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Nickel Difluoride
Nickel(II) fluoride is the chemical compound with the formula NiF2. It is an ionic compound of nickel and fluorine and forms yellowish to green tetragonal crystals. Unlike many fluorides, NiF2 is stable in air. Nickel(II) fluoride is also produced when nickel metal is exposed to fluorine. In fact, NiF2 comprises the passivating surface that forms on nickel alloys (e.g. monel) in the presence of hydrogen fluoride or elemental fluorine. For this reason, nickel and its alloys are suitable materials for storage and transport these fluorine and related fluorinating agents. NiF2 is also used as a catalyst for the synthesis of chlorine pentafluoride. Preparation and structure NiF2 is prepared by treatment of anhydrous nickel(II) chloride with fluorine at 350 °C: :NiCl2 + F2 → NiF2 + Cl2 The corresponding reaction of cobalt(II) chloride results in oxidation of the cobalt, whereas nickel remains in the +2 oxidation state after fluorination because its +3 oxidation state i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethanol
Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the pseudoelement symbol for ethyl group, ethyl. Ethanol is a Volatility (chemistry), volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. As a psychoactive depressant, it is the active ingredient in alcoholic beverages, and the second most consumed drug globally behind caffeine. Ethanol is naturally produced by the fermentation process of sugars by yeasts or via petrochemical processes such as ethylene hydration. Historically it was used as a general anesthetic, and has modern medical applications as an antiseptic, disinfectant, solvent for some medications, and antidote for methanol poisoning and ethylene glycol poisoning. It is used as a chemical solvent and in the Chemical synthesis, synthesis of orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Fluoride
Hydrogen fluoride (fluorane) is an Inorganic chemistry, inorganic compound with chemical formula . It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluorine, often in the form of hydrofluoric acid, and is an important feedstock in the preparation of many important compounds including pharmaceuticals and polymers such as polytetrafluoroethylene (PTFE). HF is also widely used in the petrochemical industry as a component of superacids. Due to strong and extensive hydrogen bonding, it boils near room temperature, a much higher temperature than other hydrogen halides. Hydrogen fluoride is an extremely dangerous gas, forming corrosive and penetrating hydrofluoric acid upon contact with moisture. The gas can also cause blindness by rapid destruction of the corneas. History In 1771 Carl Wilhelm Scheele prepared the aqueous solution, hydrofluoric acid in large quantities, although hydrofluoric acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel Compounds
Nickel compounds are chemical compounds containing the element nickel which is a member of the group 10 of the periodic table. Most compounds in the group have an oxidation state of +2. Nickel is classified as a transition metal with nickel(II) having much chemical behaviour in common with iron(II) and cobalt(II). Many salts of nickel(II) are isomorphous with salts of magnesium due to the ionic radii of the cations being almost the same. Nickel forms many coordination complexes. Nickel tetracarbonyl was the first pure metal carbonyl produced, and is unusual in its volatility. Metalloproteins containing nickel are found in biological systems. Nickel forms simple binary compounds with non metals including halogens, chalcogenides, and pnictides. Nickel ions can act as a cation in salts with many acids, including common oxoacids. Salts of the hexaaqua ion (Ni2+) are especially well known. Many double salts containing nickel with another cation are known. There are organic acid sal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel(II) Hydroxide
Nickel(II) hydroxide is the inorganic compound with the formula Ni(OH)2. It is a lime-green solid that dissolves with decomposition in ammonia and amines and is attacked by acids. It is electroactive, being converted to the Ni(III) oxy-hydroxide, leading to widespread applications in rechargeable batteries. Properties Nickel(II) hydroxide has two well-characterized polymorphs, α and β. The α structure consists of Ni(OH)2 layers with intercalated anions or water. The β form adopts a hexagonal close-packed structure of Ni2+ and OH− ions. In the presence of water, the α polymorph typically recrystallizes to the β form. In addition to the α and β polymorphs, several γ nickel hydroxides have been described, distinguished by crystal structures with much larger inter-sheet distances. The mineral form of Ni(OH)2, theophrastite, was first identified in the Vermion region of northern Greece, in 1980. It is found naturally as a translucent emerald-green crystal formed in thin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base (chemistry)
In chemistry, there are three definitions in common use of the word "base": '' Arrhenius bases'', '' Brønsted bases'', and '' Lewis bases''. All definitions agree that bases are substances that react with acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...s, as originally proposed by Guillaume-François Rouelle, G.-F. Rouelle in the mid-18th century. In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form hydroxide ions OH−. These ions can react with Hydron (chemistry), hydrogen ions (H+ according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction. A base was therefore a metal hydroxide such as NaOH or Calcium hydroxide, Ca(OH)2. Such aqueous hydroxide solutions were also described by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Tetrafluoronickelate
Potassium tetrafluoronickelate is the inorganic compound with the formula K2NiF4. It features octahedral (high spin) Ni centers with Ni-F bond lengths of 2.006 Å. This green solid is a salt of tetrafluoronickelate. It is prepared by melting a mixture of nickel(II) fluoride, potassium fluoride, and potassium bifluoride. The compound adopts a perovskite-like structure consisting of layers of octahedral Ni centers interconnected by doubly bridging fluoride ligands. The layers are interconnected by potassium cations. It is one of the principal Ruddlesden-Popper phases. Early discoveries on cuprate superconductors focused on compounds with structures closely related to K2NiF4, e.g. lanthanum cuprate and derivative lanthanum barium copper oxide. References [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rutile
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite. Rutile has one of the highest refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large birefringence and high dispersion. Owing to these properties, it is useful for the manufacture of certain optical elements, especially polarization optics, for longer visible and infrared wavelengths up to about 4.5 micrometres. Natural rutile may contain up to 10% iron and significant amounts of niobium and tantalum. Rutile derives its name from the Latin ('red'), in reference to the deep red color observed in some specimens when viewed by transmitted light. Rutile was first described in 1803 by Abraham Gottlob Werner using specimens obtained in Horcajuelo de la Sierra, Madrid (Spain), which is consequently the type locality. Occurrence Rutile is a comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation State
In chemistry, the oxidation state, or oxidation number, is the hypothetical Electrical charge, charge of an atom if all of its Chemical bond, bonds to other atoms are fully Ionic bond, ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state may be positive, negative or zero. Beside nearly-pure ionic bonding, many covalent bonds exhibit a strong ionicity, making oxidation state a useful predictor of charge. The oxidation state of an atom does not represent the "real" charge on that atom, or any other actual atomic property. This is particularly true of high oxidation states, where the ionization energy required to produce a multiply positive ion is far greater than the energies available in chemical reactions. Additionally, the oxidation states of atoms in a given compound may vary depending on Electronegativities of the elements (data page), the choice of electronegativity scale used in their calculation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt
Cobalt is a chemical element; it has Symbol (chemistry), 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, somewhat brittle, gray metal. Cobalt-based blue pigments (cobalt blue) have been used since antiquity for jewelry and paints, and to impart a distinctive blue tint to glass. The color was long thought to be due to the metal bismuth. Miners had long used the name ''kobold ore'' (German language, 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 off 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), which was ultimately named for the ''kobold''. Today, some cobalt is produced sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. The oxidation and reduction processes occur simultaneously in the chemical reaction. There are two classes of redox reactions: * Electron-transfer – Only one (usually) electron flows from the atom, ion, or molecule being oxidized to the atom, ion, or molecule that is reduced. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * Atom transfer – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously, the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt(II) Chloride
Cobalt(II) chloride is an inorganic compound, a salt of cobalt and chlorine, with the formula . The compound forms several hydrates ·''n'', for ''n'' = 1, 2, 6, and 9. Claims of the formation of tri- and tetrahydrates have not been confirmed.M. T. Saugier, M. Noailly, R. Cohen-Adad, F. Paulik, and J. Paulik (1977): "Equilibres solide ⇄ liquide ⇆ vapeur du systeme binaire -" ''Journal of Thermal Analysis'', volume 11, issue 1, pages 87–100. Note: the lowest point of fig.6 is inconsistent with fig.7; probably should be at -27.8 C instead of 0 C. The anhydrous form is a blue crystalline solid; the dihydrate is purple and the hexahydrate is pink. Commercial samples are usually the hexahydrate, which is one of the most commonly used cobalt salts in the lab. Properties Anhydrous At room temperature, anhydrous cobalt chloride has the cadmium chloride structure () (Rm) in which the cobalt(II) ions are octahedrally coordinated. At about 706 °C (20 degrees below the melting ... [...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 Large scale production and uses of nickel chloride are associated with the purification of nickel from its ores. It is generated upon extraction nickel matte and residues obtained from roasting refining nickel-containing ores using hydrochloric acid. Electrolysis of nickel chloride solutions are used in the production of nickel metal. Other significant routes to nickel chloride arise from processing of ore concentrates such as various reactions involving copper chlorides: : : Labo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
