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Sound Production
Published in John A. Conkling, Christopher J. Mocella, Chemistry of Pyrotechnics, 2019
John A. Conkling, Christopher J. Mocella
A relatively new effect in the field of entertainment pyrotechnics is a crackling effect (numerous snapping or popping sounds) produced by a “thermite”-type reaction between a metal oxide and a metal.2 The original “crackle” compositions that were introduced into the fireworks market by China contained lead tetroxide—also known as “red lead” oxide—with formula Pb3O4 and magnalium as the fuel. Replacement formulations were later developed to remove the toxic lead, again based on thermite-type metal oxide–metal reactions, have been developed using bismuth(III) oxide and copper(II) oxide in place of lead tetroxide, again with magnalium as the fuel (Jennings-White 1992). The addition of coarse (>100 mesh) titanium metal particles with these compositions produce a spectacular white spark effect in addition to the crackling effect (T. Shimizu, Studies on mixtures of lead oxides with metals [magnalium, aluminum, or magnesium] 1990).
Carbon Nanotube-Metal Oxide Hybrid Nanocomposites Synthesis and Applications
Published in Zainovia Lockman, 1-Dimensional Metal Oxide Nanostructures, 2018
Zaid Aws Ali Ghaleb, Mariatti Jaafar
Semiconductor metal oxide has been a prominent example of a sensing material used in gas sensors since 1962. It has been widely used for detection of different gases due to their electrical properties that are highly affected by the surrounding gas environment. Gas sensors were made from metal oxides such as bismuth (III) oxide (Bi2O3), SnO2, ZnO, TiO2, indium (III) oxide In2O3, gallium (III) oxide Ga2O3, WO3, and Fe2O (Aroutiounian, 2007). For example, WO3 shows sensitivity to pollutants such as sulfur dioxide (SO2), hydrogen sulfide (H2S), nitric oxide (NO), and NH3, while SnO2 is sensitive to NOx, carbon monoxide (CO), ethanol, and acetylene (C2H4). The advantages of semiconductor metal oxide gas sensors are their rather high sensitivity, simple design, and low cost. However, these sensors continue to suffer from high temperatures from the pre-heating of the sensor body; further degradation is due to growth and aggregation, as well as lack of selectivity, which limits their applications. For example, conventional SnO2 sensors do not perform well when operated at room temperature. SnO2 sensor operates at temperatures between 200°C and 500°C (Berry and Brunet, 2008). Many commercial SnO2-based sensor devices have been realized to detect organic compounds and hazardous gases such as CO and NO. These gas sensors often operate at high temperatures up to 400°C in order to realize high gas sensitivity (Aroutiounian, 2015).
Minerals of radioactive metals
Published in Francis P. Gudyanga, Minerals in Africa, 2020
Although bismuth is normally stable at room temperatures, when exposed to both dry and moist air, it forms bismuth(III) oxide; when reacted with water at a time it is red hot 2Bi+3H2O→Bi2O3+3H2 and dissolves in concentrated sulphuric acid, nitric acid, hydrochloric acid to form its sulphate, nitrate and chloride, respectively: 6H2SO4+2Bi→6H2O+Bi2SO43+3SO2Bi+6HNO3→3H2O+3NO2+BiNO334Bi+3O2+12HCl→4BiCl3+6H2O When reacted with fluorine, bismuth forms bismuth(V) fluoride at 500° C or bismuth(III) at lower temperatures. With the other halides it forms only trihalides: 2Bi+3X2→2BiX3(X=F,Cl,Br,I) These trihalides easily react with moisture to form oxyhalides BiOX.
Synthesis of acicular α-Bi2O3 microcrystals by microwave-assisted hydrothermal method
Published in Particulate Science and Technology, 2019
Samara Schmidt, Evaldo T. Kubaski, Diogo P. Volanti, Thiago Sequinel, Vinicius D. N. Bezzon, Sergio M. Tebcherani
Materials based on bismuth(III) oxide (Bi2O3) are candidate to be used in optical and electronic devices because of their properties such as a variable band gap (from 2.00 to 3.96 eV), photoconductivity, photoluminescence, high refractive index, and dielectric permittivity (Kim et al. 2013; Vila, Diaz-Guerra, and Piqueras 2013). These properties are dependent of several factors, e.g., present phases and crystal morphology. In Bi2O3 the band bap varies depending on the phases present in the material and, in the case of nanoparticles, the band gap can also vary according to changes in particle size (Xinglong et al. 2009; Vila, Diaz-Guerra, and Piqueras 2012; Ho et al. 2013). Among the Bi2O3 polymorphic phases, the monoclinic bismuth oxide (α-Bi2O3) is stable at room temperature and its structure was reported by Malmros (1970) (space group P21/c, a = 5.8486 Å, b = 8.1661 Å, α = γ = 90° and β = 113.00°, and cell volume = 330.15 Å3).
Multivariate comparison of photocatalytic properties of thirteen nanostructured metal oxides for water purification
Published in Journal of Environmental Science and Health, Part A, 2019
Jakub Trawiński, Robert Skibiński
Water with 0.1% acetic acid for LC-MS, methanol for LC-MS, titanium(IV) oxide, nanopowder 21 nm particle size, ≥99.5% trace metals basis (Aeroxide® 25), zinc oxide, nanopowder, <100 nm particle size, ∼80% Zn basis, and tungsten(VI) oxide, nanopowder, <100 nm particle size, were purchased from Sigma Aldrich Co. (St. Louis, USA). Acetonitrile gradient grade for liquid chromatography, and water gradient grade for liquid chromatography were purchased from Merck (Darmstadt, Germany). Strontium titanate, nanopowder, 100 nm particle size (cubic phase), 99.9%, nickel(II) oxide, nanopowder 10–20 nm particle size, 99%, bismuth(III) oxide, nanopowder 80 nm particle size, 99.9%, zirconium(IV) oxide, nanopowder 40 nm particle size, ≥ 99%, cobalt(II, III) oxide, nanopowder 10–30 nm particle size, 99%, tin(IV) oxide, nanopowder 35–55 nm particle size, 99.7%, zinc iron oxide, nanopowder 10–30 nm particle size, 98.5%, cerium(IV) oxide, nanopowder 10–30 nm particle size, 99.97%, iron(III) oxide alpha, nanopowder 20–40 nm particle size, ≥ 98%, and praseodymium(III, IV) oxide, nanopowder 15–55 nm particle size, 99.9%, were purchased from US Research Nanomaterials, Inc. (Houston, USA). The TEM images of those oxides (provided by the manufacturer) were provided in the Supplementary material (Supplementary Materials Figs. 1S–10S).
Recent advantages in the metal (bulk and nano)-catalyzed S-arylation reactions of thiols with aryl halides in water: a perfect synergy for eco-compatible preparation of aromatic thioethers
Published in Journal of Sulfur Chemistry, 2018
Esmail Vessally, Khadijeh Didehban, Robab Mohammadi, Akram Hosseinian, Mirzaagha Babazadeh
Recently, by utilizing commercially available bismuth(III)oxide catalyst, Malik and Chakraborty demonstrated highly efficient C–S cross-coupling reactions of thiols 30 with aryl halides 31 in water. Various ligands and bases were tested in order to optimize the reaction conditions and the combination of N,N-dimethylethane-1,2-diamine and KOH proved most effective. The optimized protocol resulted in functionalized diaryl thioether frameworks 32 in high yields and tolerated a variety of sensitive functional groups, including chloro, bromo, methoxy, nitro, and amino functionalities that would allow further elaboration of the products (Scheme 13). It is noted that the catalyst was recycled over five runs without significant loss of activity and selectivity (89–90% yield over all runs). The mechanism shown in Scheme 14 was proposed for this process. It consists of the following key steps: (i) coordination of the ligand to Bi2O3 forms bismuth complex A; (ii) coordination of the aryl halide 31 to complex A affords intermediate B; (iii) nucleophilic attack of thiol 30 to the active aryl halide B furnishes the intermediate C; and (iv) reductive elimination of intermediate C gives the final products 32 [42].