.50(1)A and β= 98.12(3)°, while there are four monomers of 2 in a cell with a= 14.470(5), b= 7.193(3), c= 18.747(6)A and β= 92.22(2)°. In each structure antimony is bonded to two oxygens of two crystallographically independent citrate(2–) residues in classic pseudo-trigonal-bipyramidal antimony(III) four-co-ordination [Sb–O 2.007(2)–2.218(2), 1; 1.988(1)–2.164(1)A, 2]. These oxygens are from the α-hydroxycarboxylate groups giving five-membered chelate rings. In 1 each antimony centre is in turn linked through one of these carboxylate groups to two silver(I) ions in an asymmetric bis(carboxylato-O,O′) bridge [Ag–O 2.314(2) and 2.661(2)A]. Hydroxyl groups complete the angular three-co-ordination about each silver [Ag–O 2.323(2)A], giving a centrosymmetric cyclic dimer structure. In contrast, complex 2 is monomeric with the sodium and two co-ordinated waters [Na–Ow 2.404(2) and 2.512(2)A] forming a tris(oxo)-bridged complex unit (two oxygens from the α-hydroxycarboxy groups), with a Na–O range of 2.413(2)–2.562(2)A[Na ⋯ Sb 3.665(1)A].
TL;DR: In this paper, it was shown that Sb ions dissolved during the oxidation exist in H2SO4 in the trivalent state even at potentials well above the equilibrium potential of the Sb(V)/Sb(III) couple.