Name: Bromine
Symbol: Br
Atomic Number: 35
Atomic Weight: 79.904000
Family:  Halogens
CAS RN: 7726-95-6
Description: A heavy, volatile, reddish-brown liquid with a choking, irritating odor; causes tears
State (25C): Liquid
Oxidation states: 1, +5

Molar Volume: 25.62 cm3/mole
Valence Electrons: 4p5

Boiling Point:  332.4K, 59.25C, 138.65F
Melting Point:
266.05K, -7.1C, 19.2F
Electrons Energy Level: 2, 8, 18, 7
Isotopes: 25 + 2 Stable
Heat of Vaporization: 15.438 kJ/mol
Heat of Fusion: 5.286 kJ/mol
Density: 3.119g/cm3 @ 300K
Specific Heat: 0.473 J/gK
Atomic Radius: 1.12
Ionic Radius: 1.96
Electronegativity: 2.96 (Pauling); 2.74 (Allrod Rochow)
Vapor Pressure: 5800 Pa @ -7.1C
Bromine is a reddish-brown fuming liquid at room temperature with a very disagreeable chlorine-like smell.  In fact its name is derived from the Greek bromos or "stench".  The only nonmetallic element that is a liquid at normal room temperatures, Bromine was produced by Carl Lwig, a young chemistry student, the summer before starting his freshman year at Heidelberg.  When he showed his professor, Leopold Gmelin, the red, smelly liquid he had produced, Gmelin realized that this was an unknown substance and encouraged Lwig to produce more of it so they could study it in detail.   Unfortunately, winter exams and the holidays delayed Lwig's work long enough for another chemist, Antoine-Jrme Balard, to publish a paper in 1826 describing the new element he had isolated in pure form at the salt marshes of Monpellier.  It 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.

Most Bromine is produced by displacement from ordinary sea water. Chlorine (which is more active) is generally used to dislodge the Bromine from various compounds in the water. Before leaded gasolines were removed from the market, Bromine was used in an additive to help prevent engine "knocking". Production now is chiefly devoted to dyes, disinfectants and photographic chemicals.






1s2 2s2p6 3s2p6d10 4s2p5


Bromine is the only liquid nonmetallic  element at room temperature and one of five elements on the period table that are liquid at or close to room temperature.   The pure chemical element has the physical form of a diatomic molecule, Br2.   It is a heavy, mobile, reddish-brown liquid, that evaporates easily at standard temperature and pressues (273oK & 1 Atm.) in a red vapor (its color resembles Nitrogen Dioxide, NO2) that has a strong disagreeable odor resembling that of Chlorine.  A halogen, Bromine resembles Chlorine chemically but is less active.  It is more active than Iodine, however.  Bromine is slightly soluble in water, and highly soluble in Carbon Disulfide, CS2, aliphatic alchohols (such as Methanol (CH3OH), and Acetic Acid, CH3COOH.  It bonds easily with many elements and has a strong bleaching action.

2s2 2p6
3s2 3p6 3d10
4s2 4p5

Bromine is highly reactive and is a powerful oxidizing agent in the presence of water.   It reacts vigorously with Amines, Alkenes and Phenols as well as aliphatic and Aromatic Hydrocarbons, Ketones and Acids (these are brominated by either addition or substitution reactions).  With many of the metals and elements, anhydrous Bromine is less reactive than hydrated Bromine; however, dry Bromine reacts vigorously with Aluminum, Titanium, Mercury, as well as alkaline earth metals and alkaline metals.

Elemental Bromine is used to manufacture a wide variety of Bromine compounds used in industry and agriculture.  Traditionally the largest use of bromine was in the production of 1,2-Dibromoethane which in turn was used as a gasoline anti-knock agent for leaded gasolines before they were largely phased out due to environmental considerations.

Bromine is also used in the manufacture of fumigants, brominated flame-retardants, water purification compounds, dyes, medicines, sanitizers, imorganic bromides for photography, etc.  It is also used to form intermediates in organic synthesis, where it is preferred to Iodine due to its much lower cost.

Bromine is used to make brominated vegetable oil, which is used as an emulsifier in many citrus-flavored soft drinks.

Aqueous Bromine is orange and can be used in tests for Alkenes and Phenols.


Bromine occurs in nature as bromide salts in very diffuse amounts in crustal rock.   Due to leaching, bromide salts have accumulated in sea water (85 ppm), and may be economically recovered from brine wells and the Dead Sea (up to 5000 ppm).  Due to its contribution to Ozone depletion in Earth's atmosphere, Bromine has been evaluated to have an Ozone depletion potential of 60 when compared to Chlorine.

Approximately 500 million kilograms ($350 million USD) of Bromine are produced per year (2001) worldwide with the United States and Israel being the primary producers.  The largest Bromine reserve in the United States is located in Columbia and Union County, Arkansas.


40px-Skull_and_crossbones.svg.jpg (1420 bytes) Elemental Bromine is a strong irritant and, in concentrated form, will produce painful blisters on exposed skin and especially mucous membranes.  Even low concentrations of Bromine vapor (from 10 ppm) can affect breathing, and inhalation of significant amounts of Bromine can seriously damage the respiratory system.

It is the only non-metal that is a liquid at normal room conditions. Bromine on the skin causes painful burns that heal very slowly.  It is an element to be treated with the utmost respect in the laboratory.  Accordingly, one should always wear safety gogglesand ensure adequate ventilation when handling Bromine.

In laboratory settings, bromine should always be kept separate from Acetone, CH3COCH3, as the two chemicals will react and create Bromoacetone, a potentially hazardous lachrymatory agent.

Elemental Bromine is a hazardous material.  It causes severe burns when it comes in contact with the skin and its vapor irritates the eyes, nose and throat.  Most of the Bromine produced in the United States was used in the manufacture of Ethylene Dibromide(C2H4Br2), a chemical added to leaded gasolines that prevented the accumulation of lead compounds within the engine.  With the discontinuation of leaded gasolines in favor of unleaded gasolines, the demand for Bromine has been greatly reduced.  Silver Bromide (AgBr), a chemical used in photography, now accounts for the largest use of Bromine.  Other Bromine compounds are used in fumigants, in flameproofing agents and in some compounds used to purify water.  Tyrian purple, an expensive purple dye known to ancient civilizations, was produced from an organic Bromine compound secreted from a sea mussel known as the murex.


Aluminum Bromide (AlBr3) Ammonium Bromide (NH4Br)
Bromine Monofluoride (BrF) Bromine Pentafluoride (BrF5)
Bromine trifluoride (BrF3) Tetrabromomethane (CBr4)
Hydrobromic Acid (HBr) Iron (III) Bromide (FeBr3)
Lithium Bromide (LiBr) Phosphorus Pentabromide (PBr5)
Phosphorus Tribromide (PBr3) Potassium Bromide (KBr)
Potassium Bromate (KBrO3) Silver Bromide (AgBr)
Sodium Bromide (NaBr) Sodium Bromate (NaBrO3)


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Isotope Atomic Mass Half-Life
Br67 66.965  
Br68 67.958 <1.5 us
Br69 68.95 <100 ns
Br70 69.945 79.1 ms
Br71 70.939 21.4 seconds
Br72 71.936 78.6 seconds
Br73 72.932 3.4 minutes
Br74 73.9299 25.4 minutes
Br75 74.9258 96.7 minutes
Br76 75.9245 16.2 hours
Br77 76.9214 57.036 hours
Br78 77.9212 6.46 minutes
Br79 78.9183 Stable
Br80 79.9185 17.68 minutes
Br81 80.9163 Stable
Br82 81.9168 35.3 hours
Br83 82.9152 2.4 hours
Br84 83.9165 31.8 minutes
Br85 84.9156 2.9 minutes
Br86 85.9188 55.1 seconds
Br87 86.9207 55.6 seconds
Br88 87.9241 16.34 seconds
Br89 88.9264 4.348 seconds
Br90 89.9306 1.91 seconds
Br91 90.934 0.541 seconds
Br92 91.9393 0.343 seconds
Br93 92.943 102 ms
Br94 93.949 70 ms

(Gr. bromos, stench) Discovered by Balard in 1826, but not prepared in quantity until 1860.  A member of the halogen group of elements, it is obtained from natural brines from wells in Michigan and Arkansas.  Little bromine is extracted today from seawater, which contains only about 85 ppm.  Bromine is the only liquid nonmetallic element.  It is a heavy, mobile, reddish-brown liquid, volatilizing readily at room temperature to a red vapor with a strong disagreeable odor, resembling chlorine, and having a very irritating effect on the eyes and throat; it is readily soluble in water or carbon disulfide, forming a red solution, is less active than chlorine but more so than iodine; it unites readily with many elements and has a bleaching action; when spilled on the skin it produces painful sores.  It presents a serious health hazard, and maximum safety precautions should be taken when handling it.  Much of the bromine output in the U.S. was used in the production of ethylene dibromide, a lead scavenger used in making gasoline antiknock compounds.  Lead in gasoline, however, has been drastically reduced, due to environmental considerations.  This will greatly affect future production of bromine.  Bromine is also used in making fumigants, flameproofing agents, water purification compounds, dyes, medicinals, sanitizers, inorganic bromides for photography, etc. Organic bromides are also important.

Source: CRC Handbook of Chemistry and Physics, 1913-1995. David R. Lide, Editor in Chief. Author: C.R. Hammond

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Bromine Data

Atomic Radius (): 1.12
Atomic Volume cm3/mol : 23.5cm3/mol
Covalent Radius: 1.14
Crystal Structure: Orthorhombic
Ionic Radius: 1.96

Chemical Properties

Electrochemical Equivalents: 2.9812 g/amp-hr
Electron Work Function: unknown
Electronegativity: 2.96 (Pauling); 2.74 (Allrod Rochow)
Heat of Fusion: 5.286 kJ/mol
Incompatibilities: Combustible Organics (sawdust, wood, cotton, straw, etc.), Oxidizable Material, Aqueous Ammonia, Hydrogen, Acetylene, Phosphorus, Aluminum, Titanium, Mercury, Potassium, other metals.
First Ionization Potential: 11.814
Second Ionization Potential: 21.8
Third Ionization Potential: 36
Valence Electron Potential: -7.35
Ionization Energy (eV): 11.814 eV

Physical Properties

Atomic Mass Average: 79.904
Boiling Point: 332.4K, 59.25C, 138.65F
Melting Point: 266.05K, -7.1C, 19.2F
Heat of Vaporization: 15.438 kJ/mol
Coefficient of Lineal Thermal Expansion/K-1: N/A
Electrical Conductivity: unknown
Thermal Conductivity: 0.00122 W/cmK
Density: 3.119g/cm3 @ 300K
Enthalpy of Atomization: 111.7 kJ/mole @ 25C
Enthalpy of Fusion: 5.29 kJ/mole
Enthalpy of Vaporization: 15.46 kJ/mole
Flammability Class: Noncombustible Liquid
Molar Volume: 25.62 cm3/mole
Optical Refractive Index: 1.001132
Relative Gas Density (Air=1): 5.51
Specific Heat: 0.473 J/gK
Vapor Pressure: 5800 Pa @ -7.1C
Estimated Crustal Abundance: 2.4 milligrams per kilogram
Estimated Oceanic Abundance: 6.73101 milligrams per liter