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Nickel Boride
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 "" in organic chemistry publications. Nickel boride catalysts are typically prepared by reacting a salt of nickel with sodium borohydride. The composition and properties vary depending on the specific preparation method. The two most common forms, described and evaluated in detail by Herbert C. Brown and Charles Allan Brown in 1963, are known as P−1 nickel and P−2 nickel. These catalysts are usually obtained as black granules (P−1) or colloidal suspensions (P−2). They are air-stable, non-magnetic and non-pyrophoric, but slowly react with water to form nickel hydroxide . They are insoluble in all solvents, but react with concentrated mineral acids. They are claimed to be more effective hydrogenation catalysts than Raney nickel. Histo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to react with air under standard conditions because a passivation layer of nickel oxide forms on the surface that prevents further corrosion. Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere. Meteoric nickel is found in combination with iron, a reflection of the origin of those elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's outer and inner cores. Use of nickel (as natural meteoric nickel–iron alloy) has been traced as far back as 3500 BCE. Nickel was first isolated and classified as an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt
Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal. Cobalt-based blue pigments ( cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was for a long time thought to be due to the known metal bismuth. Miners had long used the name ''kobold ore'' (German for ''goblin ore'') for some of the blue-pigment-producing minerals; they were so named because they were poor in known metals, and gave poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), and this was ultimately named for the ''kobold''. Today, some cobalt is produced specifically from one of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Diffraction
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, and various other information. Since many materials can form crystals—such as salts, metals, minerals, semiconductors, as well as various inorganic, organic, and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences among various mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel Chloride
Nickel(II) chloride (or just nickel chloride) is the chemical compound NiCl2. The anhydrous salt is yellow, but the more familiar hydrate NiCl2·6H2O is green. Nickel(II) chloride, in various forms, is the most important source of nickel for chemical synthesis. The nickel chlorides are deliquescent, absorbing moisture from the air to form a solution. Nickel salts have been shown to be carcinogenic to the lungs and nasal passages in cases of long-term inhalation exposure. Production and syntheses The largest scale production of nickel chloride involves the extraction with hydrochloric acid of nickel matte and residues obtained from roasting refining nickel-containing ores. Nickel chloride is not usually prepared in the laboratory because it is inexpensive and has a long shelf-life. Heating the hexahydrate in the range 66–133.°C gives the yellowish dihydrate, NiCl2·2H2O. The hydrates convert to the anhydrous form upon heating in thionyl chloride or by heating under a stre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a hydroxyl group). Ethanol is a Volatility (chemistry), volatile, Combustibility and flammability, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. It is a psychoactive recreational drug, the active ingredient in alcoholic drinks. Ethanol is naturally produced by the fermentation process of Carbohydrate, sugars by yeasts or via Petrochemistry, petrochemical processes such as ethylene hydration. It has medical applications as an antiseptic and disinfectant. It is used as a chemical solvent and in the Chemical synthesis, synthesis of organic compounds, and as a Alcohol fuel, fuel source. Ethanol also can be dehydrated to make ethylene, an important chemical feedstock. As of 2006, world produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is 23Na. The free metal does not occur in nature, and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and halite (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans. Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful sodium compounds, sodium hydroxide (lye) is used in soap manufacture, and sodium chloride (edible salt) is a de-icing agent and a nutrient for animals including h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electroless Nickel-boron Plating
Electroless nickel-boron coating (often called NiB coating) is a metal plating process that can create a layer of a nickel- boron alloy on the surface of a solid substrate, like metal or plastic. The process involves dipping the substrate in a water solution containing nickel salt and a boron-containing reducing agent, such as an alkylamineborane or sodium borohydride. It is a type of electroless nickel plating. A similar process, that uses a hypophosphite as a reducing agent, yields a nickel-phosphorus coating instead. Unlike electroplating, electroless plating processes in general not require passing an electric current through the bath and the substrate; the reduction of the metal cations in solution to metallic is achieved by purely chemical means, through an autocatalytic reaction. Thus electroless plating creates an even layer of metal regardless of the geometry of the surface – in contrast to electroplating which suffers from uneven current density due to the effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel(II) Acetate
Nickel(II) acetate is the name for the coordination compounds with the formula Ni(CH3CO2)2·x H2O where x can be 0, 2, and 4. The green tetrahydrate Ni(CH3CO2)2·4 H2O is most common. It is used for electroplating. Synthesis and structure The compound can be prepared by treating nickel or nickel(II) carbonate with acetic acid: :NiCO3 + 2 CH3CO2H + 3 H2O → Ni(CH3CO2)2·4 H2O + CO2 The green tetrahydrate has been shown by X-ray crystallography to adopt an octahedral structure, the central nickel centre being coordinated by four water molecules and two acetate ligand In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's elec ...s. It may be dehydrated ''in vacuo'', by reaction with acetic anhydride or by heat. Safety Nickel salts are carcinogenic and irritate the skin. References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel(II) Nitrate
Nickel nitrate is the inorganic compound Ni(NO3)2 or any hydrate thereof. The anhydrous form is not commonly encountered, thus "nickel nitrate" usually refers to nickel(II) nitrate hexahydrate. The formula for this species is written in two ways: Ni(NO3)2.6H2O and, more descriptively i(H2O)6NO3)2. The latter formula indicates that the nickel(II) center is surrounded by six water molecules in this hydrated salt. In the hexahydrate, the nitrate anions are not bonded to nickel. Also known are three other hydrates: Ni(NO3)2.9H2O, Ni(NO3)2.4H2O, and Ni(NO3)2.2H2O. Anhydrous Ni(NO3)2 is also known. It is prepared by the reaction of nickel oxide with nitric acid: : NiO + 2 HNO3 + 5 H2O → Ni(NO3)2.6H2O The anhydrous nickel nitrate is typically not prepared by the heating the hydrates. Rather is generated by reaction of hydrates with dinitrogen pentoxide or of nickel carbonyl with dinitrogen tetroxide: : Ni(CO)4 + 2 N2O4 → Ni(NO3)2 + 2 NO + 4 CO The h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel(II) Chloride
Nickel(II) chloride (or just nickel chloride) is the chemical compound NiCl2. The anhydrous salt is yellow, but the more familiar hydrate NiCl2·6H2O is green. Nickel(II) chloride, in various forms, is the most important source of nickel for chemical synthesis. The nickel chlorides are deliquescent, absorbing moisture from the air to form a solution. Nickel salts have been shown to be carcinogenic to the lungs and nasal passages in cases of long-term inhalation exposure. Production and syntheses The largest scale production of nickel chloride involves the extraction with hydrochloric acid of nickel matte and residues obtained from roasting refining nickel-containing ores. Nickel chloride is not usually prepared in the laboratory because it is inexpensive and has a long shelf-life. Heating the hexahydrate in the range 66–133.°C gives the yellowish dihydrate, NiCl2·2H2O. The hydrates convert to the anhydrous form upon heating in thionyl chloride or by heating under a stream ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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