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Methyl Halide
The monohalomethanes are organic compounds in which a hydrogen atom in methane is replaced by a halogen. They belong to the haloalkanes or to the subgroup of halomethanes. The four common members are fluoromethane, chloromethane, bromomethane and iodomethane. Historical name for this group is methyl halides; it's still widely used. The compounds of this class are often described as or MeX (X - any halogen, Me - methyl group). Related compounds There are analogs with more than one hydrogen atom in methane is replaced by a halogen: * Dihalomethane, , two hydrogen atoms replaced * Trihalomethane, , three hydrogen atoms replaced * Tetrahalomethane, , all four hydrogen atoms replaced Analogs with carbon atom replaced with a heavier group 14 element are also known: * Monohalosilane, (with silicon, related to silane) * Monohalogermane, (with germanium, related to germane) * Monohalostannane, (with tin, related to stannane) See also * Methyl halide transferase, an enzyme produc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Formula
The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are connected to one another. The chemical bonding within the molecule is also shown, either explicitly or implicitly. Unlike other chemical formula types, which have a limited number of symbols and are capable of only limited descriptive power, structural formulas provide a more complete geometric representation of the molecular structure. For example, many chemical compounds exist in different isomeric forms, which have different enantiomeric structures but the same molecular formula. There are multiple types of ways to draw these structural formulas such as: Lewis structures, condensed formulas, skeletal formulas, Newman projections, Cyclohexane conformations, Haworth projections, and Fischer projections. Several systematic chemical naming formats, as in chemical databases, are used that are equivalent to, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halogen
The halogens () are a group in the periodic table consisting of six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and the radioactive elements astatine (At) and tennessine (Ts), though some authors would exclude tennessine as its chemistry is unknown and is theoretically expected to be more like that of gallium. In the modern IUPAC nomenclature, this group is known as group 17. The word "halogen" means "salt former" or "salt maker". When halogens react with metals, they produce a wide range of salts, including calcium fluoride, sodium chloride (common table salt), silver bromide and potassium iodide. The group of halogens is the only periodic table group that contains elements in three of the main states of matter at standard temperature and pressure, though not far above room temperature the same becomes true of groups 1 and 15, assuming white phosphorus is taken as the standard state.This could also be the case for group 12, al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon
Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Silicon is a significant element that is essential for several physiological and metabolic processes in plants. Silicon is widely regarded as the predominant semiconductor material due to its versatile applications in various electrical devices such as transistors, solar cells, integrated circuits, and others. These may be due to its significant band gap, expansive optical transmission range, extensive absorption spectrum, surface roughening, and effective anti-reflection coating. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group 14 Element
The carbon group is a periodic table group consisting of carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). It lies within the p-block. In modern IUPAC notation, it is called group 14. In the field of semiconductor physics, it is still universally called group IV. The group is also known as the tetrels (from the Greek word ''tetra'', which means four), stemming from the Roman numeral IV in the group name, or (not coincidentally) from the fact that these elements have four valence electrons (see below). They are also known as the crystallogens or adamantogens. Characteristics Chemical Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior: Each of the elements in this group has 4 electrons in its outer shell. An isolated, neutral group 14 atom has the ns2 np2 configuration in the ground state. These elements, especially c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahalomethane
Tetrahalomethanes are fully halogenated methane derivatives of general formula CFkCllBrmInAtp, where:k+l+m+n+p=4Tetrahalomethanes are on the border of inorganic and organic chemistry, thus they can be assigned both inorganic and organic names by IUPAC: tetrafluoromethane - carbon tetrafluoride, tetraiodomethane - carbon tetraiodide, dichlorodifluoromethane - carbon dichloride difluoride. Each halogen ( F, Cl, Br, I, At) forms a corresponding halomethane, but their stability decreases in order CF4 > CCl4 > CBr4 > CI4 from exceptionally stable gaseous tetrafluoromethane with bond energy 515 kJ·mol−1 to solid tetraiodomethane, depending on bond energy. Many mixed halomethanes are also known, such as CBrClF2. Uses Fluorine, chlorine, and sometimes bromine-substituted halomethanes were used as refrigerants, commonly known as CFCs (chlorofluorocarbon Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly Halogenation, halogenated hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trihalomethane
In chemistry, trihalomethanes (THMs) are chemical compounds in which three of the four hydrogen atoms of methane () are replaced by halogen atoms. Trihalomethanes with all the same halogen atoms are called haloforms. Many trihalomethanes find uses in industry as solvents or refrigerants. Some THMs are also environmental pollutants, and a few are considered carcinogenic. Table of common trihalomethanes Industrial uses Only chloroform has significant applications of the haloforms. In the predominant application, chloroform is required for the production of tetrafluoroethylene (TFE), precursor to teflon. Chloroform is fluorinated by reaction with hydrogen fluoride to produce chlorodifluoromethane (R-22). Pyrolysis of chlorodifluoromethane (at 550-750 °C) yields TFE, with difluorocarbene as an intermediate. :CHCl3 + 2 HF -> CHClF2 + 2 HCl :2 CHClF2 -> C2F4 + 2 HCl Refrigerants and solvents Trihalomethanes released to the environment break down faster than chlorofluorocarbons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihalomethane
The dihalomethanes are organic compounds in which two hydrogen atoms in methane are replaced by halogen atoms. They belong to the haloalkanes, specifically the subgroup of halomethanes, and contains ten members. There are four members with only one kind of halogen atom: difluoromethane, dichloromethane, dibromomethane and diiodomethane. There are six members with two kinds of halogen atoms: * Bromochloromethane Bromochloromethane or methylene bromochloride and Halon 1011 is a mixed halomethane. It is a heavy low-viscosity liquid with refractive index 1.4808. Halon 1011 was invented for use in fire extinguishers in Germany during the mid-1940s, in an atte ... * Bromofluoromethane * Bromoiodomethane * Chlorofluoromethane * Chloroiodomethane * Fluoroiodomethane References See also * Monohalomethane * Trihalomethane * Tetrahalomethane {{Commons category, Dihalomethanes Chemical substances ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Group
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula (whereas normal methane has the formula ). In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many organic compounds. It is a very stable group in most molecules. While the methyl group is usually part of a larger molecule, bonded to the rest of the molecule by a single covalent bond (), it can be found on its own in any of three forms: methanide anion (), methylium cation () or methyl radical (). The anion has eight valence electrons, the radical seven and the cation six. All three forms are highly reactive and rarely observed. Methyl cation, anion, and radical Methyl cation The methylium cation () exists in the gas phase, but is otherwise not encountered. Some compounds are considered to be sources of the cation, and this simplification is used pervasively in organic chemistry. For ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodomethane
Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one hydrogen atom by an atom of iodine. It is naturally emitted in small amounts by rice plantations. It is also produced in vast quantities estimated to be greater than 214,000 tons annually by algae and kelp in the world's temperate oceans, and in lesser amounts on land by terrestrial fungi and bacteria. It is used in organic synthesis as a source of methyl groups. Preparation and handling Iodomethane is formed via the exothermic reaction that occurs when iodine is added to a mixture of methanol with red phosphorus. The iodinating reagent is phosphorus triiodide that is formed ''in situ:'' :3 CH3OH + PI3 → 3 CH3I + H2PO3H Alternatively, it is prepared from the reaction of dimethyl sulfate with potassium iodide in the presence of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromomethane
Bromomethane, commonly known as methyl bromide, is an organobromine compound with formula C H3 Br. This colorless, odorless, nonflammable gas is produced both industrially and biologically. It is a recognized ozone-depleting chemical. According to the IPCC Fifth Assessment Report, it has a global warming potential of 2. The compound was used extensively as a pesticide until being phased out by most countries in the early 2000s. From a chemistry perspective, it is one of the halomethanes. Occurrence and manufacture Marine organisms are estimated to produce 56,000 tonnes annually. It is also produced in small quantities by certain terrestrial plants, such as members of the family Brassicaceae. In 2009, an estimated 24,000 tonnes of methyl bromide were produced. Its production was curtailed by the Montreal Protocol, such that in 1983, production was nearly twice that of 2009 levels. It is manufactured by treating methanol with bromine in the presence of sulfur or hydrogen sulf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloromethane
Chloromethane, also called methyl chloride, Refrigerant-40, R-40 or HCC 40, is an organic compound with the chemical formula . One of the haloalkanes, it is a colorless, sweet-smelling, flammable gas. Methyl chloride is a crucial reagent in industrial chemistry, although it is rarely present in consumer products, and was formerly utilized as a refrigerant. Most chloromethane is biogenic. Occurrence Chloromethane is an abundant organohalogen, anthropogenic or natural, in the atmosphere. Natural sources produce an estimated 4,100,000,000 kg/yr. Marine Laboratory cultures of marine phytoplankton (''Phaeodactylum tricornutum'', ''Phaeocystis'' sp., ''Thalassiosira weissflogii'', ''Chaetoceros calcitrans'', ''Isochrysis'' sp., ''Porphyridium'' sp., ''Synechococcus'' sp., ''Tetraselmis'' sp., ''Prorocentrum'' sp., and ''Emiliana huxleyi'') produce CH3Cl, but in relatively insignificant amounts. An extensive study of 30 species of polar macroalgae revealed the release of significant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluoromethane
Fluoromethane, also known as methyl fluoride, Freon 41, Halocarbon-41 and HFC-41, is a non-toxic, liquefiable, and flammable gas at standard temperature and pressure. It is made of carbon, hydrogen, and fluorine. The name stems from the fact that it is methane (CH4) with a fluorine atom substituted for one of the hydrogen atoms. It is used in semiconductor manufacturing processes as an etching gas in plasma etch reactors. Fluoromethane (originally called "fluorohydrate of methylene") became the first organofluorine compound to be discovered when it was synthesized by French chemists Jean-Baptiste Dumas and Eugène-Melchior Péligot in 1835 by distilling dimethyl sulfate with potassium fluoride. Composition The compound is the lowest mass member of the hydrofluorocarbon (HFC) family, compounds which contain only hydrogen, fluorine, and carbon. These compounds are related to the chlorofluorocarbons (CFC), but since they do not contain chlorine, are not destructive to the ozone l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
