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Bromide Ion
A bromide ion is the negatively charged form (Br−) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colorless. Bromides have many practical roles, being found in anticonvulsants, flame-retardant materials, and cell stains. Although uncommon, chronic toxicity from bromide can result in bromism, a syndrome with multiple neurological symptoms. Bromide toxicity can also cause a type of skin eruption, see potassium bromide. The bromide ion has an ionic radius of 196 pm. Natural occurrence Bromide is present in typical seawater (35 PSU) with a concentration of around 65 mg/L, which is about 0.2% of all dissolved salts. Seafood and deep sea plants generally have higher levels than land-derived foods. Bromargyrite—natural, crystalline silver bromide—is the most common bromide mineral known but is still very rare. In addition to silver, bromine is also in minerals combined with mercury and copper. Formation and reacti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Bromide
Hydrogen bromide is the inorganic compound with the formula . It is a hydrogen halide consisting of hydrogen and bromine. A colorless gas, it dissolves in water, forming hydrobromic acid, which is saturated at 68.85% HBr by weight at room temperature. Aqueous solutions that are 47.6% HBr by mass form a constant-boiling azeotrope mixture that boils at 124.3 °C. Boiling less concentrated solutions releases H2O until the constant-boiling mixture composition is reached. Hydrogen bromide, and its aqueous solution, are commonly used reagents in the preparation of bromide compounds. Reactions Organic chemistry Hydrogen bromide and hydrobromic acid are important reagents in the production of organobromine compounds.Greenwood, N. N.; Earnshaw, A. Chemistry of the Elements; Butterworth-Heineman: Oxford, Great Britain; 1997; pp. 809–812.Vollhardt, K. P. C.; Schore, N. E. Organic Chemistry: Structure and Function; 4th Ed.; W. H. Freeman and Company: New York, NY; 2003. In a free-r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrobromic Acid
Hydrobromic acid is a strong acid formed by dissolving the diatomic molecule hydrogen bromide (HBr) in water. "Constant boiling" hydrobromic acid is an aqueous solution that distills at and contains 47.6% HBr by mass, which is 8.77 mol/L. Hydrobromic acid has a p''K''a of −9, making it a stronger acid than hydrochloric acid, but not as strong as hydroiodic acid. Hydrobromic acid is one of the strongest mineral acids known. Uses Hydrobromic acid is mainly used for the production of inorganic bromides, especially the bromides of zinc, calcium, and sodium. It is a useful reagent for generating organobromine compounds. Certain ethers are cleaved with HBr. It also catalyzes alkylation reactions and the extraction of certain ores. Industrially significant organic compounds prepared from hydrobromic acid include allyl bromide, tetrabromobis(phenol), and bromoacetic acid. HBr almost uniquely participates in anti-Markovnikov hydrohalogenation of alkenes. The resulting 1-bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gelatin Silver Process
The gelatin silver process is the most commonly used chemical process in black-and-white photography, and is the fundamental chemical process for modern analog color photography. As such, films and printing papers available for analog photography rarely rely on any other chemical process to record an image. A suspension of silver salts in gelatin is coated onto a support such as glass, flexible plastic or film, baryta paper, or resin-coated paper. These light-sensitive materials are stable under normal keeping conditions and are able to be exposed and processed even many years after their manufacture. This was an improvement on the collodion wet-plate process dominant from the 1850s–1880s, which had to be exposed and developed immediately after coating. History The gelatin silver process was introduced by Richard Leach Maddox in 1871 with subsequent considerable improvements in sensitivity obtained by Charles Harper Bennett in 1878. Gelatin silver print paper was made as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Tribromide
Aluminium bromide is any chemical compound with the empirical formula AlBrx. Aluminium tribromide is the most common form of aluminium bromide. It is a colorless, sublimable hygroscopic solid; hence old samples tend to be hydrated, mostly as aluminium tribromide hexahydrate (AlBr3·6H2O). Structure The dimeric form of aluminium tribromide (Al2Br6) predominates in the solid state, in solutions in noncoordinating solvents (e.g. CS2), in the melt, and in the gas phase. Only at high temperatures do these dimers break up into monomers: : Al2Br6 → 2 AlBr3 ΔH°diss = 59 kJ/mol The species aluminium monobromide forms from the reaction of HBr with Al metal at high temperature. It disproportionates near room temperature: :6/n " lBrsub>n" → Al2Br6 + 4 Al This reaction is reversed at temperatures higher than 1000 °C. Aluminium monobromide has been crystallographically characterized in the form the tetrameric adduct Al4Br4(NEt3)4 (Et = C2H5). This species is electronical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc(II) Bromide
Zinc bromide ( Zn Br2) is an inorganic compound with the chemical formula Zn Br2. It is a colourless salt that shares many properties with zinc chloride (ZnCl2), namely a high solubility in water forming acidic solutions, and good solubility in organic solvents. It is hygroscopic and forms a dihydrate ZnBr2·2H2O. Production ZnBr2 · 2H2O is prepared by treating zinc oxide or zinc metal with hydrobromic acid. : ZnO + 2HBr + H2O → ZnBr2·2H2O : Zn + 2HBr → ZnBr2 + H2 The anhydrous material can be produced by dehydration of the dihydrate with hot CO2 or by reaction of zinc metal and bromine. Sublimation in a stream of hydrogen bromide also gives the anhydrous derivative. Structure ZnBr2 crystallizes in the same structure as ZnI2: four tetrahedral Zn centers share three vertices to form “super-tetrahedra” of nominal composition 2−, which are linked by their vertices to form a three-dimensional structure. The dihydrate ZnBr2 · 2H2O can be described as ( n(H2O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper(I) Bromide
Copper(I) bromide is the chemical compound with the formula CuBr. This diamagnetic solid adopts a polymeric structure akin to that for zinc sulfide. The compound is widely used in the synthesis of organic compounds and as a lasing medium in copper bromide lasers. Preparation, basic properties, structure The compound is white, although samples are often colored due to the presence of copper(II) impurities. The copper(I) ion also oxidizes easily in air. It is commonly prepared by the reduction of cupric salts with sulfite in the presence of bromide.This report gives a procedure for generating CuBr: For example, the reduction of copper(II) bromide with sulfite yields copper(I) bromide and hydrogen bromide: :2 CuBr2 + H2O + → 2 CuBr + + 2 HBr CuBr is insoluble in most solvents due to its polymeric structure, which features four-coordinated, tetrahedral Cu centers interconnected by bromide ligands (ZnS structure). Upon treatment with Lewis bases, CuBr converts t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Bromide
Ammonium bromide, NH4Br, is the ammonium salt of hydrobromic acid. The chemical crystallizes in colorless prisms, possessing a saline taste; it sublimes on heating and is easily soluble in water. On exposure to air it gradually assumes a yellow color because of the oxidation of traces of bromide (Br−) to bromine (Br2). Preparation Ammonium bromide can be prepared by the direct action of hydrogen bromide on ammonia. : NH3 + HBr → NH4Br It can also be prepared by the reaction of ammonia with iron(II) bromide or iron(III) bromide, which may be obtained by passing aqueous bromine solution over iron filings. : 2 NH3 + FeBr2 + 2 H2O → 2 NH4Br + Fe(OH)2 Reactions Ammonium bromide is a weak acid with a pKa of ~5 in water. It is an acid salt because the ammonium ion hydrolyzes slightly in water. Ammonium Bromide is strong electrolyte when put in water: :NH4Br(s) → NH4+(aq) + Br−(aq) Ammonium bromide decomposes to ammonia and hydrogen bromide when heated at elevated tempe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Bromide
Sodium bromide is an inorganic compound with the formula Na Br. It is a high-melting white, crystalline solid that resembles sodium chloride. It is a widely used source of the bromide ion and has many applications.Michael J. Dagani, Henry J. Barda, Theodore J. Benya, David C. Sanders "Bromine Compounds" in ''Ullmann's Encyclopedia of Industrial Chemistry'' Wiley-VCH, Weinheim, 2000. Synthesis, structure, reactions NaBr crystallizes in the same cubic motif as NaCl, NaF and NaI. The anhydrous salt crystallizes above 50.7 °C. Dihydrate salts (NaBr·2H2O) crystallize out of water solution below 50.7 °C. NaBr is produced by treating sodium hydroxide with hydrogen bromide. Sodium bromide can be used as a source of the chemical element bromine. This can be accomplished by treating an aqueous solution of NaBr with chlorine gas: :2 NaBr + Cl2 → Br2 + 2 NaCl Applications Sodium bromide is the most useful inorganic bromide in industry. It is also used as a catalyst in T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Bromide
Lithium bromide (LiBr) is a chemical compound of lithium and bromine. Its extreme hygroscopic character makes LiBr useful as a desiccant in certain air conditioning systems.Wietelmann, Ulrich and Bauer, Richard J. (2005) "Lithium and Lithium Compounds" in ''Ullmann's Encyclopedia of Industrial Chemistry'' Wiley-VCH: Weinheim. Production and properties LiBr is prepared by treating an aqueous suspension of lithium carbonate with hydrobromic acid or by reacting lithium hydroxide with bromine. It forms several crystalline hydrates, unlike the other alkali metal bromides. Lithium hydroxide and hydrobromic acid (aqueous solution of hydrogen bromide) will precipitate lithium bromide in the presence of water. :LiOH + HBr → LiBr + H2O Uses A 50–60% aqueous solution of lithium bromide is used in air-conditioning systems as desiccant. It is also used in absorption chilling along with water (see absorption refrigerator). Solid LiBr is a useful reagent in organic synthesis. It is inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organobromine Compound
Organobromine compounds, also called organobromides, are organic compounds that contain carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon ma ... Chemical bond, bonded to bromine. The most pervasive is the naturally produced bromomethane. One prominent application of synthetic organobromine compounds is the use of polybrominated diphenyl ethers as fire-retardants, and in fact fire-retardant manufacture is currently the major industrial use of the element bromine. A variety of minor organobromine compounds are found in nature, but none are biosynthesized or required by mammals. Organobromine compounds have fallen under increased scrutiny for their environmental impact. General properties Most organobromine compounds, like most organohalogens, organohalide compounds, are relative ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitric Acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitric acid has a concentration of 68% in water. When the solution contains more than 86% , it is referred to as ''fuming nitric acid''. Depending on the amount of nitrogen dioxide present, fuming nitric acid is further characterized as red fuming nitric acid at concentrations above 86%, or white fuming nitric acid at concentrations above 95%. Nitric acid is the primary reagent used for nitration – the addition of a nitro group, typically to an organic molecule. While some resulting nitro compounds are shock- and thermally-sensitive explosives, a few are stable enough to be used in munitions and demolition, while others are still more stable and used as pigments in inks and dyes. Nitric acid is also commonly used as a strong oxidizing agen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bleach
Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to a dilute solution of sodium hypochlorite, also called "liquid bleach". Many bleaches have broad spectrum bactericidal properties, making them useful for disinfecting and sterilizing. They are used in swimming pool sanitation to control bacteria, viruses, and algae, and in many places where sterile conditions are required. They are also used in many industrial processes, notably in the bleaching of wood pulp. Bleaches also have other minor uses like removing mildew, killing weeds, and increasing the longevity of cut flowers. Bleaches work by reacting with many colored organic compounds, such as natural pigments, and turning them into colorless ones. While most bleaches are oxidizing agents (chemicals that can remove electrons from other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
