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Osmium Compounds
Osmium compounds are compounds containing the element osmium (Os). Osmium forms compounds with oxidation states ranging from −2 to +8. The most common oxidation states are +2, +3, +4, and +8. The +8 oxidation state is notable for being the highest attained by any chemical element aside from iridium's +9 and is encountered only in xenon, ruthenium, hassium, iridium, and plutonium. The oxidation states −1 and −2 represented by the two reactive compounds and are used in the synthesis of osmium Cluster chemistry#Transition metal carbonyl clusters, cluster compounds. Oxides Osmium tetroxide is the most notable compound of osmium, having many uses. The name "osmium" even derives from Ancient Greek, Greek "" because of the smell of osmium tetroxide. It also has a number of unusual properties, one being that the solid is Volatility (chemistry), volatile. Its volatility, along with its strong oxidizing power, is the origin of its quite serious toxicity - inhalation provides a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triosmium Dodecacarbonyl
Triosmium dodecacarbonyl is a chemical compound with the formula Os3(CO)12. This yellow-colored metal carbonyl cluster is an important precursor to organo-osmium compounds. Many of the advances in cluster chemistry have arisen from studies on derivatives of Os3(CO)12 and its lighter analogue Ru3(CO)12. Structure and synthesis The cluster has D3h symmetry, consisting of an equilateral triangle of Os atoms, each of which bears two axial and two equatorial CO ligands. Each of the three osmium centers has an octahederal structure with four CO ligands and the other two osmium atoms. The Os–Os bond distance is 2.88 Å (288 pm). Ru3(CO)12 has the same structure, whereas Fe3(CO)12 is different, with two bridging CO ligands resulting in C2v symmetry. In solution, is fluxional as indicated by 13C NMR measurements. The barrier is estimated at 70 kJ/mol Os3(CO)12 is prepared by the direct reaction of OsO4 with carbon monoxide at 175 °C under high pressures: : 3 OsO4 + ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lewis Acid
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any species that has a filled orbital containing an electron pair which is not involved in bonding but may form a dative bond with a Lewis acid to form a Lewis adduct. For example, NH3 is a Lewis base, because it can donate its lone pair of electrons. Trimethylborane CH3)3Bis a Lewis acid as it is capable of accepting a lone pair. In a Lewis adduct, the Lewis acid and base share an electron pair furnished by the Lewis base, forming a dative bond. In the context of a specific chemical reaction between NH3 and Me3B, a lone pair from NH3 will form a dative bond with the empty orbital of Me3B to form an adduct NH3•BMe3. The terminology refers to the contributions of Gilbert N. Lewis. From p. 142: "We are inclined to think of substances as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrido Complex
Metal nitrido complexes are coordination compounds and metal clusters that contain an atom of nitrogen bound only to transition metals. These compounds are ''molecular'', i.e. discrete in contrast to the polymeric, dense nitride materials that are useful in materials science. The distinction between the molecular and solid-state polymers is not always very clear as illustrated by the materials Li6MoN4 and more condensed derivatives such as Na3MoN3. Transition metal nitrido complexes have attracted interest in part because it is assumed that nitrogen fixation proceeds via nitrido intermediates. Nitrido complexes have long been known, the first example being salts of sO3Nsup>−, described in the 19th century. Structural trends Mononuclear complexes feature terminal nitride ligands, typically with short M-N distances consistent with metal ligand multiple bonds. For example, in the anion in PPh4 oNCl4 the Mo-N distance is 163.7 pm. The occurrence of terminal nitrido ligands fo ... [...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] |
Imido
In organic chemistry, an imide is a functional group consisting of two acyl groups bound to nitrogen. The compounds are structurally related to acid anhydrides, although imides are more resistant to hydrolysis. In terms of commercial applications, imides are best known as components of high-strength polymers, called polyimides. Inorganic imides are also known as solid state or gaseous compounds, and the imido group (=NH) can also act as a ligand. Examples Simple example is diacetamide with the formula , formally the diacetylated derivative of ammonia. Commonly encountered imides, however, are cyclic, being derived from dicarboxylic acids. A common example is succinimide derived from succinic acid and ammonia. The names of these cyclic imides reflect the parent acid. Many imides are derived from primary amines as opposed to ammonia. These are indicated by ''N''-substituent in the prefix. For example, N-ethylsuccinimide is derived from succinic acid and ethylamine. : Propert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tert-Butylamine
''tert''-Butylamine (also erbumine and other names) is an organic chemical compound with the formula (CH3)3CNH2. It is a colorless liquid with a typical amine-like odor. ''tert''-Butylamine is one of the four isomeric amines of butane, the others being ''n''-butylamine, ''sec''-butylamine and isobutylamine. Preparation ''tert''-Butylamine is produced commercially by direct amination of isobutylene using zeolite catalysts: :NH3 + CH2=C(CH3)2 → H2NC(CH3)3 The Ritter reaction of isobutene with hydrogen cyanide is not useful because it produces too much waste. :(CH3)2C=CH2 + HCN + H2O → (CH3)3CNHCHO :(CH3)3CNHCHO + H2O → (CH3)3CNH2 + HCO2H In the laboratory, it can be prepared by the hydrogenolysis of 2,2-dimethylethylenimine, or via ''tert''-butylphthalimide. Uses ''tert''-Butylamine is used as an intermediate in the preparation of the sulfenamides such as ''N''-''tert''-butyl-2-benzothiazylsulfenamide and ''N''-''tert''-butyl-2-benzothiazylsulfeni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solution (chemistry)
In chemistry, a solution is defined by IUPAC as "A liquid or solid phase containing more than one substance, when for convenience one (or more) substance, which is called the solvent, is treated differently from the other substances, which are called solutes. When, as is often but not necessarily the case, the sum of the mole fractions of solutes is small compared with unity, the solution is called a dilute solution. A superscript attached to the ∞ symbol for a property of a solution denotes the property in the limit of infinite dilution." One important parameter of a solution is the concentration, which is a measure of the amount of solute in a given amount of solution or solvent. The term " aqueous solution" is used when one of the solvents is water. Types ''Homogeneous'' means that the components of the mixture form a single phase. ''Heterogeneous'' means that the components of the mixture are of different phase. The properties of the mixture (such as concentration, temp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buffer Solution
A buffer solution is a solution where the pH does not change significantly on dilution or if an acid or base is added at constant temperature. Its pH changes very little when a small amount of strong acid or base is added to it. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. In nature, there are many living systems that use buffering for pH regulation. For example, the bicarbonate buffering system is used to regulate the pH of blood, and bicarbonate also acts as a buffer in the ocean. Principles of buffering Buffer solutions resist pH change because of a chemical equilibrium between the weak acid HA and its conjugate base A−: When some strong acid is added to an equilibrium mixture of the weak acid and its conjugate base, hydrogen ions (H+) are added, and the equilibrium is shifted to the left, in accordance with Le Chatelier's principle. Because of this, the hydrogen ion concentration increas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahydrofuran
Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water- miscible organic liquid with low viscosity. It is mainly used as a precursor to polymers. Being polar and having a wide liquid range, THF is a versatile solvent. It is an isomer of another solvent, butanone. Production About 200,000 tonnes of tetrahydrofuran are produced annually. The most widely used industrial process involves the acid-catalyzed dehydration of 1,4-Butanediol, 1,4-butanediol. Ashland Inc., Ashland/ISP is one of the biggest producers of this chemical route. The method is similar to the production of diethyl ether from ethanol. The butanediol is derived from Condensation reaction, condensation of acetylene with formaldehyde followed by hydrogenation. DuPont developed a process for producing THF by oxidizing Butane#Isomers, ''n''-butane to crude maleic anhydride, follow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexamine
Hexamethylenetetramine (HMTA), also known as 1,3,5,7-tetraazaadamantane, is a heterocyclic organic compound with diverse applications. It has the chemical formula (CH2)6N4 and is a white crystalline compound that is highly soluble in water and polar organic solvents. It is useful in the synthesis of other organic compounds, including plastics, pharmaceuticals, and rubber additives. The compound is also used medically for certain conditions. It sublimes in vacuum at 280°C. It has a tetrahedral cage-like structure similar to adamantane. The four vertices are occupied by nitrogen atoms, which are linked by methylene groups. Although the molecular shape defines a cage, no void space is available at the interior. Synthesis, structure, reactivity Hexamethylenetetramine was discovered by Aleksandr Butlerov in 1859. In this article, Butlerov discovered formaldehyde, which he called "dioxymethylen" (methylene dioxide) age 247because his empirical formula for it was incorrect (C4H4O4) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complexation
A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many metal-containing compounds, especially those that include transition metals (elements like titanium that belong to the periodic table's d-block), are coordination complexes. Nomenclature and terminology Coordination complexes are so pervasive that their structures and reactions are described in many ways, sometimes confusingly. The atom within a ligand that is bonded to the central metal atom or ion is called the donor atom. In a typical complex, a metal ion is bonded to several donor atoms, which can be the same or different. A polydentate (multiple bonded) ligand is a molecule or ion that bonds to the central atom through several of the ligand's atoms; ligands with 2, 3, 4 or even 6 bonds to the central ato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amine
In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of electrons. Amines can also exist as hetero cyclic compounds. Aniline is the simplest aromatic amine, consisting of a benzene ring bonded to an amino group. Amines are classified into three types: primary (1°), secondary (2°), and tertiary (3°) amines. Primary amines (1°) contain one alkyl or aryl substituent and have the general formula RNH2. Secondary amines (2°) have two alkyl or aryl groups attached to the nitrogen atom, with the general formula R2NH. Tertiary amines (3°) contain three substituent groups bonded to the nitrogen atom, and are represented by the formula R3N. The functional group present in primary amines is called the amino group. Classification of amines Amines can be classified according to the nature and number o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
