Showing papers on "Antimony published in 1977"

A Raman and far-infrared investigation of phonons in the rhombohedral V2–VI3 compounds Bi2Te3, Bi2Se3, Sb2Te3 and Bi2(Te1−xSex)3 (0 < x < 1), (Bi1−ySby)2Te3 (0 < y < 1)

Abstract: The Raman-active lattice vibrations of Bi2Se3, Bi2Te3, Sb2Te3, and their solid slutions, whose symmetries correspond to the R3m space group, are investigated by Raman scattering. Three of the four expected Raman modes, Eg and A1g, could be determined. The FIR optical properties of Bi2Te3 crystal surfaces of improved quality (E ∥ c and E ⟂ c) and Bi2Se3 (E ⟂ c) are re-examined near helium and room temperature with a Fourier spectrometer, allowing a determination of the infrared-active mode frequencies with higher accuracy. The results for Bi2Te3 are compared to the predicted frequencies from the lattice dynamical model, given by Jenkins et al. The frequncy shifts of the Raman-active modes in the mixed crystals show single-mode and two-mode behaviour, which is in agreement with simple models for the substitution of antimony and selenium atoms for bismuth and tellurium, respectively, in Bi2Te3.

Zinc deposit structures obtained from high purity synthetic and industrial acid sulphate electrolytes with and without antimony and glue additions

Abstract: A characteristic morphology and crystal orientation; namely (112) (114) (102), has been obtained for zinc deposits electrowon from high purity synthetic and industrial acid sulphate electrolytes. These deposit characteristics persisted over a wide range of experimental conditions which included variations in the applied current density and changes in the anode materials and cathode pretreatments. The addition of either antimony or glue to the electrolyte produced deposit morphologies and orientations which were distinctly different from those obtained for addition-free electrolytes. When both antimony and glue additions were made to the electrolyte, however, the deposit morphologies and crystal orientations were similar to those obtained from addition-free solutions. The various deposit morphologies and orientations obtained were shown to correlate with changes occurring in the zinc deposition overvoltage.

Polymeric article coated with a thermochromic paint

Abstract: An article comprising a polymeric material and coated with a thermochromic paint. 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 phoshorus; the oxides and the 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.

Cracking with catalyst modified by antimony thiophosphate

Abstract: Prevention of detrimental effect of metals such as nickel, vanadium and iron on the activity of a cracking catalyst when used in a cracking process having essentially no hydrogen added thereto is achieved by using in the cracking process novel cracking catalyst having less than 40 weight percent zeolite content and including antimony metal or a compound of antimony prior to subjecting the cracking catalyst to hydrocarbon cracking conditions.

Antimony oxide–PVC synergism: Laser pyrolysis studies of the interaction mechanism

Abstract: Laser-probe pyrolysis is used to investigate the synergistic flame-retardancy effect observed for antimony oxide (Sb2O3)–PVC combinations. Molecular beam-mass analysis detection techniques permit direct sampling of the laser-vaporized species without the need for intermediate product collection stages. Laser pyrolysis of a PVC formulation containing 3 phr Sb2O3 provides the first direct evidence for the production of volatile SbCl3 during thermal decomposition. Selective laser irradiation of PVC in the presence of unheated Sb2O3 in the sample cell reveals that HCl evolved from the polymer substrate rapidly reacts with Sb2O3(s) to form the volatile flame-retardant species SbCl3. Similar results are observed for SbOCl(s). These reactions are distinct from those previously proposed, which involve the formation and subsequent thermal decomposition of intermediate solid-phase antimony oxychlorides, and demonstrate that the antimony compounds, rather than serving only as inert sources for SbCl3, readily participate in direct chemical reactions with HCl. In addition to the composition of the reaction products, information is also obtained on their evolution characteristics from the sample cell.

Normalkonformationen achtgliedriger Heterocyclen mit transannular gebundenem Germanium, Zinn, Arsen und Antimon

Abstract: Fur am Element Ge, Sn, As und Sb Chlor-substituierte 1,3,6-Trichalkogena-2-elementocane werden Normalkonformationen, Normalbindungslangen, Normalkoordinationen des Elements und Normalbindungswinkel angegeben und diskutiert. Standard Conformations of 8-Membered Heterocycles with Transannular Bonded Germanium, Tin, Arsenic, and Antimony Standard values of conformations, bond lengths, coordinations of the element, and bond angles are given and discussed for 1,3,6-trichalcogena-2-elementocanes with chlorine substituted element Ge, Sn, As, and Sb, respectively.

Temperature dependence study of the quadrupole interaction of 111 Cd in antimony

Abstract: A power law dependence has been observed for the temperature dependence of the quadrupole interaction of the 247 keV state of111Cd in antimony, which is similar to that observed for121Sb and123Sb in antimony.

Functional alloy for use in automated soldering processes

Abstract: .[.A solder alloy for use in automated soldering of workpieces by application thereto of liquid solder from a molten reservoir. The alloy consists essentially of from about 50 to 57.5% by weight tin, from about 1.5 to 4% by weight antimony, with the balance being substantially lead. The alloy is preferably further characterized in displaying a solidus-to-liquidus temperature range no greater than that of a 60/40 weight ratio tin/lead solder..]..Iadd. An improved process for machine soldering a workpiece by application thereto of a liquid solder from a molten reservoir is disclosed. The improvement resides in the use of solder alloys having a composition of approximately 55% tin, 2.77% antimony, the remainder being substantially lead or approximately 52% tin, 3% antimony, the remainder being substantially lead..Iaddend.

Determination of arsenic, antimony, and selenium in coal by atomic absorption spectrometry with a graphite tube atomizea

Abstract: Submicrogram quantities of antimony, arsenic, and selenium in coal samples are determined by an atomic absorption procedure using an electrically heated graphite atomizer. The samples are decomposed in a mixture of nitric, sulfuric, and perchloric acids and are separated and concentrated by extraction from sulfuric acid-iodide solution into toluene. The results obtained on several intralaboratory reference samples and the National Bureau of Standards coal 1632 are compared with results from other methods. The determination can be made routinely for concentrations as small as 0.1 parts per million for arsenic, antimony, and selenium in the coal.

Preparation, structure and properties of complexes with the bis(di‐n‐butyldithiocarbamato)arsenic(III) or antimony(III) cation

Abstract: The preparation, structure and some physical properties of cationic dithiocarbamatoarsenic(III) and -antimony(III) compounds [M(Bu2dtc)2] + X− [X = I−3 for M = As and Sb; X = Cd2I2−6 for M - Sb and Bu2dtc− = Bu2NC(S)S−] are reported. [Sb(Bu2dtc)2]2Cd2I6, crystallizing in the monoclinic space group P21/n with a = 16.236(6), b = 12.573(5), c = 16.126(5) A, β = 94.13(2)°, V = 3283 A3 and Z = 2, contains Sb in pseudo-trigonal-bipyramidal coordination, with a stereoactive lone pair in an equatorial position. The Bu2dtc groups are asymmetrically bonded, with their largest Sb-S bonds in equatorial direction.

Extraction of antimony from antimony sulfides bearing solids

Abstract: A method for extracting antimony from solids containing antimony sulfides is described. An improvement in the method of extracting antimony by oxidation of an aqueous mixture of the solids in an acid or by oxidation of a leaching liquor obtained by leaching the antimony from the solids with an aqueous basic solution comprises conducting the oxidation in the presence of a catalyst comprising a water-soluble copper salt, a quinone, a hydroquinone or mixtures of one or more of these. The catalyst significantly increases the rate of oxidation and the rate of the recovery of the antimony from antimony sulfide bearing solids, particularly natural ores. Where the oxidation is conducted in a basic solution, the antimony is recovered as pentavalent antimony in the form of metal antimonates. Facile reduction of the metal antimonate to antimony trioxide also is described.

Non-empirical valence-electron molecular orbital calculations: spin-orbit splitting in the ion states of the tin and antimony halides

Abstract: The non-empirical valence-electron (NEVE) molecular orbital method can accommodate molecules containing p-block atoms up to the fourth row in a minimum STO basis calculation. Unlike many MO methods in current use, the NEVE method allows comparisons down the Periodic Table. The present study illustrates this for the tin tetrahalides and antimony trihalides. The calculated orbital eigenvalues correlate well with the photoelectron spectra of these compounds, and by using a semi-empirical spin-orbit hamiltonian theoretical spin-orbit splitting patterns are obtained. The calculated splittings are generally smaller for the antimony trihalides, and a revised assignment of the photoelectron spectrum of antimony tri iodide is suggested.

Red sensitive photocathode having an aluminum oxide barrier layer

Abstract: In a photomultiplier tube, antimony layers of a photocathode are prepared on a nickel substrate by providing a barrier layer of aluminum oxide between the substrate and antimony layers. The photocathode is subsequently exposed to the vapors of at least one alkali metal to sensitize the antimony layers. The aluminum oxide layer prevents alloying of the nickel with the antimony at processing temperatures in the range from 260° C. to 285° C. and provides a source of oxygen to oxidize the photocathode for increased photosensitivity, the oxidation time being a function of the thickness of the aluminum oxide layer. The photocathode is then exposed to cesium and may be superficially oxidized until substantially maximum photosensitivity is achieved.

The121Sb Mössbauer spectra of antimony-containing glasses

Abstract: The121Sb Mossbauer spectra of a series of Na2O-B2O3-Sb2O3, (Na2O, 2P2O5) + Sb2O3, and (Na2O, 2SiO2) + Sb2O3 glasses have been measured. The chemical isomer shifts,δ, and the quadrupole couplings,eQVzz, for antimony (III) in different glasses have been estimated. From the changes of isomer shift is has been deduced that the ionicity of the Sb-O bond increases with decreasing Na2O content in Na2O-B2O3-Sb2O3 glasses; and when the network former is changed, with equivalent molar composition, the ionicity of the Sb-O bond increased in the order borate ⩽ silicate < phosphate.

Method for the separation of antimony(III) from antimony(V) using polyurethane foam

Abstract: Antimony(III) and antimony(V) in solution can be separated by adjusting the pH to 9.5 and shaking with sodium diethyldithiocarbamate (NaDDC) and polyurethane foam. Alternatively, the solution can be passed through a column of foam that has previously been treated with 5%m/V of NaDDC in carbon tetrachloride. The Sb(DDC)3 complex retained by the foam can be eluted with acetone. DDC complexes of iron(III), mercury and silver are also absorbed, but are unlikely to interfere in the subsequent determination of antimony by either atomic-absorption spectrophotometry or neutronactivation analysis.

Electrode grids for lead accumulators

Abstract: An electrode grid for lead accumulators, said grid being formed from a lead alloy free from antimony and consisting of tellurium, arsenic and silver in a total concentration of at most 0.1% by weight, at least 0.1% tin by weight of the alloy, and the balance pure lead.

The complex antimony-lead/zinc deposit at Rujevac/Yugoslavia; its specific geochemical and mineralogical features

Abstract: During the last years, several large complex antimony deposits (Sb-Pb/Zn-As association) have been discovered in Yugoslavia. One of these deposits is Rujevac in western Serbia. Genetically related to the Tertiary granodioritic magma, the mineral parageneses are characterized by some specific features. So, pyrite displays occasionally a zonal pattern of arsenic distribution: the marginal zones contain up to 6 wt% of As. Besides common galena, antimoniferous galena containing up to 10. 5% of Sb is known. Among lead sulphantimonides, some new species are indicated. The paragenetic sequence of the Pb-Sb-S minerals indicates that the fluctuations in the chemical potential of Sb2S3, influenced by the presence of lead and antimony in the ore-bearing hydrothermal solutions, and geochemistry of the deposit, were such that they resulted in formation of an order of deposition like stibnite → lead sulphantimonides → galena. This order of crystallization seems to be characteristic of some complex Sb-Pb-S ores.

Valency states of radioactive antimony in hydrochloric acid solutions. Preparation and stability of antimony tracer for radioanalytical use

Abstract: Variations of125Sb valency states in HCl solutions were investigated by the use of the N-benzoyl-N-phenyl-hydroxylamine (BPHA) extraction method.125Sb(V) is completely reduced to Sb(III) by one hour refluxing in conc. HCl.125Sb(III) is gradually oxidized to Sb(V) in solutions of low HCl concentrations by the effects of their own radiations. Natural light promotes such oxidation reactions. By utilizing such oxidation-reduction effects125Sb(V) can be easily prepared from125Sb(III) and also125Sb(III) can be prepared by the reduction of Cl aq − . Their valency states were stable on keeping them in brown-colored bottles at 6M HCl concentrations.