Bromine
3756
225963613
2008-07-16T06:05:12Z
Sephiroth BCR
621952
Reverted edits by [[Special:Contributions/74.138.165.85|74.138.165.85]] to last version by Atyndall (using [[WP:HG|Huggle]])
{{Redirect|Bromo}}
{{Elementbox_header | number=35 | symbol=Br | name=bromine | left=[[selenium]] | right=[[krypton]] | above=[[chlorine|Cl]] | below=[[iodine|I]] | color1=#ffff99 | color2=blue }}
{{Elementbox_series | [[halogen]]s }}
{{Elementbox_groupperiodblock | group=17 | period=4 | block=p }}
{{Elementbox_appearance_img | Br,35| gas/liquid: red-brown<br />solid: metallic luster }}
{{Elementbox_atomicmass_gpm | [[1 E-25 kg|79.904]][[List of elements by atomic mass|(1)]] }}
{{Elementbox_econfig | [[[argon|Ar]]] 4s<sup>2</sup> 3d<sup>10</sup> 4p<sup>5</sup> }}
{{Elementbox_epershell | 2, 8, 18, 7 }}
{{Elementbox_section_physicalprop | color1=#ffff99 | color2=blue }}
{{Elementbox_phase | [[liquid]] }}
{{Elementbox_density_gpcm3nrt | (Br<sub>2</sub>, liquid) 3.1028 }}
{{Elementbox_meltingpoint | k=265.8 | c=-7.2 | f=19 }}
{{Elementbox_boilingpoint | k=332.0 | c=58.8 | f=137.8 }}
{{Elementbox_criticalpoint | k=588 | mpa=10.34 }}
{{Elementbox_heatfusion_kjpmol | (Br<sub>2</sub>) 10.571 }}
{{Elementbox_heatvaporiz_kjpmol | (Br<sub>2</sub>) 29.96 }}
{{Elementbox_heatcapacity_jpmolkat25 | (Br<sub>2</sub>)<br />75.69 }}
{{Elementbox_vaporpressure_katpa | 185 | 201 | 220 | 244 | 276 | 332 | comment= }}
{{Elementbox_section_atomicprop | color1=#ffff99 | color2=blue }}
{{Elementbox_crystalstruct | orthorhombic }}
{{Elementbox_oxistates | 5, 4,<ref>{{cite web|url=http://www.webelements.com/webelements/compounds/text/Br/Br1O2-21255834.html|title=Bromine: bromine(IV) oxide compound data|accessdate=2007-12-10|publisher=WebElements.com}}</ref> 3,<ref>{{cite web|url=http://www.webelements.com/webelements/compounds/text/Br/Br1F3-7787715.html|title=Bromine: bromine(III) fluoride compound data|accessdate=2007-12-10|publisher=WebElements.com}}</ref> 1, -1<br />(strongly [[acid]]ic oxide) }}
{{Elementbox_electroneg_pauling | 2.96 }}
{{Elementbox_ionizationenergies4 | 1139.9 | 2103 | 3470 }}
{{Elementbox_atomicradius_pm | [[1 E-10 m|115]] }}
{{Elementbox_atomicradiuscalc_pm | [[1 E-11 m|94]] }}
{{Elementbox_covalentradius_pm | [[1 E-10 m|114]] }}
{{Elementbox_vanderwaalsrad_pm | [[1 E-10 m|185]] }}
{{Elementbox_section_miscellaneous | color1=#ffff99 | color2=blue }}
{{Elementbox_magnetic | nonmagnetic }}
{{Elementbox_eresist_ohmmat20 | 7.8×10<sup>10</sup> }}
{{Elementbox_thermalcond_wpmkat300k | 0.122 }}
{{Elementbox_speedofsound_mps | (20 °C) ? 206 }}
{{Elementbox_cas_number | 7726-95-6 }}
{{Elementbox_isotopes_begin | color1=#ffff99 | color2=blue }}
{{Elementbox_isotopes_stable | mn=79 | sym=Br | na=50.69% | n=44 }}
{{Elementbox_isotopes_stable | mn=81 | sym=Br | na=49.31% | n=46 }}
{{Elementbox_isotopes_end}}
{{Elementbox_footer | color1=#ffff99 | color2=blue }}
'''Bromine''' ({{pronEng|ˈbroʊmiːn/, /ˈbroʊmaɪn/, /ˈbroʊmɪn}}, {{lang-el|βρῶμος, ''brómos''}}, meaning "stench (of he-goats)" <ref name="Gemoll"> Gemoll W, Vretska K: Griechisch-Deutsches Schul- und Handwörterbuch ("Greek-German dictionary"), 9th ed., published by [http://www.oebvhpt.at/ öbvhpt], ISBN 3-209-00108-1</ref>), is a [[chemical element]] with the symbol '''Br''' and [[atomic number]] 35. A [[halogen]] element, bromine is a red [[Volatility (chemistry)|volatile]] liquid at [[Standard conditions for temperature and pressure|standard room temperature]] that is intermediate in reactivity between [[chlorine]] and [[iodine]]. Bromine vapours are [[corrosive]] and [[toxic]]. Approximately 730,000,000 kg was produced in 1993.<ref name=Ullmann>Jack F. Mills "Bromine" in Ullmann's Encyclopedia of Chemical Technology Wiley-VCH Verlag; Weinheim, 2002. DOI: 10.1002/14356007.a04_391</ref> The main applications for bromine are in [[fire retardant]]s and fine chemicals.
== History ==
{{Expand-section|date=December 2007}}
Bromine was discovered independently by two chemists [[Antoine Jerome Balard|Antoine Balard]] and [[Carl Jacob Löwig]] in 1825 and 1826.
Balard found bromide salts in the ash of sea weed from the [[salt marsh]]es of [[Montpellier]] in [[1826]]. The seaweed was used to produce iodine, but also contained bromine.
[[Carl Jacob Löwig]] working at the laboratory of [[Leopold Gmelin]] produced elemental bromine by reacting mineral salts, which contained bromides, with chlorine gas. The publication of the results was delayed and Balard published his results first.
Bromine was not produced in quantity until [[1860]]. The French chemist and physicist [[Joseph-Louis Gay-Lussac]] suggested the name bromine due to the characteristic smell of the vapors. Some also suggest that it may have been discovered by [[Bernard Courtois]], the man who discovered iodine.<ref>{{cite web
| url = http://www.vanderkrogt.net/elements/elem/br.html
| title = Bromine
| publisher = vanderkrogt.net }}</ref>
[[Potassium bromide]] and [[sodium bromide]] were used as anticonvulsants and sedatives in the late 19th and early 20th centuries, until it was gradually superseded by [[chloral hydrate]] and then the [[barbiturate]]s.
== Isotopes ==
{{main|Isotopes of bromine}}
{{Expand-section|date=December 2007}}
Bromine has 2 stable isotopes: Br-79 (50.69%) and Br-81 (49.31%). At least another
23<ref>{{cite book | author=GE Nuclear Energy | title=Chart of the Nuclides, 14th Edition | year=1989 }}</ref>
isotopes are known to exist. Many of the bromine isotopes are fission products. Several of the heavier bromine isotopes from fission are delayed neutron emitters. All of the radioactive bromine isotopes are relatively short lived. The longest half life is the neutron deficient Br-77 at 2.376 days. The longest half life on the neutron rich side is Br-82 at 1.471 days. A number of the bromine isotopes exhibit metastable isomers. Stable Br-79 exhibits a radioactive isomer, with a half life of 4.86 seconds. It decays by isomeric transition to the stable ground state.
== Notable characteristics ==
Bromine is the only liquid [[nonmetal]]lic element at room temperature and one of only six elements on the periodic table that are liquid at or close to room temperature. The pure chemical element has the physical form of a [[diatomic molecule]], Br<sub>2</sub>. It is a dense, mobile, reddish-brown liquid, that evaporates easily at [[standard temperature and pressure]]s to give a red vapor (its color resembles [[nitrogen dioxide]]) that has a strong disagreeable odor resembling that of [[chlorine]]. Bromine is a [[halogen]], and is less reactive than [[chlorine]] and more reactive than [[iodine]]. Bromine is slightly [[solubility|soluble]] in [[water (molecule)|water]], and highly soluble in [[carbon disulfide]], [[aliphatic]] [[alcohol]]s (such as [[methanol]]), and [[acetic acid]]. It [[chemical bond|bonds]] easily with many elements and has a strong [[Bleach (chemical)|bleaching]] action. Bromine, like chlorine, is also used in pool maintenance.
Certain bromine-related compounds have been evaluated to have an [[ozone depletion potential]] or bioaccumulate in living organisms. As a result many industrial bromine compounds are no longer manufactured, are being restricted, or scheduled for phasing out.
Bromine is a powerful [[oxidizing agent]]. It reacts vigorously with metals, especially in the presence of water, as well as most organic compounds, especially upon [[photochemistry|illumination]].
Bromine has no known role in human health. Organobromine compounds do occur naturally, a famous example being [[Tyrian purple]]. Most organobromine compounds in nature arise via the action of [[vanadium bromoperoxidase]].
== Occurrence and production ==
:''See also [[:Category:Halide minerals|Halide minerals]].''
[[Image:Bromine - world production trend.svg|thumb|left|World bromine production trend]]
The diatomic element Br<sub>2</sub> does not occur naturally. Instead, bromine exists exclusively as [[Bromide|bromide salts]] in diffuse amounts in [[crust (geology)|crustal]] rock. Due to [[leaching]], bromide salts have accumulated in sea water (85 [[part per million|ppm]]), but at a lower concentration than chloride. Bromine may be economically recovered from bromide-rich brine wells and from the [[Dead Sea]] waters (up to 50000 ppm).
Approximately 720,000 metric tons (worth around US$2.5 billion) of bromine are produced per year (2007) worldwide with the [[United States]], [[China]] and [[Israel]] being the primary producers. Bromine production has increased sixfold since the 1960s. The largest bromine reserve in the United States is located in [[Columbia County, Arkansas|Columbia]] and [[Union County, Arkansas]], U.S.<ref>[http://www.cals.lib.ar.us/butlercenter/lesson_plans/lesson%20plans/Lesson%20plans-retained/Bromine.pdf Bromine:An Important Arkansas Industry], Butler Center for Arkansas Studies</ref> China's bromine reserves are located in the [[Shandong Province]] and Israel's bromine reserves are contained in the waters of the [[Dead Sea]]. The bromide-rich brines are treated with chlorine gas, flushing through with air. In this treatment, bromide anions are oxidized to bromine by the chlorine gas.
:2 Br<sup>−</sup> + Cl<sub>2</sub> → 2 Cl<sup>−</sup> + Br<sub>2</sub>
Because of its commercial availability and long shelf-life, bromine is not typically prepared. Small amounts of bromine can however be generated through the reaction of solid [[sodium bromide]] with concentrated [[sulfuric acid]] (H<sub>2</sub>SO<sub>4</sub>). The first stage is formation of [[hydrogen bromide]] (HBr), which is a gas, but under the reaction conditions some of the HBr is oxidized further by the sulfuric acid to form bromine (Br<sub>2</sub>) and [[sulfur dioxide]] (SO<sub>2</sub>).
:NaBr (s) + H<sub>2</sub>SO<sub>4</sub> (aq) → HBr (aq) + NaHSO<sub>4</sub> (aq)
:2 HBr (aq) + H<sub>2</sub>SO<sub>4</sub> (aq) → Br<sub>2</sub> (g) + SO<sub>2</sub> (g) + 2 H<sub>2</sub>O (l)
Similar alternatives, such as the use of dilute [[hydrochloric acid]] with [[sodium hypochlorite]], are also available. The most important thing is that the [[anion]] of the [[acid]] (in the above examples, [[sulfate]] and [[chloride]], respectively) be more [[electronegative]] than bromine, allowing the [[substitution reaction]] to occur.
==Compounds==
{{Expand-section|date=December 2007}}
{{seealso|Category:Bromine compounds}}
====Organic chemistry====
Organic compounds are brominated by either [[Addition reaction|addition]] or [[Substitution (chemistry)|substitution reactions]]. Bromine undergoes electrophilic addition to the double-bonds of [[alkene]]s, via a cyclic bromonium intermediate. In non-aqueous solvents such as [[carbon disulfide]], this affords the di-bromo product. For example, reaction with [[ethylene]] will produce [[1,2-Dibromoethane|1,2-dibromoethane]]. Bromine also undergoes electrophilic addition to [[phenol]]s and [[aniline]]s. When used as bromine water, the corresponding [[halohydrin formation reaction|bromohydrin is formed]] instead. So reliable is the reactivity of bromine that bromine water is employed as a reagent to test for the presence alkenes, phenols, and anilines. Like the other halogens, bromine participates in [[free radical reaction]]s. For example hydrocarbons are brominated upon treatment with bromine in the presence of light.
Bromine, sometimes with a catalytic amount of [[phosphorus]], easily brominates [[carboxylic acid]]s at the α-position. This method, the [[Hell-Volhard-Zelinsky reaction]], is the basis of the commercial route to [[bromoacetic acid]].
[[N-Bromosuccinimide|''N''-Bromosuccinimide]] is commonly used as a substitute for elemental bromine, being easier to handle, and reacting more mildly and thus more selectively.
Organic bromides are often preferable relative to the less reactive chlorides and more expensive iodide-containing reagents. Thus, [[Grignard]] and organolithium compound are most often generated from the corresponding bromides.
====Inorganic chemistry====
Bromine is an oxidizer, and it will oxidize [[iodide]] ions to iodine, being itself reduced to [[bromide]]:
: Br<sub>2</sub> + 2 I<sup>−</sup> → 2 Br<sup>−</sup> + I<sub>2</sub>
Bromine will also oxidize metals and metaloids to the corresponding bromides. [[Anhydrous]] bromine is less reactive toward many metals than hydrated bromine, however. Dry bromine reacts vigorously with [[aluminium]], [[titanium]], [[mercury (element)|mercury]] as well as [[alkaline earth metal|alkaline earth]]s and [[alkali metal]]s.
==Applications==
A wide variety of organobromine compounds are used in [[industry]]. Some are prepared from bromine and others are prepared from [[hydrogen bromide]], which is obtained by burning [[hydrogen]] in bromine.<ref name=Ullmann/>
Illustrative of the addition reaction<ref>{{OrgSynth | author = N. A. Khan, F. E. Deatherage, and J. B. Brown | title = Stearolic Acid | collvol = 4 | collvolpages = 851| year = 1963 | prep = CV4P0851}}</ref> is the preparation of [[1,2-Dibromoethane]], the organobromine compound produced in the largest amounts:
:C<sub>2</sub>H<sub>4</sub> + Br<sub>2</sub> → CH<sub>2</sub>BrCH<sub>2</sub>Br
Ethylene bromide is an additive in gasolines containing lead anti-[[engine knocking]] agents. It scavenges lead by forming volatile lead bromide, which is exhausted from the engine. This application has declined since the 1970s due to environmental regulations. Ethylene bromide is also used as a fumigant, but again this application is declining.
[[Brominated flame retardant]]s represent a commodity of growing importance. Specific compound used produced for this purpose include [[tetrabromobisphenol A]], [[decabromodiphenyl ether]], and [[vinyl bromide]].
The bromides of calcium, sodium, and zinc account for a sizable part of the bromine market. These salts form dense solutions in water that are used as [[drilling fluid]]s.
Miscellaneous uses:
*Several [[dye]]s, agrichemicals, and [[pharmaceutical]]s are organobromine compounds. 1-Bromo-3-chloropropane, 1-bromoethylbenzene, and 1-bromoalkanes are prepared by the [[markovnikov rule|antimarkovnikov addition]] of HBr to alkenes. [[Ethidium bromide]], EtBr, is used as a [[DNA]] stain in [[gel electrophoresis]].
* Bromine is also used in for the production of [[brominated vegetable oil]], which is used as an [[emulsifier]] in many [[citrus]]-flavored [[soft drinks]].
* High [[refractive index]] compounds
* [[Water purification]] compounds, [[Disinfectants]]
* Potassium bromide is used in some photographic developers to inhibit the formation of fog (undesired reduction of silver).
== Safety ==
Elemental bromine is toxic and [[irritant|causes burns]]. As an [[oxidizing]] agent, it is incompatible with most organic and inorganic compounds. Care needs to taken when transporting bromine, it is commonly carried in steel tanks lined with lead, supported by strong metal frames.
When certain ionic compounds containing bromine are mixed with potassium permanganate (KMnO<sub>4</sub>), they will form a pale brown cloud of bromine gas. This gas smells like bleach and is very irritating to the mucus membranes. Upon exposure, one should move to fresh air immediately. If symptoms arise, medical attention is needed.
== References ==
<references/>
* [http://periodic.lanl.gov/elements/35.html Los Alamos National Laboratory – Bromine]
== External links ==
{{Commons|Bromine}}
{{wiktionary|bromine}}
* [http://www.webelements.com/webelements/elements/text/Br/index.html WebElements.com – Bromine]
* [http://www.theodoregray.com/PeriodicTable/Elements/035/index.s7.html Theodoregray.com – Bromine]
* [http://minerals.usgs.gov/minerals/pubs/commodity/bromine USGS Minerals Information: Bromine]
* [http://www.bsef.com/ Bromine Science and Environmental Forum (BSEF)]
* [http://twt.mpei.ac.ru/MAS/Worksheets/HEDH/5-5-14-43-54/Tab-5-5-14-54-BROMINE-Thermal.mcd Thermal Conductivity of BROMINE]
* [http://twt.mpei.ac.ru/MAS/Worksheets/HEDH/5-5-14-43-54/Tab-5-5-14-54-BROMINE-Viscosity.mcd Viscisity of BROMINE]
{{diatomicelements}}
{{compact periodic table}}
[[Category:Chemical elements]]
[[Category:Halogens]]
[[Category:Bromine|*]]
[[af:Broom]]
[[ar:بروم]]
[[bn:ব্রোমিন]]
[[be:Бром]]
[[bs:Brom]]
[[bg:Бром]]
[[ca:Brom]]
[[cv:Бром]]
[[cs:Brom]]
[[co:Bromu]]
[[cy:Bromin]]
[[da:Brom]]
[[de:Brom]]
[[et:Broom]]
[[el:Βρώμιο]]
[[es:Bromo]]
[[eo:Bromo]]
[[eu:Bromo]]
[[fa:برم]]
[[fr:Brome]]
[[fur:Brom]]
[[ga:Bróimín]]
[[gv:Bromeen]]
[[gl:Bromo]]
[[ko:브로민]]
[[hy:Բրոմ]]
[[hi:ब्रोमिन]]
[[hr:Brom]]
[[io:Bromo]]
[[id:Brom]]
[[is:Bróm]]
[[it:Bromo]]
[[he:ברום]]
[[jv:Brom]]
[[sw:Bromi]]
[[ht:Bwòm]]
[[la:Bromum]]
[[lv:Broms]]
[[lb:Brom]]
[[lt:Bromas]]
[[jbo:xunkliru]]
[[hu:Bróm]]
[[mk:Бром]]
[[mi:Pūkane]]
[[mr:ब्रोमिन]]
[[nl:Broom]]
[[ja:臭素]]
[[no:Brom]]
[[nn:Brom]]
[[oc:Bròme]]
[[uz:Brom]]
[[pl:Brom]]
[[pt:Bromo]]
[[ro:Brom]]
[[qu:Bromu]]
[[ru:Бром]]
[[simple:Bromine]]
[[sk:Bróm]]
[[sl:Brom]]
[[sr:Бром]]
[[sh:Brom]]
[[stq:Bromium]]
[[fi:Bromi]]
[[sv:Brom]]
[[ta:புரோமின்]]
[[th:โบรมีน]]
[[vi:Brôm]]
[[tg:Бром]]
[[tr:Brom]]
[[uk:Бром]]
[[zh-yue:溴]]
[[zh:溴]]