Showing papers on "Antimony published in 1975"

Interferences in the determination of elements that form volatile hydrides with sodium borohydride using atomic-absorption spectrophotometry and the argon-hydrogen flame

Abstract: A study has been made of the determination of arsenic, bismuth, germanium, antimony, selenium, tin and tellurium by conversion into the hydrides by reaction with sodium borohydride in dilute hydrochloric acid followed by measurement with atomic-absorption spectrophotometry in an argon-hydrogen flame. A general study, involving 48 elements, of interferences has been carried out and it has been shown that significant interference occurs in many instances but that the procedure is simple to carry out and gives a considerable increases in sensitivity and detection limits for the elements listed, with the exception of tin, for which high blank values were obtained owing to the presence of tin in the sodium borohydride reagent.

Photopolymerization co-initiator systems

Abstract: A photopolymerization co-initiator system comprises (a) about 1-30 parts of at least one carbonyl-containing compound, (b) about 1-30 parts of an organic compound containing nitrogen, phoshorus, arsenic, bismuth, or antimony, and (c) about 1-30 parts of at least one halogenated hydrocarbon.

The atomic-fluorescence determination of antimony, arsenic, selenium and tellurium by using the hydride generation technique

Abstract: The method of determination of antimony, arsenic, selenium and tellurium, by using a sodium borohydride reduction with subsequent atomic fluorescence, was found to be very sensitive.The calibration graphs were linear over a wide range of concentrations and the method was 5–30 times more sensitive than the corresponding atomic-absorption technique.

Five-coordinate Bromobis(dialkyldithiocarbamate) Complexes of Arsenic, Antimony, and Bismuth

Abstract: Fifteen bromobis(dialkyldithiocarbamate) complexes of arsenic, antimony, and bismuth have been prepared by reacting the corresponding tris(dialkyldithiocarbamates) with bromine. The structure of these compounds is studied by i.r., n.m.r., and electronic spectra. From the interpretation of the spectroscopic data it is deduced that each dithiocarbamate group acts as a bidentate ligand. The spectral data are discussed and compared to those of the corresponding tris(dialkyldithiocarbamate) complexes.

Nature of an intergranular thin−film phase in a highly non−Ohmic metal oxide varistor

Abstract: A detailed examination by transmission electron microscopy and selected−area diffraction revealed that the thin−film intergranular phase in a highly non−Ohmic multicomponent metal oxide varistor system based on ZnO with small additions of antimony, bismuth, cobalt, manganese, and tin oxides is amorphous and is chemically related to a Bi2O3−rich pyrochlore coexisting in the ceramic.

High-energy photoelectron spectroscopy of some antimony compounds

Abstract: High-energy photoelectron (p.e.) spectra have been obtained for a number of compounds of antimony. The antimony 3d(,5//2) binding energies range from 542.9, 533.3 eV for [Et4N][SbF6] to 538.6, 529.0 eV for Bun3Sb, but there is little correlation with the formal oxidation state. Assignment of the oxidation state of antimony on the basis of X-ray p.e. data alone is not possible with certainty and even gross structural differences may remain undetected by this method.

Valence States of Arsenic and Antimony in Sea Water

Abstract: A simple and convenient chemical procedure for the determination of As(III), As(V), Sb(III) and Sb(V) by thermal neutron activation analysis is proposed and applied to the study of the valence state of As and Sb in sea water. Immediately after sampling, As(III) and Sb(III) were separated from As(V) and Sb(V) by extracting their diethyldithiocarbamates with chloroform, and then back-extracted into diluted nitric acid. As(V) and Sb(V) in the aqueous phase were collected by thionalide cocrystallization. They were then irradiated for 30 min at a neutron flux of 2×1013 n/(cm2·s), and treated in the same manner as described in the previous report. The As and Sb were determined by gamma-ray spectrometry. Sea water has been found to contain 1.56–2.45 μg As/l and 0.37–0.60 μg Sb/l. 80–97% of arsenic and 70–94% of antimony existed as the pentavelent species, only 5–20% as the trivalent species, and the remainder was probably included in suspended matter.

Thermochromic paint for use on plastic substrates

Abstract: A thermochromic paint, which changes color when heated to a certain temperature, and which is particularly suited for use on plastic substrates which are subject to oxidative degradation is disclosed. The improvement comprises the addition to the thermochromic paint of a non-thermochromic compound selected from the group consisting of the sulfates, hydrated sulfates and nitrides of boron, aluminum, tin, lead, arsenic, antimony, bismuth, zinc and phosphorus; the sulfides and hydrated sulfides of boron, aluminum, bismuth and phosphorus; the oxides and hydrated oxides of boron, arsenic, antimony and phosphorus and the salts, organic compounds and free acids of the oxyanions of boron, arsenic, antimony and phosphorus.

The Determination of Barium and Antimony in Gunshot Residue by Flameless Atomic Absorption Spectroscopy Using a Tantalum Strip Atomizer

Abstract: A flameless atomic absorption technique, employing a tantalum strip atomizer, has been developed to determine barium and antimony in gunshot residue. Cotton swabs, wetted with 5% HNO3, are used to collect residue. Barium and antimony are released from the swabs by acid leaching or plasma ashing. Both techniques give good recoveries; the ashing technique is preferred for blood-stained swabs. The sensitivity for barium is 0.1 ng/10 μl and antimony 0.2 ng/10 μl. At nanogram levels the standard relative deviation for barium is 8.3% and for antimony 8.5%.

The diffusion of antimony in alpha iron

Abstract: Diffusion coefficients of antimony in α-iron were determined in the temperature range 700 to 900°C using the residual activity method. Specimens were large-grained polycrystals for the higher temperature measurements and single crystals for the low temperature measurements. Above 800°C the data may be represented by the equationD sb(cm2/s) = (440 ± 200) exp [- (270,000 ± 7000)/RT]. The activation energy (reported in J/mole) is approximately equal to that measured for iron self-diffusion in this same temperature range, although the antimony diffusion coefficients are a factor of ten larger than the iron self diffusion coefficients. The potential for strongly coupled vacancy-antimony motions is demonstrated, based on the observed enhancement of iron self diffusion in dilute iron-antimony alloys. Finally molybdenum is shown to have a negligible effect on the diffusion of antimony in α-iron. These results are discussed in relation to the phenomenon of temper brittleness in steels. Embrittlement kinetics in iron-antimony alloys are shown to be consistent with an antimony diffusion controlled segregation mechanism.

Effects of the presence of valence-shell non-bonding electron pairs on the properties and structures of caesium tin(II) bromides and of related antimony and tellurium compounds

Abstract: The ideal perovskite structure of CsSnIIBr3 at room temperature has been confirmed by a single-crystal X-ray diffraction study. It is proposed that the high-symmetry environment for the SnII in this compound arises because the distorting effect of the non-bonding electrons is reduced by their populating an empty low-energy band in the solid, thus giving rise to the black colour and metallic-conducting properties. The high-temperature phases of CsSn2IIBr5, Cs4SnIIBr6, and of compositions from the CsSnII2Br5–CsSnII2Cl5 system show similar properties. Colour can be introduced into the Cs2SnIVBr6 system by formation of mixed phases with CsSnIIBr3 which has a closely related structure. The colour and electrical properties of the mixed SnII–SnIV material can be explained by population of the low-energy delocalised solid-state bands by the SnII non-bonding electrons without recourse to intervalence-transfer-absorption ideas. Comparison of the complex bromides and chlorides of SnII and TeIV with the mixed-valence SbIII–SbV compounds suggests that direct population of bands rather than intervalence charge transfer may also be the dominant process in determining the properties of the antimony derivatives, l.r. data for the mixed-valence antimony compounds are consistent with the direct-population explanation.

Vinyl halide stabilizer compositions of antimony organic sulfur-containing compounds and ortho-dihydric phenols

Abstract: A vinyl halide resin stabilizer composition which essentially contains: A. an antimony organic sulfur-containing compound, for example, antimony alkyl mercaptides, antimony mercaptoacid esters and the like, and B. an ortho-dihydric phenol, such as catechol, t-butyl catechol and 2,3-dihydroxy naphthalene. These compositions synergistically contribute to the heat stability of vinyl halide resin compositions and offer significant heat stabilization economies. Early color as well as long term heat stability performances of antimony organic compounds are improved in the compositions disclosed thereby permitting the reduction in amounts of such compounds needed for stabilization. Stabilizer compositions which are liquids and shelf-stable at ambient temperatures are also disclosed.

Automated Determination of Arsenic, Selenium, Antimony, Bismuth and Tin by Atomic Absorption Utilizing Sodium Borohydride Reduction

Abstract: An automated system for the determination of arsenic, selenium, antimony, bismuth and tin is described. These elements and their compounds are reduced with sodium borohydride to the corresponding hydride. Sensitivity of the automated system is comparable and in most cases better than the manual technique. The automated method was found superior to the manual with respect to reproducibility and ease of operation.

Determination of uranium, antimony, indium, bromine and cobalt in atmospheric aerosols using epithermal neutron activation and a low-energy photon detector

Abstract: Owing to the high ratio of resonance integral to thermal neutron activation cross-section of238U, a 5 min epithermal neutron irradiation under cadmium shielding, followed by measurement of the 74 keV photopeak of239U with a high resolution low-energy photon Ge(Li) detector, allows the fast determination of uranium in aerosols collected on a Whatman 41 cellulose filter. Uranium blanks of the cellulose filter paper require correction and limit the sensitivity. Simultaneously the concentrations of the elements cobalt, bromine, antimony and indium can be determined. In Belgium, the uranium concentrations of the aerosols were found to be constant and comparable to the uranium contents of rocks.

Studies on antimony oxides: Part I

Abstract: Thermogravimetry (TG), differential thermal analysis (DTA) and X-ray diffraction studies of antimony(III) oxide, (Sb2O3), in air, nitrogen and argon atmospheres have been made.

Aromatic Thiocyanation by a Mixture of Antimony(V) Chloride and Lead(II) Thiocyanate

Abstract: Alkyl- and halobenzenes give thiocyano-derivatives when treated with a mixture of SbCl5 and Pb(SCN)2 in CCl4. The reaction proceeds via in situ formation of ClSCN from SbCl5 and Pb(SCN)2 followed by its attack on aromatic compounds catalyzed by SbCl5, the reaction species being SCN+SbCl6−.

Determination of diffusion, partition and sticking coefficients for boron, phosphorus and antimony in silicon

Abstract: Our model (1) for impurity transfer into epitaxial films grown by sublimation at U.H.V. is improved by the use of a more complete set of boundary conditions to be met by the solution of the diffusion equation. Detailed measurements are given of impurity profiles for layers grown from boron, phosphorus or antimony doped sources. These are used to obtain their diffusion and partition coefficients in the source as well as their sticking coefficient on the substrate. The dependence of these parameters on temperature is also reported, giving a basis for prediction of profiles under various experimental conditions.