what is the name of the 4th halogen
Bromine
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a halogen, never existing in pure form in nature. Bromine is barely liquid at room temperature, boiling at about 330 kelvins. Bromine is also quite toxic and corrosive, but bromide ions, which are relatively inert, can be found in halite, or table salt. Bromine is often used as a fire retardant because many compounds can be made to release free bromine atoms. Krypton (Kr) is a noble gas, placed under argon and over xenon. Being a noble gas, krypton rarely interacts with itself or other elements; although compounds have been detected, they are all unstable and decay rapidly, and as
Period 4 element
165480
Halogen The halogens () are a group in the periodic table consisting of five chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). The artificially created element 117 (tennessine, Ts) may also be a halogen. In the modern IUPAC nomenclature, this group is known as group 17. The symbol X is often used generically to refer to any halogen. The name "halogen" means "salt-producing". 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
Halogen
631082
Halogen lamp A halogen lamp, also known as a tungsten halogen, quartz-halogen or quartz iodine lamp, is an incandescent lamp consisting of a tungsten filament sealed into a compact transparent envelope that is filled with a mixture of an inert gas and a small amount of a halogen such as iodine or bromine. The combination of the halogen gas and the tungsten filament produces a halogen cycle chemical reaction which redeposits evaporated tungsten to the filament, increasing its life and maintaining the clarity of the envelope. For this to happen, a halogen lamp must be operated at a higher temperature
Halogen lamp
5935458
Halogenated ether A halogenated ether is a subcategory of a larger group of chemicals known as ethers. An ether is an organic chemical that contains an ether group — an oxygen atom connected to two (substituted) alkyl groups. A good example of an ether is the solvent diethyl ether. What differentiates a halogenated ether from other types of ethers is the substitution (halogenation) of one or more hydrogen atoms with a halogen atom. Halogen atoms include fluorine, chlorine, bromine, and iodine. Perhaps the most common use of halogenated ethers has been in anesthesiology. The first widely used inhalation anesthetic was
Halogenated ether
11202229
Thr and the bromine of the inhibitor. The bond distance was measured to be 2.973(4) Å. It is this O−Br halogen bond that contributes to the large potency of this inhibitor for human aldose reductase rather than aldehyde reductase. Halogen bond A halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. Comparison between hydrogen and halogen bonding: In both cases, A (the hydrogen/halogen bond acceptor) is the atom, group, or molecule that donates
Halogen bond
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atoms. If the number includes a fifth digit, the fifth number indicates the number of iodine atoms (though iodine in halon is rare). Any bonds not taken up by halogen atoms are then allocated to hydrogen atoms. For example, consider Halon 1211: C F Cl Br 1 2 1 1 Halon 1211 has one carbon atom, two fluorine atoms, one chlorine atom and one bromine atom. A single carbon only has four bonds, all of which are taken by the halogen atoms, so there is no hydrogen. Thus its formula is CF<nowiki>BrCl</nowiki>, and its IUPAC name is therefore bromochlorodifluoromethane. The
Halomethane
1811819
Halogen addition reaction A halogen addition reaction is a simple organic reaction where a halogen molecule is added to the carbon–carbon double bond of an alkene functional group. The general chemical formula of the halogen addition reaction is: (X represents the halogens bromine or chlorine, and in this case, a solvent could be CHCl or CCl). The product is a vicinal dihalide. This type of reaction is a halogenation and an electrophilic addition. The reaction mechanism for an alkene bromination can be described as follows. In the first step of the reaction, a bromine molecule approaches the electron-rich alkene carbon–carbon
Halogen addition reaction
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perspective, haloalkanes can be classified according to the connectivity of the carbon atom to which the halogen is attached. In primary (1°) haloalkanes, the carbon that carries the halogen atom is only attached to one other alkyl group. An example is chloroethane (). In secondary (2°) haloalkanes, the carbon that carries the halogen atom has two C–C bonds. In tertiary (3°) haloalkanes, the carbon that carries the halogen atom has three C–C bonds. Haloalkanes can also be classified according to the type of halogen on group 7 responding to a specific halogenoalkane. Haloalkanes containing carbon bonded to fluorine, chlorine, bromine,
Haloalkane
1811825
the group of George A. Olah obtained NMR spectra of tetramethylethylenebromonium ions by dissolving 2,3-dibromo-2,3-dimethylbutane in magic acid at −60 °C. The spectrum for the corresponding fluorine compound on the other hand was consistent with a rapidly equilibrating pair of β-fluorocarbocations. Halogen addition reaction A halogen addition reaction is a simple organic reaction where a halogen molecule is added to the carbon–carbon double bond of an alkene functional group. The general chemical formula of the halogen addition reaction is: (X represents the halogens bromine or chlorine, and in this case, a solvent could be CHCl or CCl). The product is
Halogen addition reaction
69313
name "halogen", meaning "salt producer", was originally used for chlorine in 1811 by Johann Salomo Christoph Schweigger. This term was later used as a generic term to describe all the elements in the chlorine family (fluorine, bromine, iodine), after a suggestion by Jöns Jakob Berzelius in 1826. In 1823, Michael Faraday liquefied chlorine for the first time, and demonstrated that what was then known as "solid chlorine" had a structure of chlorine hydrate (Cl·HO). Chlorine gas was first used by French chemist Claude Berthollet to bleach textiles in 1785. Modern bleaches resulted from further work by Berthollet, who first produced
Chlorine
165506
products. Chlorine also reacts with sodium to create sodium chloride, which is table salt. Halogen lamps are a type of incandescent lamp using a tungsten filament in bulbs that have a small amounts of a halogen, such as iodine or bromine added. This enables the production of lamps that are much smaller than non-halogen incandescent lightbulbs at the same wattage. The gas reduces the thinning of the filament and blackening of the inside of the bulb resulting in a bulb that has a much greater life. Halogen lamps glow at a higher temperature (2800 to 3400 kelvins) with a whiter
Halogen
9794527
directly, it is important to maximize the exposure of available surfaces which then re-emit the warmth to provide an even all round ambient warmth. Halogen lamps are incandescent lamps filled with highly pressurized inert gas. This gas is combined with a small amount of halogen gas (bromine or iodine) which causes tungsten atoms to regenerate by lessening the evaporation of the filament. This leads to a much longer life of halogen lamps than other incandescent lamps. Due to the high pressure and temperature halogen lamps produce, they are relatively small and made out of quartz glass because it has a
Infrared heater
11202209
structures. Halogen bond strengths range from 5–180 kJ/mol. The strength of XB allows it to compete with HB, which are a little bit weaker in strength. Halogen bonds tend to form at 180° angles, which was shown in Odd Hassel’s studies with bromine and 1,4-dioxane in 1954. Another contributing factor to halogen bond strength comes from the short distance between the halogen (Lewis acid, XB donor) and Lewis base (XB acceptor). The attractive nature of halogen bonds result in the distance between the donor and acceptor to be shorter than the sum of van der Waals radii. The XB interaction
Halogen bond
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the mineral fluorospar, which was used as a flux in metal working. Chlorine's name comes from the Greek word "chloros", meaning "greenish-yellow". Bromine's name comes from the Greek word "bromos", meaning "stench". Iodine's name comes from the Greek word "iodes", meaning "violet". Astatine's name comes from the Greek word "astatos", meaning "unstable". Tennessine is named after the US state of Tennessee. The halogens show trends in chemical bond energy moving from top to bottom of the periodic table column with fluorine deviating slightly. (It follows trend in having the highest bond energy in compounds with other atoms, but it has
Halogen
165496
pure halogen with a smaller interhalogen such as . All interhalogens except can be produced by directly combining pure halogens in various conditions. Interhalogens are typically more reactive than all diatomic halogen molecules except F because interhalogen bonds are weaker. However, the chemical properties of interhalogens are still roughly the same as those of diatomic halogens. Many interhalogens consist of one or more atoms of fluorine bonding to a heavier halogen. Chlorine can bond with up to 3 fluorine atoms, bromine can bond with up to five fluorine atoms, and iodine can bond with up to seven fluorine atoms. Most
Halogen
19309038
Halogen Software Halogen Software is a Canadian company that provides cloud-based talent management solutions to customers with between 100 and 10,000 employees. The firm was founded in 1996 and is headquartered in Ottawa, Ontario, Canada. The firm was formerly known as Manta Corporation and in June 2001, changed its name to Halogen Software Inc. Halogen Software has been backed by JMI Equity since 2008. Les Rechan became Halogen Software’s new President and CEO in 2015 after serving as interim CEO and on Halogen’s board of directors from May 2015. Halogen opened an office in the United Kingdom in September 2011
Halogen Software
11202206
donor accepts electrons while the halogen bond acceptor donates electrons. A parallel relationship can easily be drawn between halogen bonding and hydrogen bonding (HB). In both types of bonding, an electron donor/electron acceptor relationship exists. The difference between the two is what species can act as the electron donor/electron acceptor. In hydrogen bonding, a hydrogen atom acts as the electron acceptor and forms a non-covalent interaction by accepting electron density from an electron rich site (electron donor). In halogen bonding, a halogen atom is the electron acceptor. Simultaneously, the normal covalent bond between H or X and D weakens, so
Halogen bond
165486
with alpha particles. In 1811, the German chemist Johann Schweigger proposed that the name "halogen" – meaning "salt producer", from αλς [als] "salt" and γενειν [genein] "to beget" – replace the name "chlorine", which had been proposed by the English chemist Humphry Davy. Davy's name for the element prevailed. However, in 1826, the Swedish chemist Baron Jöns Jacob Berzelius proposed the term "halogen" for the elements fluorine, chlorine, and iodine, which produce a sea-salt-like substance when they form a compound with an alkaline metal. Fluorine's name comes from the Latin word "fluere", meaning "to flow", because it was derived from
Halogen
165517
additional electron is located in the aluminium cluster at the location directly opposite from the iodine atom. The cluster must therefore have a higher electron affinity for the electron than iodine and therefore the aluminium cluster is called a superhalogen (i.e., the vertical electron detachment energies of the moieties that make up the negative ions are larger than those of any halogen atom). The cluster component in the ion is similar to an iodide ion or a bromide ion. The related cluster is expected to behave chemically like the triiodide ion.<ref name="bergeron/2005"></ref> Halogen The halogens () are a group in
Halogen
11202205
Halogen bond A halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. Comparison between hydrogen and halogen bonding: In both cases, A (the hydrogen/halogen bond acceptor) is the atom, group, or molecule that donates electrons to the electron poor species H-D or X-D (the hydrogen or halogen bond donors respectively). H is the hydrogen atom involved in hydrogen bonding, and X is the halogen atom involved in halogen bonding. Note the halogen bond
Halogen bond
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Halogen oven A halogen oven, halogen convection oven, or halogen cooking pot is a type of oven that utilizes a halogen lamp as its heating element. It is used primarily for cooking. Halogen ovens are often noted for being more energy-efficient than a conventional oven due to their use of a halogen lamp reducing the cooking time usually needed in a conventional oven. A basic halogen oven features a heating chamber consisting of a clear glass bowl with a removable glass lid to which the heating assembly is secured. Inside the heating chamber, multi-level metal racks are used to elevate
Halogen oven
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terms of energy use, one source claims that a halogen oven uses about "half the electricity of a conventional oven and about the same as a microwave oven". In an effort to comply with the Energy Independence and Security Act of 2007, Hasbro redesigned its Easy-Bake Oven to utilize a halogen lamp for the oven's heating element in place of its less efficient conventional incandescent heating element. Halogen oven A halogen oven, halogen convection oven, or halogen cooking pot is a type of oven that utilizes a halogen lamp as its heating element. It is used primarily for cooking. Halogen
Halogen oven
4927854
Halogen dance rearrangement The halogen dance rearrangement is an organic reaction in which a halogen substituent moves to a new position on an aromatic ring system. The reaction belongs to a class of organic reactions called 1,2-rearrangements. The original halogen dance is the base-catalysed rearrangement of 1,2,4-tribromobenzene to 1,3,5-tribromobenzene in liquid ammonia with the aniline/potassium base system. The intermediate in this reaction is an aryl carbanion. The halogen dance concept can be extended from benzene derivatives to other aromatic systems as well, for instance furan and thiophene compounds. The halogen dance rearrangement of iodooxazoles was studied by the Stambuli Group.
Halogen dance rearrangement
4927853
Halogen dance rearrangement The halogen dance rearrangement is an organic reaction in which a halogen substituent moves to a new position on an aromatic ring system. The reaction belongs to a class of organic reactions called 1,2-rearrangements. The original halogen dance is the base-catalysed rearrangement of 1,2,4-tribromobenzene to 1,3,5-tribromobenzene in liquid ammonia with the aniline/potassium base system. The intermediate in this reaction is an aryl carbanion. The halogen dance concept can be extended from benzene derivatives to other aromatic systems as well, for instance furan and thiophene compounds. The halogen dance rearrangement of iodooxazoles was studied by the Stambuli Group.
Halogen dance rearrangement
11202225
version), a study by Auffinger and others on single crystals structures with 3 Å resolution or better entered into the PDB revealed that over 100 halogen bonds were found in six halogenated-based nucleic acid structures and sixty-six protein-substrate complexes for halogen-oxygen interactions. Although not as frequent as halogen-oxygen interactions, halogen-nitrogen and halogen-sulfur contacts were identified as well. These scientific findings provide a unique basis for elucidating the role of halogen bonding in biological systems. On the bio-molecular level, halogen bonding is important for substrate specificity, binding and molecular folding. In the case of protein-ligand interactions, the most common charge-transfer bonds
Halogen bond
7128841
Hunsdiecker reaction The Hunsdiecker reaction (also called the Borodin reaction or the Hunsdiecker–Borodin reaction) is a name reaction in organic chemistry whereby silver salts of carboxylic acids react with a halogen to produce an organic halide. It is an example of both a decarboxylation and a halogenation reaction as the product has one fewer carbon atoms than the starting material (lost as carbon dioxide) and a halogen atom is introduced its place. The reaction was first demonstrated by Alexander Borodin in his 1861 reports of the preparation of methyl bromide from silver acetate. Shortly after, the approach was applied to
Hunsdiecker reaction
7128846
and lithium chloride (lithium bromide can also be used) to effect the halogenation and decarboxylation. Hunsdiecker reaction The Hunsdiecker reaction (also called the Borodin reaction or the Hunsdiecker–Borodin reaction) is a name reaction in organic chemistry whereby silver salts of carboxylic acids react with a halogen to produce an organic halide. It is an example of both a decarboxylation and a halogenation reaction as the product has one fewer carbon atoms than the starting material (lost as carbon dioxide) and a halogen atom is introduced its place. The reaction was first demonstrated by Alexander Borodin in his 1861 reports of
Hunsdiecker reaction
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organolithium species. Therefore, lithium halogen exchange is most frequently used to prepare vinyl-, aryl- and primary alkyllithium reagents. Lithium halogen exchange is also facilitated when alkoxy groups or heteroatoms are present to stabilize the carbanion, and this method is especially useful for the preparation of functionalized lithium reagents which cannot tolerate the harsher conditions required for reduction with lithium metal. Substrates such as vinyl halides usually undergo lithium-halogen exchange with retention of the stereochemistry of the double bond. Below is an example of the use of lithium-halogen exchange in the synthesis of morphine. Here, "n"-butyllithium is used to perform lithium-halogen
Organolithium reagent
631104
use. The compact size of the halogen lamp permits a reasonable size for portable projectors, although heat-absorbing filters must be placed between the lamp and the film to prevent melting. Halogen lamps are sometimes used for inspection lights and microscope stage illuminators. Halogen lamps were used for early flat-screen LCD backlighting, but other types of lamps are now used. Halogen lamps do not contain any mercury. General Electric claims that none of the materials making up their halogen lamps would cause the lamps to be classified as hazardous waste. Halogen lamp A halogen lamp, also known as a tungsten halogen,
Halogen lamp
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formal charge. As compared to hydrogen bonding, the halogen atom takes the place of the partially positively charged hydrogen as the electrophile. Halogen bonding should not be confused with halogen-aromatic interactions, as the two are related but differ by definition. Halogen-aromatic interactions involve an electron-rich aromatic π-cloud as a nucleophile; halogen bonding is restricted to monatomic nucleophiles. Van der Waals Forces are a subset of electrostatic interactions involving permanent or induced dipoles (or multipoles). These include the following: Hydrogen bonding and halogen bonding are typically not classified as Van der Waals forces. Dipole-dipole interactions are electrostatic interactions between permanent dipoles
Non-covalent interactions
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negative halogen ion occurs by the electron interaction with halogen molecules (dissociative attachment reaction): where "X" is a halogen atom. The second way is a harpooning reaction which is a binary process. In this case the excited rare gas species transfers its loosely bound electron to the halogen molecule or halogen-containing compound to form an electronically excited state of exciplex molecule "RgX*": Since the harpooning reaction is a two-body process it does not need so high pressure like for three-body reaction. So, the harpooning reaction makes available the excilamps operating at a low pressure of working mixture. As a result,
Excimer lamp
165508
halogen groups are far less reactive than aliphatic halogen groups, which can exhibit considerable chemical reactivity. For aliphatic carbon-halogen bonds, the C-F bond is the strongest and usually less chemically reactive than aliphatic C-H bonds. The other aliphatic-halogen bonds are weaker, their reactivity increasing down the periodic table. They are usually more chemically reactive than aliphatic C-H bonds. As a consequence, the most common halogen substitutions are the less reactive aromatic fluorine and chlorine groups. Fluoride anions are found in ivory, bones, teeth, blood, eggs, urine, and hair of organisms. Fluoride anions in very small amounts may be essential for
Halogen
19309039
and created its first Australian office in 2012. Between 2013 and 2015, it opened new offices in San Jose, North Carolina, Amsterdam and Dubai. In May 2013, Halogen Software debuted in the Toronto Stock Exchange under the ticker symbol HGN. The company stock jumped to 17 percent on its first day. In September 2013, Halogen Software launched two software modules to implement one-on-one sessions between managers and employees in the workforce and improve employee communication by incorporating the Myers–Briggs Type Indicator. In May 2017 Halogen Software was acquired by Saba Software for $293 million. Halogen Software Halogen Software is a
Halogen Software
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and covering Auckland, Wellington, Christchurch, and Dunedin. It also has operations in Singapore where it is considered an Institute of Public Character. National Young Leaders Day consists of a range of presenters, who aim to motivate young leaders in taking action in their schools and passing on the lessons they have learned on the day. Halogen Foundation is endorsed by national leaders of the respective countries. Mr John Howard (Prime Minister of Australia), Mrs Helen Clark (Prime Minister of New Zealand), and Mr Teo Chee Hean (Minister of Defense of Singapore). • Halogen Foundation (Singapore) • Halogen Foundation International Halogen
Halogen Foundation
13773984
Waite and Wallis were awarded APRA's Breakthrough Songwriter of the Year in 2002, an award they shared with Sia Furler. Follow-up singles "Superhero", "15 Minutes", and "Even Without You" reached #48, #72, and #97. Their debut album, "Words in Place of Objects", reached #87 on the ARIA albums chart. Aneiki Aneiki is a Brisbane pop duo made up of Jennifer Waite and Grant Wallis. The duo was originally called Halogen, but were forced to change their name after a Perth-based Halogen (band) established sole rights to the name's usage in Australia. Aneiki worked with songwriter Daniel Jones and were signed
Aneiki
13773983
Aneiki Aneiki is a Brisbane pop duo made up of Jennifer Waite and Grant Wallis. The duo was originally called Halogen, but were forced to change their name after a Perth-based Halogen (band) established sole rights to the name's usage in Australia. Aneiki worked with songwriter Daniel Jones and were signed to his label, Meridienmusik. Their debut single, "Pleased to Meet You", reached #26 on the ARIA singles chart, spending 18 weeks in the top 100 and was #13 on 2001's Australian Artist Singles chart. "Pleased To Meet You" was the most played Australian song on Australian radio in 2002.
Aneiki
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in a real fire scenario. However they do provide a measure by which the potential smoke emission of materials can be assessed and dangerous materials identified before proceeding to further testing of preferred materials, if deemed necessary. Low smoke zero halogen Low smoke zero halogen or low smoke free of halogen (LSZH or LSOH or LS0H or LSFH or OHLS) is a material classification typically used for cable jacketing in the wire and cable industry. LSZH cable jacketing is composed of thermoplastic or thermoset compounds that emit limited smoke and no halogen when exposed to high sources of heat. The
Low smoke zero halogen
7071787
Low smoke zero halogen Low smoke zero halogen or low smoke free of halogen (LSZH or LSOH or LS0H or LSFH or OHLS) is a material classification typically used for cable jacketing in the wire and cable industry. LSZH cable jacketing is composed of thermoplastic or thermoset compounds that emit limited smoke and no halogen when exposed to high sources of heat. The first commercial thermoplastic LSZH material for cable jacketing was invented by Richard Skipper in 1979 and patented by Raychem Corporation. This invention resolved the challenge of incorporating sufficient inorganic filler, aluminium trihydrate (ALTH), into an appropriate thermoplastic
Low smoke zero halogen
631092
construction, the halogen additive used and whether dimming is normally expected for this type. Like all incandescent light bulbs, a halogen lamp produces a continuous spectrum of light, from near ultraviolet to deep into the infrared. Since the lamp filament can operate at a higher temperature than a non-halogen lamp, the spectrum is shifted toward blue, producing light with a higher effective color temperature and higher power efficiency. This makes halogen lamps the only option for consumer light source with black-body radiation spectrum similar to that of the Sun and most suitable for the eyes. Alternatively, multi-component glasses can be
Halogen lamp
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which the halogen atom abstracts a hydrogen atom from a methane molecule, resulting in the formation of a hydrogen halide molecule and a methyl radical (CH•). The methyl radical then reacts with a molecule of the halogen to form a molecule of the halomethane, with a new halogen atom as byproduct. Similar reactions can occur on the halogenated product, leading to replacement of additional hydrogen atoms by halogen atoms with dihalomethane, trihalomethane, and ultimately, tetrahalomethane structures, depending upon reaction conditions and the halogen-to-methane ratio. Methane is used in industrial chemical processes and may be transported as a refrigerated liquid (liquefied
Methane
165507
color than other incandescent bulbs. However, this requires bulbs to be manufactured from fused quartz rather than silica glass to reduce breakage. In drug discovery, the incorporation of halogen atoms into a lead drug candidate results in analogues that are usually more lipophilic and less water-soluble. As a consequence, halogen atoms are used to improve penetration through lipid membranes and tissues. It follows that there is a tendency for some halogenated drugs to accumulate in adipose tissue. The chemical reactivity of halogen atoms depends on both their point of attachment to the lead and the nature of the halogen. Aromatic
Halogen
11202216
recent definition identifies crystal engineering as the utilization of the intermolecular interactions for crystallization and for the development of new substances with different desired physicochemical properties. Before the discovery of halogen bonding, the approach for crystal engineering involved using hydrogen bonding, coordination chemistry and inter-ion interactions for the development of liquid-crystalline and solid-crystalline materials. Furthermore, halogen bonding is employed for the organization of radical cationic salts, fabrication of molecular conductors, and creation of liquid crystal constructs. Since the discovery of halogen bonding, new molecular assemblies exist. Due to the unique chemical nature of halogen bonding, this intermolecular interaction serves as
Halogen bond
818467
method An alcohol on heating with halogen in presence of triphenyl phosphate produces haloalkanes or alkyl halides. Haloalkanes are reactive towards nucleophiles. They are polar molecules: the carbon to which the halogen is attached is slightly electropositive where the halogen is slightly electronegative. This results in an electron deficient (electrophilic) carbon which, inevitably, attracts nucleophiles. Substitution reactions involve the replacement of the halogen with another molecule—thus leaving saturated hydrocarbons, as well as the halogenated product. Haloalkanes behave as the R synthon, and readily react with nucleophiles. Hydrolysis, a reaction in which water breaks a bond, is a good example of
Haloalkane
7937703
Carius halogen method The Carius halogen method in analytical chemistry is a method for the quantitative determination of halogens in chemical substances. A known mass of an organic compound is heated with fuming nitric acid in the presence of silver nitrate contained in a hard glass tube known as carius tube, in a furnace. Carbon and hydrogen present in the compound are oxidised to carbon dioxide and water. The halogen present forms the corresponding silver halide (AgX). It is filtered, washed, dried and weighed. This chemical test works equally well for the determination of sulfur but without addition of silver
Carius halogen method
631090
The normal relationship regarding the lifetime is that it is proportional to formula_3. For example, a bulb operated at 5% higher than its design voltage would produce about 15% more light, and the luminous efficacy would be about 6.5% higher, but would be expected to have only half the rated life. Halogen lamps are manufactured with enough halogen to match the rate of tungsten evaporation at their design voltage. Increasing the applied voltage increases the rate of evaporation, so at some point there may be insufficient halogen and the lamp goes black. Over-voltage operation is not generally recommended. With a
Halogen lamp
12051909
Halogen Foundation Halogen Foundation (Singapore) is an Institute of Public Character and not-for-profit organization in Singapore whose mission is to inspire and influence a generation of young people to lead themselves and others well. Halogen Foundation was started in 1997 in Australia originally called the Young Leaders Foundation. Its hallmark program is the National Young Leaders Days, an annual event initiated in 1997 to develop student leadership in schools. The Foundation exists in five major cities in Australia - Sydney, Melbourne, Brisbane, Adelaide, and Perth. It can also be found in New Zealand, incorporated under the Charitable Trusts Act 1957]
Halogen Foundation
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nature of the XB donor. If the halogen is bonded to an electronegative (electron withdrawing) moiety, it is more likely to form stronger halogen bonds. For example, iodoperfluoroalkanes are well-designed for XB crystal engineering. In addition, this is also why F can act as a strong XB donor, but fluorocarbons are weak XB donors because the alkyl group connected to the fluorine is not electronegative. In addition, the Lewis base (XB acceptor) tends to be electronegative as well and anions are better XB acceptors than neutral molecules. Halogen bonds are strong, specific, and directional interactions that give rise to well-defined
Halogen bond
11202223
inclusion complexes appear to be mediated in part by unprecedented I-π interactions and by halogen bond between iodine and carbonyl groups. The crystal structure [shown below] come together in a triangular array and molecules of 2 are approximately symmetric. Additionally, all of the sets of halogen bonding interactions are not identical, and all of the intermolecular interactions between halogen and halogen bond acceptor slightly exceed the sum of the Van der Waals radius, signifying a slightly weaker halogen bond, which leads to more flexibility in the structure. The 2D layers stack parallel to each other to produce channels filled with
Halogen bond
631091
reduced voltage the evaporation is lower and there may be too much halogen, which can lead to abnormal failure. At much lower voltages, the bulb temperature may be too low to support the halogen cycle, but by this time the evaporation rate is too low for the bulb to blacken significantly. If the bulbs do blacken, it is recommended to run the lamps at the rated voltage to restart the cycle. There are many situations where halogen lamps are dimmed successfully. However, lamp life may not be extended as much as predicted. The life span on dimming depends on lamp
Halogen lamp
2786091
of lithiation is also determined by the directing effect of substituent groups. Some of the most effective directing substituent groups are alkoxy, amido, sulfoxide, sulfonyl. Metalation often occurs at the position ortho to these substituents. In heteroaromatic compounds, metalation usually occurs at the position ortho to the heteroatom. See lithium-halogen exchange (under Reactivity and applications) A third method to prepare organolithium reagents is through lithium halogen exchange. "tert-"butyllithium or "n-"butyllithium are the most commonly used reagents for generating new organolithium species through lithium halogen exchange. Lithium-halogen exchange is mostly used to convert aryl and alkenyl iodides and bromides with "sp2"
Organolithium reagent
631094
medical and dental instruments as a UV-B source. Halogen lamps get hotter than regular incandescent lamps because the heat is concentrated on a smaller envelope surface, and because the surface is closer to the filament. This high temperature is essential to their operation. Because the halogen lamp operates at very high temperatures, it can pose fire and burn hazards. In Australia, numerous house fires each year are attributed to ceiling-mounted halogen downlights. The Western Australia Department of Fire and Emergency Services recommends that home owners consider instead using compact fluorescent lamps or light emitting diode lamps because they produce less
Halogen lamp
631101
the Times Square Ball reaches the base used halogen lighting for the last time for the 2009 ball drop. It was announced on the Times Square website that the year numerals for the 2010 ball drop would use LEDs. Halogen lamps are the heating-elements in halogen ovens and ceramic cooktops. Banks of powerful tubular halogen lamps were used to simulate the heat of re-entry of space vehicles . Fixed-mount lamps are used in indoor and outdoor flood lighting, although improvements in LED systems are displacing halogen lamps. Round lamps with built-in multifaceted reflectors are widely used in residential and commercial
Halogen lamp
2479522
the tungsten accumulation. For these reasons, plain tungsten filaments are all but obsolete in automotive headlamp service. Tungsten-halogen technology (also called "quartz-halogen", "quartz-iodine", "iodine cycle", etc.) increases the effective luminous efficacy of a tungsten filament: when operating at a higher filament temperature which results in more lumens output per watt input, a tungsten-halogen lamp has a much longer brightness lifetime than similar filaments operating without the halogen regeneration cycle. At equal luminosity, the halogen-cycle bulbs also have longer lifetimes. European-designed halogen headlamp light sources are generally configured to provide more light at the same power consumption as their lower-output plain
Headlamp
862767
mixtures. The halogen tube discharge takes advantage of a metastable state of the inert gas atom to more-readily ionize a halogen molecule than an organic vapor, enabling the tube to operate at much lower voltages, typically 400–600 volts instead of 900–1200 volts. While halogen-quenched tubes have greater plateau voltage slopes compared to organic-quenched tubes (an undesirable quality), they have a vastly longer life than tubes quenched with organic compounds. This is because the organic vapor is gradually destroyed by the discharge process (giving organic-quenched tubes a useful life of around 10 events), while the halogen ions can recombine over time
Geiger–Müller tube
631100
J type and T type lamps. Halogen headlamps are used in many automobiles. Halogen floodlights for outdoor lighting systems as well as for watercraft are also manufactured for commercial and recreational use. They are now also used in desktop lamps. Tungsten-halogen lamps are frequently used as a near-infrared light source in Infrared spectroscopy. Halogen lamps were used on the Times Square Ball from 1999 to 2006. However, from 2007 onward, the halogen lamps were replaced with LEDs, due to the much longer potential lifespan (about ten times longer for LED over incandescent). The 'New Year' numerals that light up when
Halogen lamp
359814
the combustion, polymers containing halogen only (e.g. polytetrafluoroethylene) have lower CI as the formation of acid is limited to reactions with airborne humidity, and halogen-free materials (polyolefins, wood) have the lowest CI. However, some halogen-free materials can also release significant amount of corrosive products. Smoke damage to electronic equipment can be significantly more extensive than the fire itself. Cable fires are of special concern; low smoke zero halogen materials are preferable for cable insulation. When smoke comes into contact with the surface of any substance or structure, the chemicals contained in it are transferred to it. The corrosive properties of
Smoke
4079905
octatomic interhalogens involve a heavier halogen combined with five or seven fluorine atoms. Unlike the other halogens, fluorine atoms have high electronegativity and small size which is able to stabilize them. Typically, interhalogen bonds are more reactive than diatomic halogen bonds—because interhalogen bonds are weaker than diatomic halogen bonds, except for F. If interhalogens are exposed to water, they convert to halide and oxyhalide ions. With BrF, this reaction can be explosive. If interhalogens are exposed to silicon dioxide, or metal oxides, then silicon or metal respectively bond with one of the types of halogen, leaving free diatomic halogens and
Interhalogen
11202218
measured in solid powders. The N−I distance discovered is shorter than the sum of the Van Der Waals radii for nitrogen and iodine (3.53 Å). The single crystal structure of the molecules indicated that no quadrupolar interactions were present. The complexes in Figure 4 were found to be liquid-crystalline. To test the notion of polarizability involvement in the strength of halogen bonding, bromopentafluorbenzene was used as a Lewis base. Consequently, verification of halogen bond complex formation wasn’t obtained. This finding provides more support for the dependence of halogen bonding on atomic polarizability. Utilizing similar donor-acceptor frameworks, the authors demonstrated that
Halogen bond
11202226
with polarizable halogens involve backbone carbonyls and/or hydroxyl and carboxylate groups of amino acid residues. Typically in DNA and protein-ligand complexes, the bond distance between Lewis base donor atoms (e.g. O, S, N) and Lewis acid (halogen) is shorter than the sum of their Van der Waals radius. Depending on the structural and chemical environment, halogen bonding interactions can be weak or strong. In the case of some protein-ligand complexes, halogen bonds are energetically and geometrically comparable to that of hydrogen bonding if the donor-acceptor directionality remains consistent. This intermolecular interaction has been shown to be stabilizing and a conformational
Halogen bond
6988589
the keeper's room. As the rotation was electrically driven by motors, the crew was reduced to four men. In 1988 the 4th Order optic was replaced by a rotating beacon. This comprised an array of quartz halogen lamps in aluminium parabolic reflectors mounted on a gearless revolving pedestal. The lamps require only one-fifth of the energy required to produce the same intensity as incandescent lamps. These low-power lamps therefore allow solar power to be used in place of generators. In addition, the operation of the light is controlled by a photocell. The manning of the lighthouse was further reduced to
Raffles Lighthouse
631085
the halogen, however, sets up a reversible chemical reaction cycle with this evaporated tungsten. The halogen cycle keeps the bulb clean and causes the light output to remain almost constant throughout the bulb's life. At moderate temperatures the halogen reacts with the evaporating tungsten, the halide formed being moved around in the inert gas filling. At some point, however, it will reach higher temperature regions within the bulb where it then dissociates, releasing tungsten back onto the filament and freeing the halogen to repeat the process. However, the overall bulb envelope temperature must be significantly higher than in conventional incandescent
Halogen lamp
2479523
tungsten counterparts. By contrast, many US-based designs are configured to reduce or minimize the power consumption while keeping light output above the legal minimum requirements; some US tungsten-halogen headlamp light sources produce less initial light than their non-halogen counterparts. A slight theoretical fuel economy benefit and reduced vehicle construction cost through lower wire and switch ratings were the claimed benefits when American industry first chose how to implement tungsten-halogen technology. There was an improvement in seeing distance with US halogen high beams, which were permitted for the first time to produce 150,000 candela (cd) per vehicle, double the non-halogen limit
Headlamp
818464
must be absent otherwise there will be a side product of a halohydrin. The reaction is necessarily to be carried out in a dry inert solvent such as or directly in the gaseous phase. The reaction of alkynes are similar, with the product being a geminal dihalide; once again, Markovnikov's rule is followed. Alkenes also react with halogens (X) to form haloalkanes with two neighboring halogen atoms in a halogen addition reaction. Alkynes react similarly, forming the tetrahalo compounds. This is sometimes known as "decolorizing" the halogen, since the reagent X is colored and the product is usually colorless and
Haloalkane
17245772
pressure of P is low enough either filler gas is admitted to the bulb prior to sealing off or, if a vacuum atmosphere is desired the bulb is sealed off at that point. The high decomposition temperature of PN allows sealing machines to run faster and hotter than was possible using red phosphorus. Related halogen containing polymers, trimeric bromophosphonitrile, (PNBr), m.p. 192 °C and tetrameric bromophosphonitrile, (PNBr), m.p. 202 °C find similar lamp gettering applications for tungsten halogen lamps, where they perform the dual processies of gettering and precise halogen dosing. It has also been investigated as a new material
Triphosphorus pentanitride
631088
the filament is also possible with fluorine, but its chemical reactivity is so great that other parts of the lamp are attacked. The halogen is normally mixed with a noble gas, often krypton or xenon. The first lamps used only tungsten for filament supports, but some designs use molybdenum – an example being the molybdenum shield in the H4 twin filament headlight for the European Asymmetric Passing Beam. For a fixed power and life, the luminous efficacy of all incandescent lamps is greatest at a particular design voltage. Halogen lamps made for 12 to 24 volt operation have good light
Halogen lamp
7882824
A circuit and breaker. The English name is PH Artichoke ("artichoke"). The original Danish name is "PH Kogle" ("conifer cone") This name is also used in Norway and Germany /"PH Kogle/PH Zapfen". PH Artichoke The PH Artichoke Pendant is a Light fixture designed by Danish architect and designer Poul Henningsen and manufactured by Louis Poulsen. It was created for the Langelinie Pavilion in Copenhagen in 1958. A chrome inner diffuser also assists in the proper even reflection of the light source. The light source can be an incandescent bulb (high powered halogen or xenon), fluorescent (with the ballast mounted in
PH Artichoke
5469135
nickel(II) chloride with fluorine at 350 °C: 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 is less stable. Chloride is more easily oxidized than nickel(II). This is a typical halogen displacement reaction, where a halogen plus a less active halide makes the less active halogen and the more active halide. Nickel(II) fluoride is also produced when fluorine reacts with nickel metal. A melt of NiF and KF reacts to give the green compound K[NiF]. The structure of this material is closely
Nickel(II) fluoride
2773210
which commonly refers to NO. If the cationic center of the hydride is not a halogen, chalcogen or pnictogen then the suffix "-ium" is added to the name of the neutral hydride after dropping any final 'e'. HC is methanium, HO-(O)-H is dioxidanium (HO-OH is dioxidane), and HN-(N)-H is diazanium (HN-NH is diazane). The above cations except for methanium are not, strictly speaking, organic, since they do not contain carbon. However, many organic cations are obtained by substituting another element or some functional group for a hydrogen. The name of each substitution is prefixed to the hydride cation name. If
IUPAC nomenclature of organic chemistry
11202215
of the halogen bond is the result of an anisotropic distribution of electron density around the halogen nucleus and paved the way to the definition of the “σ-hole”. Currently, XB is being exploited for a range of functional applications, e.g., crystal engineering, supramolecular chemistry, polymer sciences, liquid crystals, conductive materials and medicinal chemistry. Crystal engineering is a growing research area that bridges solid-state and supramolecular chemistry. This unique field is interdisciplinary and merges traditional disciplines such as crystallography, organic chemistry, and inorganic chemistry. In 1971, Schmidt first established the field with a publication on photodimerization in the solid-state. The more
Halogen bond
631086
lamps for this reaction to succeed: it is only at temperatures of above on the inside of the glass envelope that the halogen vapor can combine with the tungsten and return it to the filament rather than the tungsten becoming deposited on the glass. A 300 watt tubular halogen bulb operated at full power quickly reaches a temperature of about , while a 500 watt regular incandescent bulb operates at only and a 75 watt regular incandescent at only . The bulb must be made of fused silica (quartz) or a high-melting-point glass (such as aluminosilicate glass). Since quartz is
Halogen lamp
11202222
and molecular separation devices. Molecular organization is often controlled via intermolecular forces such as hydrogen bonding. However, utilizing hydrogen bonding often limits the range of pore sizes available due to close packing. Pigge, et al., utilized halogen bonding interactions between amines, nitrogen heterocycles, carbonyl groups, and other organic halides, to construct their porous structures. This is significant because organic crystalline networks mediated by halogen bonds, an interaction significantly weaker than hydrogen bond, are rare. Crystal structures of 1 and 2 [below] were obtained in a variety of solvents, such as dichloromethane, pyridine, and benzene. The authors note that the porous
Halogen bond
4814065
either acidic or basic conditions, to give bromoacetone: Acidic (in acetic acid): Basic (in aqueous NaOH): In acidic solution, usually only one alpha hydrogen is replaced by a halogen, because each successive halogenation is slower than the first. The halogen decreases the basicity of the carbonyl oxygen, thus making protonation less favorable. However, in basic solution successive halogenations are more rapid due to inductive electron withdrawal by the halogen, making the remaining hydrogens more acidic. In the case of methyl ketones, this reaction often occurs a third time to form a ketone trihalide, which can undergo rapid substitution with water
Ketone halogenation
11202219
halogen bonding strength in the liquid crystalline state is comparable to the hydrogen-bonded mesogens. Applications utilizing properties of conjugated polymers emerged from work done by Heeger, McDiaramid, and Shirakawa with the discovery that polyacetylene is a conducting, albeit difficult to process material. Since then, work has been done to mimic this conjugated polymer’s backbone (e.g., poly(p-phenylenevinylene)). Conjugated polymers have many practical applications, and are used in devices such as photovoltaic cells, organic light-emitting diodes, field-effect transistors, and chemical sensors. Goroff et al. prepared ordered poly(diiododiacetylene) (PIDA) via prearrangement of monomer (2) with a halogen bond scaffolding. PIDA is an excellent
Halogen bond
1801030
is a halogen atom bearing a negative charge. The halide anions are fluoride (F), chloride (Cl), bromide (Br), iodide (I) and astatide (At). Such ions are present in all ionic halide salts. Halide minerals contain halides. All these halides are colourless, high melting crystalline solids having high negative enthalpies of formation. Halide compounds such as KCl, KBr and KI can be tested with silver nitrate solution, AgNO. The halogen will react with Ag and form a precipitate, with varying colour depending on the halogen: For organic compounds containing halides, the Beilstein test is used. are used in high-intensity discharge lamps
Halide
5054906
IUPAC nomenclature for organic transformations The IUPAC Nomenclature for Transformations is a methodology for naming a chemical reaction. Traditionally a chemical reaction especially in organic chemistry is named after its inventor, the so-called named reaction, to name just a few: Knoevenagel condensation, Wittig reaction or Diels-Alder reaction. A lot of reactions derive their name from the reagent involved like bromination or acylation. On rare occasions the reaction is named after the company responsible like in the Wacker process or the name only hints to the process involved like in the halogen dance rearrangement. The related IUPAC nomenclature is designed for
IUPAC nomenclature for organic transformations
12516978
you seek the name of their nature, it is 'spirit'; if you seek the name of their office, it is 'angel': from what they are, 'spirit', from what they do, 'angel'." Basilian Father Thomas Rosica says, "Angels are very important, because they provide people with an articulation of the conviction that God is intimately involved in human life." By the late 4th century, the Church Fathers agreed that there were different categories of angels, with appropriate missions and activities assigned to them. There was, however, some disagreement regarding the nature of angels. Some argued that angels had physical bodies, while
Angel
7937704
nitrate. The sulfuric acid intermediate formed after reaction of sulfur with fuming nitric acid forms insoluble barium sulfate on addition of barium chloride. This test was invented by the German Chemist, Georg Ludwig Carius (1829–1875). Carius halogen method The Carius halogen method in analytical chemistry is a method for the quantitative determination of halogens in chemical substances. A known mass of an organic compound is heated with fuming nitric acid in the presence of silver nitrate contained in a hard glass tube known as carius tube, in a furnace. Carbon and hydrogen present in the compound are oxidised to carbon
Carius halogen method
20359698
Chalcogen bond A chalcogen bond is an attractive interaction in the family of σ-hole interactions, along with hydrogen bonds and halogen bonds. This family of attractive interactions has been modeled as an electron donor interacting with the σ* orbital of a C-X bond (X= hydrogen, halogen, chalcogen, pnictogen, etc.). Electron density mapping is often invoked to visualize the electron density of the donor and an electrophilic region on the acceptor, referred to as a σ-hole. Chalcogen bonds, much like hydrogen and halogen bonds, have been invoked in various non-covalent interactions, such as protein folding, crystal engineering, self-assembly, catalysis, transport, sensing,
Chalcogen bond
17355270
but XeCl*, KrCl*, XeBr*, ArCl*, XeCl* are exciplex molecules. The best known include rare gas excimers and rare-gas-halogen excimers. Rare-gas-halogen trimers, metal excimers, metal-rare-gas excimers, metal-halogen excimers and rare-gas-oxygen excimers are also known. Because of these excimer formations are unstable they disintegrate within a few nanoseconds converting their excitation energy to optical radiation. Because of the excimer molecule nature the difference between their stable excited state and weakly bound ground state amounts from 3.5 to 10 eV that is provided radiation of UV and VUV spectral range. The spectrum of excimer lamp radiation is characterized by an intense narrow emission
Excimer lamp
5832520
of thousands complexes in chloroform or carbontetrachloride have led to additive free energy increments for all kind of donor-acceptor combinations. Halogen bonding is a type of non-covalent interaction which does not involve the formation nor breaking of actual bonds, but rather is similar to the dipole-dipole interaction known as hydrogen bonding. In halogen bonding, a halogen atom acts as an electrophile, or electron-seeking species, and forms a weak electrostatic interaction with a nucleophile, or electron-rich species. The nucleophilic agent in these interactions tends to be highly electronegative (such as oxygen, nitrogen, or sulfur), or may be anionic, bearing a negative
Non-covalent interactions
3882436
a bicycle headlamp properly shaped to illuminate the roadway and not provide excess glare to oncoming traffic. Although these lights were originally designed for off-road use, where they are almost universal, rechargeable halogen lights became popular with commuter cyclists. The lights used by most halogen rechargeable systems are cheap, bright but fairly simple: they project a cone of light (wide and narrow beam options are available) which is good for off-road use but not ideal for road use as it can dazzle oncoming road users. This is why rechargeable halogen lights do not meet legal requirements in some jurisdictions. Many
Bicycle lighting
631084
patent, which also described the cyclic redeposition of tungsten back onto the filament. In 1959, General Electric patented a practical lamp using iodine. In 2009, the EU began its phase-out of inefficient bulbs. The production and importation of directional mains-voltage halogen bulbs was banned on 1 September 2016 and non-directional halogen bulbs followed on 1 September 2018. Australia will ban halogen light bulbs from September 2020. In ordinary incandescent lamps, evaporated tungsten mostly deposits onto the inner surface of the bulb, causing the bulb to blacken and the filament to grow increasingly weak until it eventually breaks. The presence of
Halogen lamp
11202213
typical characteristics found in halogen bond formation and led Hassel to conclude that halogen atoms are directly linked to electron pair donor with a bond direction that coincides with the axes of the orbitals of the lone pairs in the electron pair donor molecule. In 1969, Hassel was awarded the Nobel Prize in Chemistry for his outstanding discovery that halogens can act as electrophilic, electron acceptors, and self-assemble into highly, directionally organised crystalline charge-transfer complexes in presence of electron donors. An early review about electron donor-acceptor was provided by Bent in 1968. The use of the term "halogen bond" was
Halogen bond
3024705
Halogen (band) Halogen was a five-piece band from Perth, Western Australia. Formed in 1998 by two expatriate New Zealanders - Jasmine Yee and Frans Bisschops. After self-releasing a debut EP titled "Into the Crash Barrier" in 1999, Halogen then gained national prominence in Australia through the song "Hole Around My Heart" from their 2001 Phantom/MGM-released EP "Somewhere You're Alone". The song won the WAM Song of the Year in 2001. With the release of the single "Walkaway", and an accompanying tour of Australia's east coast (including a showcase performance at the Australian Music Week), the band furthered their claim for
Halogen (band)
11202214
not implemented until 1978 by Dumas and coworkers, who investigated complexes of CCl, CBr, SiCl, and SiBr with tetrahydrofuran, tetrahydropyran, pyridine, anisole, and di-n-butyl ether in organic solvents. However, it was not until the mid-1990s, that the nature and applications of the halogen bond began to be intensively studied. Systematic and extensive work by Legon and coworkers, who studied a wide variety of halogen-bonded adducts formed in the gas phase via microwave spectroscopy, drew attention to the similarities between halogen-bonding and better-known hydrogen-bonding interactions. Computational calculations by Politzer and Murray were particularly significant as they revealed that the high directionality
Halogen bond
3024708
well as vocals for "Can’t let You be Lonely" by The Transients. After several lineup changes, Yee and Bisschops formed on an electronica-based side project with local producer, Trilby Temperley, the older brother of Kavyen Temperley (Eskimo Joe), called She Selexx. Halogen (band) Halogen was a five-piece band from Perth, Western Australia. Formed in 1998 by two expatriate New Zealanders - Jasmine Yee and Frans Bisschops. After self-releasing a debut EP titled "Into the Crash Barrier" in 1999, Halogen then gained national prominence in Australia through the song "Hole Around My Heart" from their 2001 Phantom/MGM-released EP "Somewhere You're Alone".
Halogen (band)
16597038
follow from binary collisions. These reactions involve the chlorine donor at the ground state and an excited atom of xenon, both in the first 6s, Xe and at higher levels Xe such as level 6p. Generally, these reactions can describe the result of collisions of the noble gas atoms (Rg) and halogen donors (RX), where X is a halogen atom and R a radical molecule. The products of the reactions depend strongly on the type of rare gas and halogen donor. In our case where Rg = Xe and X = Cl, the nature of the products follows this rule.
Xenon monochloride
4079907
atom of the compound. Interhalogens containing fluorine are more likely to be volatile than interhalogens containing heavier halogens. Interhalogens with one or three halogens bonded to a central atom are formed by two elements whose electronegativities are not far apart. Interhalogens with five or seven halogens bonded to a central atom are formed by two elements whose sizes are very different. The number of smaller halogens that can bond to a large central halogen is guided by the ratio of the atomic radius of the larger halogen over the atomic radius of the smaller halogen. A number of interhalogens, such
Interhalogen
11202228
the functional activity of aldehyde reductase is impaired. Carboxylate and aldehyde inhibitors were shown to hydrogen bond with Trp 111, Tyr 48, and His 110. The “specificity pocket,” created as a result of inhibitor binding, consists of Leu 300, Ala 299, Phe 122, Thr 113, and Trp 111. For inhibitors to be effective, the key residues of interaction were identified to be Thr 113 and Trp 111. IDD 594 was designed such that the halogen would provide selectivity and be potent. Upon binding, this compound induces a conformational change that causes halogen bonding to occur between the oxygen of the
Halogen bond
2908213
kind of nonmetal element is a halogen (e.g., fluorine (F) or chlorine (Cl)). Such an atom has the following electron configuration: sp; this requires only one additional valence electron to form a closed shell. To form an ionic bond, a halogen atom can remove an electron from another atom in order to form an anion (e.g., F, Cl, etc.). To form a covalent bond, one electron from the halogen and one electron from another atom form a shared pair (e.g., in the molecule H–F, the line represents a shared pair of valence electrons, one from H and one from F).
Valence electron
3882438
they have the same advantages and disadvantages as rechargeable halogen systems, and like halogen systems they are designed primarily for off-road use, having rotationally symmetrical beams which cast as much light up as down. An additional disadvantage compared with halogen or LED lights is that the HID lamp does not tolerate repeated strikes, and in many cases does not relight immediately after shutting down. Likewise, should the battery level fall too low, the lamp will shut down rather than dimming. But the longer battery life than halogens tends to negate these problems, as many riders simply switch the light on
Bicycle lighting
6244169
of the loss of chain end functionality based on H NMR and mass spectroscopy methods cannot provide precise values. As a result, it is difficult to identify the contributions of different chain breaking reactions in ATRP. One simple rule in ATRP comprises the principle of halogen conservation. Halogen conservation means the total amount of halogen in the reaction systems must remain as a constant. From this rule, the level of retention of chain end functionality can be precisely determined in many cases. The precise determination of the loss of chain end functionality enabled further investigation of the chain breaking reactions
Atom transfer radical polymerization
7071789
happens at approximately the same temperature. The steam disrupts combustion of the evolved gases and helps form a char layer that protects the remaining material and traps particulates. The high level of filler required (≈ 60%) also replaces the base polymer reducing the total amount of fuel available for combustion. Low smoke zero halogen cable considerably reduces the amount of toxic and corrosive gas emitted during combustion. When burned, a low-smoke zero halogen cable emits a less optically dense smoke that releases at a lower rate. During a fire, a low-smoke cable is desirable because it reduces the amount and
Low smoke zero halogen
14397921
starting to evolve. This was a projection-style DJ light that used a halogen lamp and a mirror to reflect the light. A halogen lamp shines onto a mirror via a filter gel sheet to create the color and sometimes via a gobo wheel to create shapes. In some DJ lighting effects a coloured mirror is used to avoid using color/filter gel. Most modern projector DJ lights now use LEDs instead of halogen lamps. Lasers are a relatively new type of DJ light. They use a laser diode and an array of mirrors to project multiple colours and beams of light.
DJ lighting
20359701
the electrophilic gate, the donor region which is electron enriched. Any electron donor can donate electrons into the σ-hole of a bonded chalcogen, including halogen anions, amines, and π electrons (such as benzene). Similar to halogen bonding, chalcogen bonding can occur between two chalcogens, resulting in a chalcogen-chalcogen bond. Non-covalent interactions are well characterized by Bader's atoms in molecules (AIM) model which defines a bond as any bond-critical point (BCP) existing between two nuclei. This can be understood simply as a saddle point on an electron density map of a molecule. Hydrogen and halogen bonds are both well characterized by
Chalcogen bond
5006841
Halohydrin In organic chemistry a halohydrin (also a haloalcohol or β-halo alcohol) is a functional group in which a halogen and a hydroxyl are bonded to adjacent carbon atoms, which otherwise bear only hydrogen or hydrocarbyl groups (e.g. 2-chloroethanol, 3-chloropropane-1,2-diol). The term only applies to saturated motifs, as such compounds like 2-chlorophenol would not normally be considered halohydrins. Megatons of some chlorohydrins, e.g. propylene chlorohydrin, are produced annually as precursors to polymers. Halohydrins may be categorized as chlorohydrins, bromohydrins, fluorohydrins or iodohydrins depending on the halogen present. Halohydrins are usually prepared by treatment of an alkene with a halogen, in
Halohydrin
15469694
Autoclave, Blackout, Onslaught, Trypticon, The Combaticons/Bruticus Maximus (Onslaught is the only Combaticon that is referred to by name in the book), The Constructicons/Devastator (None of the individual Constructicons are referred to by name). Three unnamed Insecticons, Armorhide, Fastback, Bumper, the Lightning Strike Coalition Force (Grimlock, Swoop,) Chromatron, Hydrau, the Cybertron High Council (Halogen, Gauntlet, Drivetrain and Sigil. Ratbat and Contrail are two High Council members who join the Decepticons when the war begins). It is implied that "Transformers: Exodus", along with its two sequels, "" and "" are placed within the same continuity of the animated TV show "" and
Transformers: Exodus
15640152
Dehalobacter Dehalobacter is a genus in the phylum Firmicutes (Bacteria). The generic name "Dehalobacter" derives from Latin "de", from; "halogenum" from Swedish, coined by Swedish chemist Baron Jöns Jakob Berzelius (1779–1848) from Greek "hals", "halos" "salt" + "gen" "to produce", so called because a salt is formed in reactions involving these elements; a rod "bacter", nominally meaning "a rod", but in effect meaning a bacterium, a rod; giving "Dehalobacter", a halogen-removing, rod-shaped bacterium. The genus contains a single species, namely "D. restrictus" ( Holliger "et al". 1998, type species of the genus. The specific name is from Latin "restrictus", limited,
Dehalobacter
2027678
South Shetland Islands, Antarctica is named after Dobrich. A point of interest is the Dobrich TV Tower. The city is named after the 14th-century Dobrujan ruler Dobrotitsa, from the Slavic root "dobr", "good" The first evidence of settlement in what is now Dobrich dates from the 4th or 3rd century BC. Under the Latin name Abrittum, it was a city of the Roman province of Moesia Inferior, important enough to become a suffragan bishopric of the Metropolitan of the capital, Marcianopolis, but the Catholic diocese faded later. Ruins from 2nd to 4th centuries AD and the 7th to 11th centuries
Dobrich
10050748
had tried to rape her. The late 4th century AD Latin poet Claudian in his "Gigantomachia", has Pallas, as one of several Giants turned to stone by Minerva's Gorgon shield, calling out "What is happening to me? What is this ice that creeps o're all my limbs? What is this numbness that holds me prisoner in these marble fetters?" Pallas was also the name of a Titan, with whom the Giant is sometimes confused or identified. Pallas (Giant) In Greek mythology, Pallas (/ˈpæləs/; Ancient Greek: Πάλλας) was one of the Gigantes (Giants), the offspring of Gaia, born from the blood
Pallas (Giant)
12334125
49.0 x 56.0 mm Compression ratio: 9.0:1 Starting system: Kick start/Self starter (from 2008 models) Lubrication: Compulsive pressure wet sump Carburettor: Variable venturi type Ignition system: Capacitor discharge ignition (advanced micro processor), Magneto dependent Battery type: 12 V, 2.5 A·h Clutch type: Wet multiple-disc Transmission type: Four steps of regular engagement formula advance. 1 down, 3 up; toe-heel shifter Gear ratios: 1st=3.000, 2nd＝1.688, 3rd:=1.200, 4th=0.875 Primary / Secondary reduction ratio 3.722 / 3.214 Frame type: Double cradle type Caster angle (degree): 26.4° Suspension type: (front/rear) Telescopic/swing arm Headlight: 12 V 35/35 W halogen bulb (HS1) Top speed: +/-87 km/h (54
Yamaha Libero (G5)