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Barium Ferrite
Barium ferrite, abbreviated BaFe, BaM, is the chemical compound with the formula BaFe12O19. This and related ferrite materials are components in magnetic stripe cards and loudspeaker magnets. BaFe is described as Ba2+(Fe3+)12(O2−)19. The Fe3+ centers are ferrimagnetically coupled, and one unit cell of BaM has a net magnetic moment of 40''μ''B. This area of technology is usually considered to be an application of the related fields of materials science and solid state chemistry. Barium ferrite is a highly magnetic material, has a high packing density, and is a metal oxide. Studies of this material date at least as far back as 1931, and it has found applications in magnetic card strips, speakers, and magnetic tapes. One area in particular it has found success in is long-term data storage; the material is magnetic, resistant to temperature change, corrosion and oxidization. Chemical structure The Fe3+ centers, with a high-spin d5 configuration, are ferrimagnetically cou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrite (magnet)
A ferrite is a ceramic material made by mixing and firing large proportions of iron(III) oxide (Fe2O3, rust) blended with small proportions of one or more additional metallic elements, such as strontium, barium, manganese, nickel, and zinc. They are ferrimagnetic, meaning they can be magnetized or attracted to a magnet. Unlike other ferromagnetic materials, most ferrites are not electrically conductive, making them useful in applications like magnetic cores for transformers to suppress eddy currents. Ferrites can be divided into two families based on their resistance to being demagnetized (magnetic coercivity). Hard ferrites have high coercivity, so are difficult to demagnetize. They are used to make permanent magnets for applications such as refrigerator magnets, loudspeakers, and small electric motors. Soft ferrites have low coercivity, so they easily change their magnetization and act as conductors of magnetic fields. They are used in the electronics industry to make efficien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexagonal Close-packed
In geometry, close-packing of equal spheres is a dense arrangement of congruent spheres in an infinite, regular arrangement (or lattice). Carl Friedrich Gauss proved that the highest average density – that is, the greatest fraction of space occupied by spheres – that can be achieved by a lattice packing is :\frac \approx 0.74048. The same packing density can also be achieved by alternate stackings of the same close-packed planes of spheres, including structures that are aperiodic in the stacking direction. The Kepler conjecture states that this is the highest density that can be achieved by any arrangement of spheres, either regular or irregular. This conjecture was proven by T. C. Hales. Highest density is known only for 1, 2, 3, 8, and 24 dimensions. Many crystal structures are based on a close-packing of a single kind of atom, or a close-packing of large ions with smaller ions filling the spaces between them. The cubic and hexagonal arrangements are very close to one anoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. It is a trace gas in Earth's atmosphere at 421 parts per million (ppm), or about 0.04% by volume (as of May 2022), having risen from pre-industrial levels of 280 ppm. Burning fossil fuels is the primary cause of these increased CO2 concentrations and also the primary cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA Carbon dioxide is soluble in water and is found in groundwater, lakes, ice ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barium Carbonate
Barium carbonate is the inorganic compound with the formula BaCO3. Like most alkaline earth metal carbonates, it is a white salt that is poorly soluble in water. It occurs as the mineral known as witherite. In a commercial sense, it is one of the most important barium compounds. Preparation Barium carbonate is made commercially from barium sulfide by treatment with sodium carbonate at 60 to 70 °C (soda ash method) or, more commonly carbon dioxide at 40 to 90 °C: In the soda ash process, an aqueous solution of barium sulfide is treated with sodium carbonate: :BaS + H2O + CO2 → BaCO3 + H2S Reactions Barium carbonate reacts with acids such as hydrochloric acid to form soluble barium salts, such as barium chloride: : + 2 HCl → + + Pyrolysis of barium carbonate gives barium oxide. Uses It is mainly used to remove sulfate impurities from feedstock of the chlor-alkali process. Otherwise it is a common precursor to barium-containing compounds such as ferrite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butterworths
LexisNexis is a part of the RELX corporation that sells data analytics products and various databases that are accessed through online portals, including portals for computer-assisted legal research (CALR), newspaper search, and consumer information. During the 1970s, LexisNexis began to make legal and journalistic documents more accessible electronically. , the company had the world's largest electronic database for legal and public-records–related information. History LexisNexis is owned by RELX (formerly known as Reed Elsevier). According to Trudi Bellardo Hahn and Charles P. Bourne, LexisNexis (originally founded as LEXIS) is historically significant because it was the first of the early information services to envision a future in which large populations of end users would directly interact with computer databases, rather than going through professional intermediaries like librarians. Available through IEEE Xplore. Other early information services in the 1970s met with f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron(III) Oxide
Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturally as the mineral magnetite. As the mineral known as hematite, Fe2O3 is the main source of iron for the steel industry. Fe2O3 is readily attacked by acids. Iron(III) oxide is often called rust, and to some extent this label is useful, because rust shares several properties and has a similar composition; however, in chemistry, rust is considered an ill-defined material, described as Hydrous ferric oxide. Structure Fe2O3 can be obtained in various polymorphs. In the main one, α, iron adopts octahedral coordination geometry. That is, each Fe center is bound to six oxygen ligands. In the γ polymorph, some of the Fe sit on tetrahedral sites, with four oxygen ligands. Alpha phase α-Fe2O3 has the rhombohedral, corundum (α-Al2O3) structure and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barium Carbonate
Barium carbonate is the inorganic compound with the formula BaCO3. Like most alkaline earth metal carbonates, it is a white salt that is poorly soluble in water. It occurs as the mineral known as witherite. In a commercial sense, it is one of the most important barium compounds. Preparation Barium carbonate is made commercially from barium sulfide by treatment with sodium carbonate at 60 to 70 °C (soda ash method) or, more commonly carbon dioxide at 40 to 90 °C: In the soda ash process, an aqueous solution of barium sulfide is treated with sodium carbonate: :BaS + H2O + CO2 → BaCO3 + H2S Reactions Barium carbonate reacts with acids such as hydrochloric acid to form soluble barium salts, such as barium chloride: : + 2 HCl → + + Pyrolysis of barium carbonate gives barium oxide. Uses It is mainly used to remove sulfate impurities from feedstock of the chlor-alkali process. Otherwise it is a common precursor to barium-containing compounds such as ferrite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcination
Calcination refers to thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), generally for the purpose of removing impurities or volatile substances and/or to incur thermal decomposition. The root of the word calcination refers to its most prominent use, which is to remove carbon from limestone (calcium carbonate) through combustion to yield calcium oxide (quicklime). This calcination reaction is CaCO3(s) → CaO(s) + CO2(g). Calcium oxide is a crucial ingredient in modern cement, and is also used as a chemical flux in smelting. Industrial calcination generally emits carbon dioxide (), making it a major contributor to climate change. A calciner is a steel cylinder that rotates inside a heated furnace and performs indirect high-temperature processing (550–1150 °C, or 1000–2100 °F) within a controlled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bentham Science Publishers
Bentham Science Publishers is a company that publishes scientific, technical, and medical journals and e-books. It publishes over 100 subscription-based academic journals and almost 40 open access journals. As of 2021, 40 Bentham Science journals have received JCR impact factors, and they are a member of the Committee on Publication Ethics. ''Bentham Open'', its open access division, has received criticism for questionable peer-review practices as well as invitation spam; it was listed as a "potential, possible, or probable predatory scholarly open access publisher" in Jeffrey Beall's list of predatory publishers, before the list went defunct. History Bentham was incorporated in 1994 by Atta-ur-Rahman and his friend Matthew Honan as a private business entity at the Sharjah Airport International Free Trade Zone in the United Arab Emirates. An investigative profile from ''Sujag'' notes the publisher to have operated out of Pakistan — for the first six years, from the premis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Citrate
Sodium citrate may refer to any of the sodium salts of citric acid (though most commonly the third): * Monosodium citrate * Disodium citrate * Trisodium citrate The three forms of salt are collectively known by the E number E331. Applications Food Sodium citrates are used as acidity regulators in food and drinks, and also as emulsifiers for oils. They enable cheeses to melt without becoming greasy. It reduces the acidity of food as well. Blood clotting inhibitor Sodium citrate is used to prevent donated blood from clotting in storage. It is also used in a laboratory, before an operation, to determine whether a person's blood is too thick and might cause a blood clot, or if the blood is too thin to safely operate. Sodium citrate is used in medical contexts as an alkalinizing agent in place of sodium bicarbonate, to neutralize excess acid in the blood and urine. Metabolic acidosis It has applications for the treatment of metabolic acidosis and chronic kidney disease. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferric Nitrate
Iron(III) nitrate, or ferric nitrate, is the name used for a series of inorganic compounds with the formula Fe(NO3)3.(H2O)n. Most common is the nonahydrate Fe(NO3)3.(H2O)9. The hydrates are all pale colored, water-soluble paramagnetic salts. Hydrates Iron(III) nitrate is deliquescent, and it is commonly found as the nonahydrate Fe(NO3)3· 9H2O, which forms colourless to pale violet crystals. This compound is the trinitrate salt of the aquo complex e(H2O)6sup>3+. Other hydrates ·''x'', include: * tetrahydrate (''x''=4), more precisely triaqua dinitratoiron(III) nitrate monohydrate, ·, has complex cations where atom is coordinated with two nitrate anions as bidentate ligands and three of the four water molecules, in a pentagonal bipyramid configuration with two water molecules at the poles.H. Schmidt, A. Asztalos, F. Bok and W. Voigt (2012): "New iron(III) nitrate hydrates: ·''x'' with ''x'' = 4, 5 and 6". ''Acta Crystallographica Section C - Inorganic Compounds'', volume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali that decomposes proteins at ordinary ambient temperatures and may cause severe chemical burns. It is highly soluble in water, and readily absorbs moisture and carbon dioxide from the air. It forms a series of hydrates . The monohydrate crystallizes from water solutions between 12.3 and 61.8 °C. The commercially available "sodium hydroxide" is often this monohydrate, and published data may refer to it instead of the anhydrous compound. As one of the simplest hydroxides, sodium hydroxide is frequently used alongside neutral water and acidic hydrochloric acid to demonstrate the pH scale to chemistry students. Sodium hydroxide is used in many industries: in the manufacture of pulp and paper, textiles, drinking water, soap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
