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Silver(I) Oxide
Silver oxide is the chemical compound with the formula Ag2 O. It is a fine black or dark brown powder that is used to prepare other silver compounds. Preparation Silver oxide can be prepared by combining aqueous solutions of silver nitrate and an alkali hydroxide. This reaction does not afford appreciable amounts of silver hydroxide due to the favorable energetics for the following reaction: :( p''K'' = 2.875) With suitably controlled conditions, this reaction can be used to prepare Ag2O powder with properties suitable for several uses including as a fine grained conductive paste filler. Structure and properties Ag2O features linear, two-coordinate Ag centers linked by tetrahedral oxides. It is isostructural with Cu2O. It "dissolves" in solvents that degrade it. It is slightly soluble in water due to the formation of the ion and possibly related hydrolysis products. It is soluble in ammonia solution, producing active compound of Tollens' reagent. A slurry of Ag2O is readil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixed-valence Complex
Mixed valence complexes contain an element which is present in more than one oxidation state. Well-known mixed valence compounds include the Creutz–Taube complex, Prussian blue, and molybdenum blue. Many solids are mixed-valency including indium chalcogenides. Robin–Day classification Mixed-valence compounds are subdivided into three groups, according to the Robin–Day classification: *Class I, where the valences are trapped—localized on a single site—such as Pb3O4 and antimony tetroxide. There are distinct sites with different specific valences in the complex that cannot easily interconvert. *Class II, which are intermediate in character. There is some localization of distinct valences, but there is a low activation energy for their interconversion. Some thermal activation is required to induce electron transfer from one site to another via the bridge. These species exhibit an intense Intervalence charge transfer (IT or IVCT) band, a broad intense absorption i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkali Hydroxide
The alkali hydroxides are a class of chemical compounds which are composed of an alkali metal cation and the hydroxide anion (). The alkali hydroxides are: *Lithium hydroxide (LiOH) *Sodium hydroxide (NaOH) *Potassium hydroxide (KOH) * Rubidium hydroxide (RbOH) * Caesium hydroxide (CsOH) * Francium hydroxide (FrOH) Production Alkali hydroxides are formed in the reaction between alkali metals and water. A typical school demonstration demonstrates what happens when a piece of an alkali metal is introduced to a bowl of water. A vigorous reaction occurs, producing hydrogen gas and the specific alkali hydroxide. For example, if sodium is the alkali metal: : Sodium hydroxide is an important industrial chemical, where it is produced by the chloralkali process. Properties and uses The alkali metal hydroxides form white crystals that are hygroscopic and readily soluble in water, generating large amounts of heat upon dissolution. The solubility increases down the column as the alkali m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linus Pauling
Linus Carl Pauling ( ; February 28, 1901August 19, 1994) was an American chemist and peace activist. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. ''New Scientist'' called him one of the 20 greatest scientists of all time. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. For his peace activism, he was awarded the Nobel Peace Prize in 1962. He is one of five people to have Nobel Prize#Multiple laureates, won more than one Nobel Prize. Of these, he is the only person to have been awarded two unshared Nobel Prizes, and one of two people to be awarded Nobel Prizes in different fields, the other being Marie Curie. Pauling was one of the founders of the fields of quantum chemistry and molecular biology. His contributions to the theory of the chemical bond include the concept of orbital hybridisation and the first accurate scale of electronegativity, electronegativities of the elements. Pauling also wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver Chloride
Silver chloride is an inorganic chemical compound with the chemical formula Ag Cl. This white crystalline solid is well known for its low solubility in water and its sensitivity to light. Upon illumination or heating, silver chloride converts to silver (and chlorine), which is signaled by grey to black or purplish coloration in some samples. AgCl occurs naturally as the mineral chlorargyrite. It is produced by a metathesis reaction for use in photography and in pH meters as electrodes. Preparation Silver chloride is unusual in that, unlike most chloride salts, it has very low solubility. It is easily synthesized by metathesis: combining an aqueous solution of silver nitrate (which is soluble) with a soluble chloride salt, such as sodium chloride (which is used industrially as a method of producing AgCl), or cobalt(II) chloride. The silver chloride that forms will precipitate immediately. : : It can also be produced by the reaction of silver metal and aqua regia; howev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trifluoroacetic Acid
Trifluoroacetic acid (TFA) is a synthetic organofluorine compound with the chemical formula CF3CO2H. It belongs to the subclass of per- and polyfluoroalkyl substances (PFASs) known as ultrashort-chain perfluoroalkyl acids (PFAAs). TFA is not produced biologically or abiotically and is commonly used in organic chemistry for various purposes. It is the most abundant PFAS found in the environment. It is a haloacetic acid, with all three of the acetyl group's hydrogen atoms replaced by fluorine atoms. It is a colorless liquid with a vinegar-like odor. TFA is a stronger acid than acetic acid, having an acid ionisation constant, ''K''a, that is approximately 34,000 times higher, as the highly electronegative fluorine atoms and consequent electron-withdrawing nature of the trifluoromethyl group weakens the oxygen-hydrogen bond (allowing for greater acidity) and stabilises the anionic conjugate base. Synthesis TFA is prepared industrially by the electrofluorination of ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroiodic Acid
Hydroiodic acid (or hydriodic acid) is a colorless liquid. It is an aqueous solution of hydrogen iodide with the chemical formula . It is a strong acid, in which hydrogen iodide is ionized completely in an aqueous solution. Concentrated aqueous solutions of hydrogen iodide are usually 48% to 57% HI by mass. Preparation Reactions Hydroiodic acid reacts with oxygen in air to give iodine: : Like hydrogen halides, hydroiodic acid adds to alkenes to give alkyl iodides. It can also be used as a reducing agent, for example in the reduction of aromatic nitro compounds to anilines. Cativa process The Cativa process is a major end use of hydroiodic acid, which serves as a co-catalyst for the production of acetic acid by the carbonylation of methanol. Illicit uses Hydroiodic acid is listed as a U.S. Federal DEA List I Chemical, owing to its use as a reducing agent related to the production of methamphetamine from ephedrine or pseudoephedrine Pseudoephedrine, sold under the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrobromic Acid
Hydrobromic acid is an aqueous solution of hydrogen bromide. It 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 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 participates in anti-Markovnikov hydrohalogenation of alkenes in the presence of peroxides. The resulting 1-bromoalkanes are versatile alkylating agents, giving rise to fatty amines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrochloric Acid
Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is a component of the gastric acid in the digestive systems of most animal species, including humans. Hydrochloric acid is an important laboratory reagent and industrial chemical. Etymology Because it was produced from halite, rock salt according to the methods of Johann Rudolph Glauber, hydrochloric acid was historically called by European alchemists ''spirits of salt'' or ''acidum salis'' (salt acid). Both names are still used, especially in other languages, such as , , , , , , , , , , (''ensan''), zh, 盐酸 (''yánsuān''), and (''yeomsan''). Gaseous HCl was called ''marine acid air''. The name ''muriatic acid'' has the same origin (''muriatic'' means "pertaining to brine or salt", hence ''muriate'' means hydrochloride), and this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrofluoric Acid
Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colorless, acidic and highly corrosive. A common concentration is 49% (48–52%) but there are also stronger solutions (e.g. 70%) and pure HF has a boiling point near room temperature. It is used to make most organofluorine compounds; examples include the commonly used pharmaceutical antidepressant medication fluoxetine (Prozac) and the material PTFE (Teflon). Elemental fluorine is produced from it. It is commonly used to etch glass and silicon wafers. Uses Production of organofluorine compounds The principal use of hydrofluoric acid is in organofluorine chemistry. Many organofluorine compounds are prepared using HF as the fluorine source, including Teflon, fluoropolymers, fluorocarbons, and refrigerants such as freon. Many pharmaceuticals contain fluorine. Production of inorganic fluorides Most high-volume inorganic fluoride compounds are prepared from hydrofluoric acid. Foremost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slurry
A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a centrifugal pump. The size of solid particles may vary from 1 micrometre up to hundreds of millimetres. The particles may settle below a certain transport velocity and the mixture can behave like a Newtonian or non-Newtonian fluid. Depending on the mixture, the slurry may be abrasive and/or corrosive. Examples Examples of slurries include: *Cement slurry, a mixture of cement, water, and assorted dry and liquid additives used in the petroleum and other industries *Soil/cement slurry, also called Controlled Low-Strength Material (CLSM), flowable fill, controlled density fill, flowable mortar, plastic soil-cement, K-Krete, and other names *A mixture of thickening agent, oxidizers, and water used to form a gel explosive *A mixture of pyroclastic materi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tollens' Reagent
Tollens' reagent (chemical formula Ag(NH3)2OH) is a chemical reagent used to distinguish between aldehydes and ketones along with some alpha-hydroxy ketones which can tautomerize into aldehydes. The reagent consists of a solution of silver nitrate, ammonium hydroxide and some sodium hydroxide (to maintain a basic pH of the reagent solution). It was named after its discoverer, the German chemist Bernhard Tollens. A positive test with Tollens' reagent is indicated by the precipitation of elemental silver, often producing a characteristic " silver mirror" on the inner surface of the reaction vessel. Laboratory preparation This reagent is not commercially available due to its short shelf life, so it must be freshly prepared in the laboratory. One common preparation involves two steps. First a few drops of dilute sodium hydroxide are added to some aqueous 0.1 M silver nitrate. The OH- ions convert the silver aquo complex form into silver(I) oxide, Ag2O, which precipitat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pungent smell. It is widely used in fertilizers, refrigerants, explosives, cleaning agents, and is a precursor for numeous chemicals. Biologically, it is a common nitrogenous waste, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to fertilisers. Around 70% of ammonia produced industrially is used to make fertilisers in various forms and composition, such as urea and diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many chemicals. In many countries, it is classified as an List of extremely hazardous substances, extremely hazardous substance. Ammonia is toxic, cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
