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IUPAC name Cobalt boride | |
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Properties | |
CoB | |
Molar mass | 69.744 |
Appearance | Refractory Solid |
Density | 7.25 g/cm3 |
Melting point | 1,460 °C (2,660 °F; 1,730 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Cobalt borides are inorganic compounds with the general formula CoxBy. [1] The two main cobalt borides are CoB and Co2B. These are refractory materials.
Cobalt borides are known to be exceptionally resistant to oxidation, a chemical property which makes them useful in the field of materials science. For instance, studies suggest cobalt boride can increase the lifespan of metal parts when used as a coating, imparting surfaces with higher corrosion and wear resistance. These properties have been exploited in the field of biomedical sciences for the design of specialized drug delivery systems. [2]
Cobalt boride has also been studied as a catalyst for hydrogen storage and fuel cell technologies. [3]
Cobalt boride is also an effective hydrogenation catalyst used in organic synthesis. [4] In one study, cobalt boride was found to be the most selective transition metal based catalyst available for the production of primary amines via nitrile reduction, even exceeding other cobalt containing catalysts such as Raney cobalt. [5]
Cobalt boride is produced under high temperature such as 1500 °C. Coatings of cobalt boride on iron are produced by boriding, which involves first introducing a coating of FeB, Fe2B. On to this iron boride coating is deposited cobalt using a pack cementation process. [2] Cobalt boride nanoparticles in the size range of 18 to 22 nm have also been produced. [6]
When used as a catalyst, cobalt boride is prepared by reducing a cobalt salt, such as cobalt(II) nitrate, with sodium borohydride. [4] [7] Prior to reduction, the surface area of the catalyst is maximized by supporting the salt on another material; often this material is activated carbon.
In chemistry, a hydride is formally the anion of hydrogen (H−), a hydrogen atom with two electrons. In modern usage, this is typically only used for ionic bonds, but it is sometimes (and more frequently in the past) been applied to all compounds containing covalently bound H atoms. In this broad and potentially archaic sense, water (H2O) is a hydride of oxygen, ammonia is a hydride of nitrogen, etc. In covalent compounds, it implies hydrogen is attached to a less electronegative element. In such cases, the H centre has nucleophilic character, which contrasts with the protic character of acids. The hydride anion is very rarely observed.
Diborane(6), commonly known as diborane, is the chemical compound with the formula B2H6. It is a highly toxic, colorless, and pyrophoric gas with a repulsively sweet odor. Given its simple formula, borane is a fundamental boron compound. It has attracted wide attention for its electronic structure. Several of its derivatives are useful reagents.
Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula Li[AlH4] or LiAlH4. It is a white solid, discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters, carboxylic acids, and amides. The solid is dangerously reactive toward water, releasing gaseous hydrogen (H2). Some related derivatives have been discussed for hydrogen storage.
Tungsten carbide is a chemical compound containing equal parts of tungsten and carbon atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes through sintering for use in industrial machinery,engineering facility,mold industry ,cutting tools, chisels, abrasives, armor-piercing bullets and jewelry.
Titanium diboride (TiB2) is an extremely hard ceramic which has excellent heat conductivity, oxidation stability and wear resistance. TiB2 is also a reasonable electrical conductor, so it can be used as a cathode material in aluminium smelting and can be shaped by electrical discharge machining.
Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula NaBH4. It is a white crystalline solid, usually encountered as an aqueous basic solution. Sodium borohydride is a reducing agent that finds application in papermaking and dye industries. It is also used as a reagent in organic synthesis.
Raney nickel, also known as the primary catalyst for the Cormas-Grisius Electrophilic Benzene Addition, is a fine-grained solid composed mostly of nickel derived from a nickel–aluminium alloy. Several grades are known, of which most are gray solids. Some are pyrophoric, but most are used as air-stable slurries. Raney nickel is used as a reagent and as a catalyst in organic chemistry. It was developed in 1926 by American engineer Murray Raney for the hydrogenation of vegetable oils. Raney Nickel is a registered trademark of W. R. Grace and Company. Other major producers are Evonik and Johnson Matthey.
Nanomaterial-based catalysts are usually heterogeneous catalysts broken up into metal nanoparticles in order to enhance the catalytic process. Metal nanoparticles have high surface area, which can increase catalytic activity. Nanoparticle catalysts can be easily separated and recycled. They are typically used under mild conditions to prevent decomposition of the nanoparticles.
Borohydride refers to the anion [BH4]−, which is also called tetrahydridoborate, and its salts. Borohydride or hydroborate is also the term used for compounds containing [BH4−nXn]−, where n is an integer from 0 to 3, for example cyanoborohydride or cyanotrihydroborate [BH3(CN)]− and triethylborohydride or triethylhydroborate [BH(CH2CH3)3]−. Borohydrides find wide use as reducing agents in organic synthesis. The most important borohydrides are lithium borohydride and sodium borohydride, but other salts are well known. Tetrahydroborates are also of academic and industrial interest in inorganic chemistry.
Lithium borohydride (LiBH4) is a borohydride and known in organic synthesis as a reducing agent for esters. Although less common than the related sodium borohydride, the lithium salt offers some advantages, being a stronger reducing agent and highly soluble in ethers, whilst remaining safer to handle than lithium aluminium hydride.
In nitrile reduction a nitrile is reduced to either an amine or an aldehyde with a suitable chemical reagent.
In organic chemistry, carbonyl reduction is the conversion of any carbonyl group, usually to an alcohol. It is a common transformation that is practiced in many ways. Ketones, aldehydes, carboxylic acids, esters, amides, and acid halides - some of the most pervasive functional groups, -comprise carbonyl compounds. Carboxylic acids, esters, and acid halides can be reduced to either aldehydes or a step further to primary alcohols, depending on the strength of the reducing agent. Aldehydes and ketones can be reduced respectively to primary and secondary alcohols. In deoxygenation, the alcohol group can be further reduced and removed altogether by replacement with H.
Carbon nanotube supported catalyst is a novel supported catalyst, using carbon nanotubes as the support instead of the conventional alumina or silicon support. The exceptional physical properties of carbon nanotubes (CNTs) such as large specific surface areas, excellent electron conductivity incorporated with the good chemical inertness, and relatively high oxidation stability makes it a promising support material for heterogeneous catalysis.
Urushibara nickel is a nickel-based hydrogenation catalyst. It is a heterogeneous catalyst, comparable to Raney nickel. Urushibara nickel is however not pyrophoric. For most hydrogenations, it performs comparably to W-7 grade Raney nickel.
Nickel boride is the common name of materials composed chiefly of the elements nickel and boron that are widely used as catalysts in organic chemistry. Their approximate chemical composition is Ni2.5B, and they are often incorrectly denoted "Ni
2B" in organic chemistry publications.
Cobalt(II) selenide is an inorganic compound with the chemical formula CoSe. The mineral form of this compound is known as freboldite. Similar minerals include trogtalite (CoSe2) and bornhardtite (Co2+Co3+2Se4).
Iron boride refers to various inorganic compounds with the formula FexBy. Two main iron borides are FeB and Fe2B. Some iron borides possess useful properties such as magnetism, electrical conductivity, corrosion resistance and extreme hardness. Some iron borides have found use as hardening coatings for iron. Iron borides have properties of ceramics such as high hardness, and properties of metal properties, such as thermal conductivity and electrical conductivity. Boride coatings on iron are superior mechanical, frictional, and anti-corrosive. Iron monoboride (FeB) is a grey powder that is insoluble in water. FeB is harder than Fe2B, but is more brittle and more easily fractured upon impact.
Nanoclusters are atomically precise, crystalline materials most often existing on the 0-2 nanometer scale. They are often considered kinetically stable intermediates that form during the synthesis of comparatively larger materials such as semiconductor and metallic nanocrystals. The majority of research conducted to study nanoclusters has focused on characterizing their crystal structures and understanding their role in the nucleation and growth mechanisms of larger materials.
Dinickel boride is a chemical compound of nickel and boron with formula Ni
2B. It is one of the borides of nickel.
Trinickel boride is a compound of nickel and boron with chemical formula Ni
3B. It is one of the borides of nickel.