"iodine is still one of the more reactive elements. For example, while chlorine gas will halogenate carbon monoxide, nitric oxide, and sulfur dioxide (to phosgene, nitrosyl chloride, and sulfuryl chloride respectively), iodine will not do so. Furthermore, iodination of metals tends to result in lower oxidation states than chlorination or bromination; for example, rhenium metal reacts with chlorine to form rhenium hexachloride, but with bromine it forms only rhenium pentabromide and iodine can achieve only rhenium tetraiodide. By the same token, however, since iodine has the lowest ionisation energy among the halogens and is the most easily oxidised of them,"
"weaker reducing agent than iodide, but a stronger one than chloride. These similarities led to chlorine, bromine, and iodine together being classified as one of the original triads of Johann Wolfgang Döbereiner, whose work foreshadowed the periodic law for chemical elements. It is intermediate in atomic radius between chlorine and iodine, and this leads to many of its atomic properties being similarly intermediate in value between chlorine and iodine, such as first ionisation energy, electron affinity, enthalpy of dissociation of the X molecule (X = Cl, Br, I), ionic radius, and X–X bond length. The volatility of bromine accentuates its"
"Dissolved chlorine reacts to form hydrochloric acid (HCl) and hypochlorous acid, a solution that can be used as a disinfectant or bleach: Bromine has a solubility of 3.41 g per 100 g of water, but it slowly reacts to form hydrogen bromide (HBr) and hypobromous acid (HBrO): Iodine, however, is minimally soluble in water (0.03 g/100 g water at 20 °C) and does not react with it. However, iodine will form an aqueous solution in the presence of iodide ion, such as by addition of potassium iodide (KI), because the triiodide ion is formed. The table below is a summary"
"spallation of argon-36. A total of 24 isotopes of chlorine have been discovered, with atomic masses ranging from 28 to 51. There are two stable and naturally occurring isotopes of bromine, bromine-79 and bromine-81. A total of 32 isotopes of bromine have been discovered, with atomic masses ranging 67 to 98. There is one stable and naturally occurring isotope of iodine, iodine-127. However, there are trace amounts in nature of the radioactive isotope iodine-129, which occurs via spallation and from the radioactive decay of uranium in ores. Several other radioactive isotopes of iodine have also been created naturally via the"
"of krypton; and Br may decay by either mode to stable Se or Kr. Bromine is intermediate in reactivity between chlorine and iodine, and is one of the most reactive elements. Bond energies to bromine tend to be lower than those to chlorine but higher than those to iodine, and bromine is a weaker oxidising agent than chlorine but a stronger one than iodine. This can be seen from the standard electrode potentials of the X/X couples (F, +2.866 V; Cl, +1.395 V; Br, +1.087 V; I, +0.615 V; At, approximately +0.3 V). Bromination often leads to higher oxidation states"
"the I–Cl bond occurs and I attacks phenol as an electrophile. However, iodine monobromide tends to brominate phenol even in tetrachloromethane solution because it tends to dissociate into its elements in solution, and bromine is more reactive than iodine. When liquid, iodine monochloride and iodine monobromide dissociate into and anions (X = Cl, Br); thus they are significant conductors of electricity and can be used as ionising solvents. Iodine trifluoride (IF) is an unstable yellow solid that decomposes above −28 °C. It is thus little-known. It is difficult to produce because fluorine gas would tend to oxidise iodine all the"
"crushed. Chlorine is an insulator in all of its forms. It has a high ionisation energy (1251.2 kJ/mol), high electron affinity (349 kJ/mol; higher than fluorine), and high electronegativity (3.16). Chlorine is a strong oxidising agent (Cl + 2""e"" → 2HCl = 1.36 V at pH 0). Metal chlorides are largely ionic in nature. The common oxide of chlorine (ClO) is strongly acidic. Bromine is a deep brown diatomic liquid that is quite reactive, and has a liquid density of 3.1028 g/cm. It boils at 58.8 °C and solidifies at −7.3 °C to an orange crystalline solid (density 4.05 g/cm)."
"dioxide with nitrate ores, which contain some iodates. Iodine is also extracted from natural gas fields. Even though astatine is naturally occurring, it is usually produced by bombarding bismuth with alpha particles. Both chlorine and bromine are used as disinfectants for drinking water, swimming pools, fresh wounds, spas, dishes, and surfaces. They kill bacteria and other potentially harmful microorganisms through a process known as sterilization. Their reactivity is also put to use in bleaching. Sodium hypochlorite, which is produced from chlorine, is the active ingredient of most fabric bleaches, and chlorine-derived bleaches are used in the production of some paper"
"Iron reacts with fluorine, chlorine, and bromine to form Iron(III) halides. These reactions are in the form of: However, when iron reacts with iodine, it forms only iron(II) iodide. Iron wool can react rapidly with fluorine to form the white compound iron(III) fluoride even in cold temperatures. When chlorine comes into contact with heated iron, they react to form the black iron (III) chloride. However, if the reaction conditions are moist, this reaction will instead result in a reddish-brown product. Iron can also react with bromine to form iron(III) bromide. This compound is reddish-brown in dry conditions. Iron's reaction with"
"vigorous fluorinating agent, although chlorine trifluoride is still more violent. Bromine pentafluoride explodes on reaction with water and fluorinates silicates at 450 °C. Although dibromine is a strong oxidising agent with a high first ionisation energy, very strong oxidisers such as peroxydisulfuryl fluoride (SOF) can oxidise it to form the cherry-red cation. A few other bromine cations are known, namely the brown and dark brown . The tribromide anion, , has also been characterised; it is analogous to triiodide. Bromine oxides are not as well-characterised as chlorine oxides or iodine oxides, as they are all fairly unstable: it was once"
"monochloride. Iodine monochloride and iodine monobromide may be prepared simply by reacting iodine with chlorine or bromine at room temperature and purified by fractional crystallisation. Both are quite reactive and attack even platinum and gold, though not boron, carbon, cadmium, lead, zirconium, niobium, molybdenum, and tungsten. Their reaction with organic compounds depends on conditions. Iodine chloride vapour tends to chlorinate phenol and salicyclic acid, since when iodine chloride undergoes homolytic dissociation, chlorine and iodine are produced and the former is more reactive. However, iodine chloride in tetrachloromethane solution results in iodination being the main reaction, since now heterolytic fission of"
"than bromine or iodine. This can be seen from the standard electrode potentials of the X/X couples (F, +2.866 V; Cl, +1.395 V; Br, +1.087 V; I, +0.615 V; At, approximately +0.3 V). However, this trend is not shown in the bond energies because fluorine is singular due to its small size, low polarisability, and lack of low-lying d-orbitals available for bonding (which chlorine has). As another difference, chlorine has a significant chemistry in positive oxidation states while fluorine does not. Chlorination often leads to higher oxidation states than bromination or iodination but lower oxidation states to fluorination. Chlorine tends"
"chlorine, comprising only 2.5 parts per million of the Earth's crustal rocks, and then only as bromide salts. It is the forty-sixth most abundant element in Earth's crust. It is significantly more abundant in the oceans, resulting from long-term leaching. There, it makes up 65 parts per million, corresponding to a ratio of about one bromine atom for every 660 chlorine atoms. Salt lakes and brine wells may have higher bromine concentrations: for example, the Dead Sea contains 0.4% bromide ions. It is from these sources that bromine extraction is mostly economically feasible. The main sources of bromine are in"
"surface of the , open Ivanhoe Reservoir with black, plastic shade balls to block the sunlight which causes the naturally present bromide to react with the chlorine used in treatment. 30 million of the 40 cent balls ($12 million) are required to cover the Ivanhoe and Elysian reservoirs. Currently no bromate-bearing minerals (i.e., the ones with bromate ion being an essential constituent) are known. Bromate The bromate anion, BrO, is a bromine-based oxoanion. A bromate is a chemical compound that contains this ion. Examples of bromates include sodium bromate, (), and potassium bromate, (). Bromates are formed many different ways"
"element, but the French Academy changed the element's name to bromine. Iodine was discovered by Bernard Courtois, who was using seaweed ash as part of a process for saltpeter manufacture. Courtois typically boiled the seaweed ash with water to generate potassium chloride. However, in 1811, Courtois added sulfuric acid to his process, and found that his process produced purple fumes that condensed into black crystals. Suspecting that these crystals were a new element, Courtois sent samples to other chemists for investigation. Iodine was proven to be a new element by Joseph Gay-Lussac. In 1931, Fred Allison claimed to have discovered"
"""chemical magic"". Chlorine azide (ClN) and bromine azide (BrN) are extremely sensitive and explosive. Two series of nitrogen oxohalides are known: the nitrosyl halides (XNO) and the nitryl halides (XNO). The first are very reactive gases that can be made by directly halogenating nitrous oxide. Nitrosyl fluoride (NOF) is colourless and a vigorous fluorinating agent. Nitrosyl chloride (NOCl) behaves in much the same way and has often been used as an ionising solvent. Nitrosyl bromide (NOBr) is red. The reactions of the nitryl halides are mostly similar: nitryl fluoride (FNO) and nitryl chloride (ClNO) are likewise reactive gases and vigorous"
"bromides may lead to and ions, or in a chloride solution, they may produce species like or via equilibrium reactions with the chlorides. Oxidation of the element with dichromate (in nitric acid solution) showed that adding chloride turned the astatine into a molecule likely to be either AtCl or AtOCl. Similarly, or may be produced. The polyhalides PdAtI, CsAtI, TlAtI, and PbAtI are known or presumed to have been precipitated. In a plasma ion source mass spectrometer, the ions [AtI], [AtBr], and [AtCl] have been formed by introducing lighter halogen vapors into a helium-filled cell containing astatine, supporting the existence"
"sample of chlorine contains 75.8% chlorine-35 and 24.2% chlorine-37, giving an average atomic mass of 35.5 atomic mass units. According to generally accepted cosmology theory, only isotopes of hydrogen and helium, traces of some isotopes of lithium and beryllium, and perhaps some boron, were created at the Big Bang, while all other nuclides were synthesized later, in stars and supernovae, and in interactions between energetic particles such as cosmic rays, and previously produced nuclides. (See nucleosynthesis for details of the various processes thought responsible for isotope production.) The respective abundances of isotopes on Earth result from the quantities formed by"
"Hypobromite The hypobromite ion, also called alkaline bromine water, is BrO. Bromine is in the +1 oxidation state. Hypobromite is the bromine compound analogous to hypochlorites found in common bleaches, and in immune cells. In many ways, hypobromite functions in the same manner as hypochlorite, and is also used as a germicide and antiparasitic in both industrial applications, and in the immune system. Hypobromite salts form upon treating bromine with aqueous alkali, such as sodium or potassium hydroxide. At 20 °C the reaction is rapid. In this reaction the bromine disproportionates (some undergoes reduction and some oxidation) from oxidation state"
"bromate and bromide above the pKa of HBrO. These reactions of bromine are analogous to those of chlorine forming hypochlorite and chlorate. The corresponding chlorine reaction 1 (to form ClO) is fast at 20 °C and reaction 2 (to form ) is slow at 20 °C and fast at 70 °C. A hypobromite is a compound that contains this anion. Examples include sodium hypobromite and potassium hypobromite. Bromide from the diet, naturally present in the blood, is used by eosinophils, white blood cells of the granulocyte class, specialized for dealing with multi-cellular parasites. These cells react the bromide with peroxide"
"its outer shell. Corresponding to periodic trends, it is intermediate in electronegativity between fluorine and bromine (F: 3.98, Cl: 3.16, Br: 2.96, I: 2.66), and is less reactive than fluorine and more reactive than bromine. It is also a weaker oxidising agent than fluorine, but a stronger one than bromine. Conversely, the chloride ion is a weaker reducing agent than bromide, but a stronger one than fluoride. It is intermediate in atomic radius between fluorine and bromine, and this leads to many of its atomic properties similarly continuing the trend from iodine to bromine upward, such as first ionisation energy,"
"that it is an actual element. Chlorine combined with hydrochloric acid, as well as sulfuric acid in certain instances created chlorine gas a poisonous gas during World War I. It displaced oxygen in contaminated areas and replaced common oxygenated air with the toxic chlorine gas. In which the gas would burn human tissue externally and internally, especially the lungs making breathing difficult or impossible depending on level of contamination. Bromine was discovered in the 1820s by Antoine Jérôme Balard. Balard discovered bromine by passing chlorine gas through a sample of brine. He originally proposed the name ""muride"" for the new"
"such as xenon difluoride and cobalt(III) fluoride. Chlorination is generally highly exothermic. Both saturated and unsaturated compounds react directly with chlorine, the former usually requiring UV light to initiate homolysis of chlorine. Chlorination is conducted on a large scale industrially; major processes include routes to 1,2-dichloroethane (a precursor to PVC), as well as various chlorinated ethanes, as solvents. Bromination is more selective than chlorination because the reaction is less exothermic. Most commonly bromination is conducted by the addition of Br to alkenes. An example of bromination is the organic synthesis of the anesthetic halothane from trichloroethylene: Organobromine compounds are the"
"tend to have symptoms similar to arthritis. Chlorine gas is highly toxic. Breathing in chlorine at a concentration of 3 parts per million can rapidly cause a toxic reaction. Breathing in chlorine at a concentration of 50 parts per million is highly dangerous. Breathing in chlorine at a concentration of 500 parts per million for a few minutes is lethal. Breathing in chlorine gas is highly painful. Pure bromine is somewhat toxic, but less toxic than fluorine and chlorine. One hundred milligrams of bromine is lethal. Bromide anions are also toxic, but less so than bromine. Bromide has a lethal"
"bromide: The bromide ions are oxidized with the hypochlorous acid that was formed from the initial BCDMH: This produces more hypobromous acid. However, the hypochlorous acid itself does act directly as a disinfectant in the process. This compound is prepared by first brominating, then chlorinating 5,5-dimethylhydantoin: BCDMH 1-Bromo-3-chloro-5,5-dimethylhydantoin (BCDMH or bromochlorodimethylhydantoin) is a chemical structurally related to hydantoin. It is a white crystalline compound with a slight bromine and acetone odor and is insoluble in water, but soluble in acetone. BCDMH is an excellent source of both chlorine and bromine as it reacts slowly with water releasing hypochlorous acid and"
"sulfuric acid and bleaching powder to natural brine. However, in modern times, bromine is produced by electrolysis, a method invented by Herbert Dow. It is also possible to produce bromine by passing chlorine through seawater and then passing air through the seawater. In 2003, 22,000 metric tons of iodine were produced. Chile produces 40% of all iodine produced, Japan produces 30%, and smaller amounts are produced in Russia and the United States. Until the 1950s, iodine was extracted from kelp. However, in modern times, iodine is produced in other ways. One way that iodine is produced is by mixing sulfur"
"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"
"to the nitrogen atom, especially in the presence of a mercury(II) sulfate catalyst. In contrast to the nitration and sulfonation, the direct bromination and chlorination of pyridine proceed well. The reaction of pyridine with molecular bromine in sulfuric acid at 130 °C readily produced 3-bromopyridine. The yield is lower for 3-chloropyridine upon chlorination with molecular chlorine in the presence of aluminium chloride at 100 °C. Both 2-bromopyridine and 2-chloropyridine can be produced by direct reaction with halogen with a palladium(II) chloride catalyst. In contrast to benzene, pyridine efficiently supports several nucleophilic substitutions. The reason for this is relatively lower electron"
"Bromate The bromate anion, BrO, is a bromine-based oxoanion. A bromate is a chemical compound that contains this ion. Examples of bromates include sodium bromate, (), and potassium bromate, (). Bromates are formed many different ways in municipal drinking water. The most common is the reaction of ozone and bromide: Electrochemical processes, such as electrolysis of brine without a membrane operating to form hypochlorite, will also produce bromate when bromide ion is present in the brine solution. Photoactivation (sunlight exposure) will encourage liquid or gaseous bromine to generate bromate in bromide-containing water. In laboratories bromates can be synthesized by dissolving"
"bromine (Br). While there are natural sources for all of these species, the concentrations of chlorine and bromine increased markedly in recent decades because of the release of large quantities of man-made organohalogen compounds, especially chlorofluorocarbons (CFCs) and bromofluorocarbons. These highly stable compounds are capable of surviving the rise to the stratosphere, where Cl and Br radicals are liberated by the action of ultraviolet light. Each radical is then free to initiate and catalyze a chain reaction capable of breaking down over 100,000 ozone molecules. By 2009, nitrous oxide was the largest ozone-depleting substance (ODS) emitted through human activities. The"
"Pyridinium perbromide Pyridinium perbromide (also called pyridinium bromide perbromide, pyridine hydrobromide perbromide, or pyridinium tribromide) is an organic chemical composed of a pyridinium cation and a tribromide anion. It can also be considered as a complex containing pyridinium bromide—the salt of pyridine and hydrogen bromide—with an added bromine (Br). The chemical is a solid whose reactivity is similar to that of bromine. It is thus a strong oxidizing agent used as a source of electrophilic bromine in halogenation reactions. The analogous quinoline compound behaves similarly. Pyridinium tribromide can be obtained by reacting pyridinium hydrobromide with bromine or thionyl bromide. Pyridinium"
"Chloride The chloride ion is the anion (negatively charged ion) Cl. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride salts such as sodium chloride are often very soluble in water. It is an essential electrolyte located in all body fluids responsible for maintaining acid/base balance, transmitting nerve impulses and regulating fluid in and out of cells. Less frequently, the word ""chloride"" may also form part of the ""common"" name of chemical compounds in which one or more chlorine atoms"
"Bromine monochloride Bromine monochloride, also called bromine(I) chloride, bromochloride, and bromine chloride, is an interhalogen inorganic compound with chemical formula BrCl. It is a very reactive golden yellow gas with boiling point 5 °C and melting point −66 °C. Its CAS number is 13863-41-7 and its EINECS number is 237-601-4. It is a strong oxidizing agent. Bromine monochloride is used in analytical chemistry in determining low levels of mercury, to quantitatively oxidize mercury in the sample to Hg(II) state. Bromine monochloride is used as a biocide, specifically as an algaecide, fungicide, and disinfectant, in industrial recirculating cooling water systems. Addition"