Periodic Table > Bromine


Some elements exist in several different structural forms, called allotropes. Each allotrope has different physical properties.

For more information on the Visual Elements image see the Uses and properties section below.



A vertical column in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell.

A horizontal row in the periodic table. The atomic number of each element increases by one, reading from left to right.

Elements are organised into blocks by the orbital type in which the outer electrons are found. These blocks are named for the characteristic spectra they produce: sharp (s), principal (p), diffuse (d), and fundamental (f).

Atomic number
The number of protons in an atom.

Electron configuration
The arrangements of electrons above the last (closed shell) noble gas.

Melting point
The temperature at which the solid–liquid phase change occurs.

Boiling point
The temperature at which the liquid–gas phase change occurs.

The transition of a substance directly from the solid to the gas phase without passing through a liquid phase.

Density (g cm−3)
Density is the mass of a substance that would fill 1 cm3 at room temperature.

Relative atomic mass
The mass of an atom relative to that of carbon-12. This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists, the value given is the abundance weighted average.

Atoms of the same element with different numbers of neutrons.

CAS number
The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems.

Fact box

Group 17  Melting point −7.2°C, 19°F, 266 K 
Period Boiling point 58.8°C, 137.8°F, 332 K 
Block Density (g cm−3) 3.1028 
Atomic number 35  Relative atomic mass 79.904  
State at 20°C Liquid  Key isotopes 79Br 
Electron configuration [Ar] 3d104s24p5  CAS number 7726-95-6 
ChemSpider ID 4514586 ChemSpider is a free chemical structure database


Image explanation

Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture.


The description of the element in its natural form.

Biological role

The role of the element in humans, animals and plants.

Natural abundance

Where the element is most commonly found in nature, and how it is sourced commercially.

Uses and properties

Image explanation
The image intends to reflect the rich colour, liquidity and aromatic nature of the element.
Bromine is a deep-red, oily liquid with a sharp smell. It is toxic.
Bromine is used in many areas such as agricultural chemicals, dyestuffs, insecticides, pharmaceuticals and chemical intermediates. Some uses are being phased out for environmental reasons, but new uses continue to be found.

Bromine compounds can be used as flame retardants. They are added to furniture foam, plastic casings for electronics and textiles to make them less flammable. However, the use of bromine as a flame retardant has been phased out in the USA because of toxicity concerns.

Organobromides are used in halon fire extinguishers that are used to fight fires in places like museums, aeroplanes and tanks. Silver bromide is a chemical used in film photography.

Before leaded fuels were phased out, bromine was used to prepare 1,2-di-bromoethane, which was an anti-knock agent.
Biological role
Bromine is present in small amounts, as bromide, in all living things. However, it has no known biological role in humans. Bromine has an irritating effect on the eyes and throat, and produces painful sores when in contact with the skin.
Natural abundance
Bromine is extracted by electrolysis from natural bromine-rich brine deposits in the USA, Israel and China. It was the first element to be extracted from seawater, but this is now only economically viable at the Dead Sea, Israel, which is particularly rich in bromide (up to 0.5%).

Atomic radius, non-bonded
Half of the distance between two unbonded atoms of the same element when the electrostatic forces are balanced. These values were determined using several different methods.

Covalent radius
Half of the distance between two atoms within a single covalent bond. Values are given for typical oxidation number and coordination.

Electron affinity
The energy released when an electron is added to the neutral atom and a negative ion is formed.

Electronegativity (Pauling scale)
The tendency of an atom to attract electrons towards itself, expressed on a relative scale.

First ionisation energy
The minimum energy required to remove an electron from a neutral atom in its ground state.

Atomic data

Atomic radius, non-bonded (Å) 1.85 Covalent radius (Å) 1.17
Electron affinity (kJ mol−1) 324.537 Electronegativity
(Pauling scale)
Ionisation energies
(kJ mol−1)

Bond enthalpy (kJ mol−1)
A measure of how much energy is needed to break all of the bonds of the same type in one mole of gaseous molecules.

Bond enthalpies

Covalent bond Enthalpy (kJ mol−1) Found in
Br–Br 192.8 Br2
C–Br 285 general
Br–H 365.7 HBr


Data for this section been provided by the British Geological Survey.

Relative supply risk

An integrated supply risk index from 1 (very low risk) to 10 (very high risk). This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores.

Crustal abundance (ppm)

The number of atoms of the element per 1 million atoms of the Earth’s crust.

Recycling rate

The percentage of a commodity which is recycled. A higher recycling rate may reduce risk to supply.


The availability of suitable substitutes for a given commodity.
High = substitution not possible or very difficult.
Medium = substitution is possible but there may be an economic and/or performance impact
Low = substitution is possible with little or no economic and/or performance impact

Production concentration

The percentage of an element produced in the top producing country. The higher the value, the larger risk there is to supply.

Reserve distribution

The percentage of the world reserves located in the country with the largest reserves. The higher the value, the larger risk there is to supply.

Political stability of top producer

A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators.

Political stability of top reserve holder

A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators.

Supply risk

Relative supply risk 7
Crustal abundance (ppm) 0.88
Recycling rate (%) Unknown
Substitutability Unknown
Production concentration (%) 44.2
Reserve distribution (%) 63.6
Top 3 producers
  • 1) USA
  • 2) China
  • 3) Israel
Top 3 reserve holders
  • 1) USA
  • 2) China
  • 3) Spain
Political stability of top producer 56.6
Political stability of top reserve holder 56.6


Common oxidation states

The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Uncombined elements have an oxidation state of 0. The sum of the oxidation states within a compound or ion must equal the overall charge.


Atoms of the same element with different numbers of neutrons.

Key for isotopes

Half life
  y years
  d days
  h hours
  m minutes
  s seconds
Mode of decay
  α alpha particle emission
  β negative beta (electron) emission
  β+ positron emission
  EC orbital electron capture
  sf spontaneous fission
  ββ double beta emission
  ECEC double orbital electron capture

Oxidation states and isotopes

Common oxidation states 7, 5, 3, 1, -1
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  79Br 78.918 50.69
  81Br 80.916 49.31


Specific heat capacity (J kg−1 K−1)

Specific heat capacity is the amount of energy needed to change the temperature of a kilogram of a substance by 1 K.

Young's modulus

A measure of the stiffness of a substance. It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.

Shear modulus

A measure of how difficult it is to deform a material. It is given by the ratio of the shear stress to the shear strain.

Bulk modulus

A measure of how difficult it is to compress a substance. It is given by the ratio of the pressure on a body to the fractional decrease in volume.

Vapour pressure

A measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system.

Pressure and temperature data – advanced

Specific heat capacity
(J kg−1 K−1)
474 Young's modulus (GPa) Unknown
Shear modulus (GPa) Unknown Bulk modulus (GPa) 1.9
Vapour pressure  
Temperature (K)
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
Pressure (Pa)
- - - - - - - - - - -
  Help text not available for this section currently


Antoine-Jérôme Balard discovered bromine while investigating some salty water from Montpellier, France. He took the concentrated residue which remained after most of the brine had evaporated and passed chlorine gas into it. In so doing he liberated an orange-red liquid which he deduced was a new element. He sent an account of his findings to the French Academy’s journal in 1826.

A year earlier, a student at Heidelberg, Carl Löwig, had brought his professor a sample of bromine which he had produced from the waters of a natural spring near his home at Keruznach. He was asked to produce more of it, and while he was doing so Balard published his results and so became known at its discoverer.
  Help text not available for this section currently


Listen to Bromine Podcast
Transcript :

Chemistry in its element: bromine


You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry.

(End promo)

Chris Smith

Hello, welcome to Chemistry in its element where this week we're sniffing out the chemical that is named after the Greek word for stench and this substance has certainly kicked up a stink in its own right in its time because it makes holes in the ozone layer. But it's not all bad as it's also given us drugs, insecticides and fire extinguishers and to tell the story of element number 35, here's chemist and author John Emsley.

John Emsley

Fifty years ago bromine was produced on a massive scale and turned into lots of useful compounds. Photography relied on the light-sensitivity of silver bromide, doctors prescribed potassium bromide as a tranquiliser, leaded petrol needed dibromomethane to ensure the lead was removed via the exhaust gases, bromomethane was widely used to fumigate soil and storage facilities, and fire extinguishers contained volatile organobromine compounds. Today these uses have all but disappeared.

World production of liquid bromine once exceeded 300,000 tonnes per year, of which a significant part was produced by a plant on the coast of Anglesey in Wales, which closed in 2004. This extracted the element from sea water, which contains 65 p.p.m. of bromide, and was done by using chlorine gas to convert the bromide to bromine which was then removed by blowing air through the water.

The bromine story began with 24-year-old student Antoine-Jérôme Balard. He found that the salt residues left by evaporating brine from Montpellier, France, gave an oily red liquid when treated with acid. He realised this was a new element and reported it to the French Academy, who confirmed his discovery. When they realised it was chemically similar to chlorine and iodine they proposed the name bromine, based on the Greek word bromos meaning stench.

While some uses of bromine have declined because the products made from it are no longer needed, others have been discouraged because of the damage this element could cause to the ozone layer. Volatile organobromine compounds are capable of surviving in the atmosphere long enough to reach the upper ozone layer where their bromine atoms are 50 times more damaging than the chlorine atoms - which are the main threat, coming as they did from the widely used chlorofluorocarbons, the CFCs. The Montreal Protocol which outlawed the CFCs sought also to ban the use of all volatile organobromines by 2010, and this restriction especially applied to the fumigant bromomethane and compounds such as CBrClF2 which were in fire extinguishers for electrical fires or those in confined spaces.

Bromomethane was a particular cause for concern but banning it has proved impossible because it has some uses for which alternatives have not been found. Often referred to as methyl bromide, CH3Br (boiling point 3.5oC), this has been widely employed to kill pests in the soil, in storage facilities, and to treat wood before it is exported. In the soil it kills nematodes, insects, bacteria, mites and fungi which threaten crops such as seed crops, lettuce, strawberries, grapes, and flowers such as carnations and chrysanthemums.

In fact bromomethane is not quite so threatening as it first appears. Environmental research uncovered the unexpected result that half the bromomethane sprayed on soil never evaporates into the air because it is consumed by bacteria. Nor are man-made organobromines the main source of these compounds in the atmosphere. Marine plankton and algae release around half a million tonnes of various bromomethanes a year and in particularly tribromomethane (aka bromoform, CHBr3).

Even more surprising has been the discovery that something in the oceans is making pentabromodiphenyl ether. This has been used as a fire-retardant, and when in 2005 it was found to be present in whale blubber it was at first thought to be the man-made variety. However, the carbon atoms it contained had detectable amounts of 14C meaning that they were of recent origin, whereas the fire retardant is made entirely from fossil resources and contains no 14C. Another complex bromine compound from the sea is the purple dye once used for clothes worn by the Roman Emperors. Tyrian purple as it was called was extracted from the Mediterranean mollusc Murex brandaris and this molecule contains two bromine atoms and is 6,6'-dibromoindigo.

Even when it appears benign as bromide ions in water, this element can still pose a threat to health. Ozonising drinking water in order to sterilise it converts any bromide to bromate (BrO3-) which is a suspected carcinogen and so must not exceed 10 p.p.b. And some reservoirs in California where this has been exceeded have had to be drained because of it.

Once so beneficial, bromine now appears to cause nothing but trouble. Yet in ways unseen, such as in the pharmaceutical industries, it still continues to be used to provide intermediates in the manufacture of live-saving drugs.

Chris Smith

John Emsley unlocking the secrets of the brown element Bromine. You can find out more about some of John's other favourite elements in a series he has written for the RSC's Education in Chemistry and that's online at Next time on Chemistry in its element Nobel prize winning chemist Kary Mullis explains why a soul of iron is essential.

Kary Mullis

For the human brain, iron is essential yet deadly. Carbon, sulfur, nitrogen, calcium, magnesium, sodium, maybe ten other elements are also involved in life, but none of them have the power of iron to move electrons around, and none of them have the power to totally destroy the whole system. Iron does.

Chris Smith

And you can catch Kary Mullis ironing out the wrinkles in metabolism's most important element on next week's Chemistry in its Element. I'm Chris Smith, thank you for listening, see you next time.


Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by There's more information and other episodes of Chemistry in its element on our website at

(End promo)
  Help text not available for this section currently
  Help Text


Description :
Studying the physical characteristics of the group 7 non-metals known as the halogens
Description :
Demonstrating how the more reactive fluorine displaces the less reactive halogens
Description :
This experiment involves some reactions of the halogens.
Description :
A fast reaction with a burst of flame!
Description :
In this experiment, the similarities and differences in the solubilities of the halides of some Group 1 & 2 metals and silver are investigated using a microscale technique.
Description :
On a microscale students add solutions containing lithium, calcium and silver cations to solutions containing fluoride, chloride, bromide and iodide anions, and record which combinations produce an in...

Terms & Conditions

Images © Murray Robertson 1999-2011
Text © The Royal Society of Chemistry 1999-2011

Welcome to "A Visual Interpretation of The Table of Elements", the most striking version of the periodic table on the web. This Site has been carefully prepared for your visit, and we ask you to honour and agree to the following terms and conditions when using this Site.

Copyright of and ownership in the Images reside with Murray Robertson. The RSC has been granted the sole and exclusive right and licence to produce, publish and further license the Images.

The RSC maintains this Site for your information, education, communication, and personal entertainment. You may browse, download or print out one copy of the material displayed on the Site for your personal, non-commercial, non-public use, but you must retain all copyright and other proprietary notices contained on the materials. You may not further copy, alter, distribute or otherwise use any of the materials from this Site without the advance, written consent of the RSC. The images may not be posted on any website, shared in any disc library, image storage mechanism, network system or similar arrangement. Pornographic, defamatory, libellous, scandalous, fraudulent, immoral, infringing or otherwise unlawful use of the Images is, of course, prohibited.

If you wish to use the Images in a manner not permitted by these terms and conditions please contact the Publishing Services Department by email. If you are in any doubt, please ask.

Commercial use of the Images will be charged at a rate based on the particular use, prices on application. In such cases we would ask you to sign a Visual Elements licence agreement, tailored to the specific use you propose.

The RSC makes no representations whatsoever about the suitability of the information contained in the documents and related graphics published on this Site for any purpose. All such documents and related graphics are provided "as is" without any representation or endorsement made and warranty of any kind, whether expressed or implied, including but not limited to the implied warranties of fitness for a particular purpose, non-infringement, compatibility, security and accuracy.

In no event shall the RSC be liable for any damages including, without limitation, indirect or consequential damages, or any damages whatsoever arising from use or loss of use, data or profits, whether in action of contract, negligence or other tortious action, arising out of or in connection with the use of the material available from this Site. Nor shall the RSC be in any event liable for any damage to your computer equipment or software which may occur on account of your access to or use of the Site, or your downloading of materials, data, text, software, or images from the Site, whether caused by a virus, bug or otherwise.

We hope that you enjoy your visit to this Site. We welcome your feedback.


Visual Elements images and videos
© Murray Robertson 2011.



W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.
J. S. Coursey, D. J. Schwab, J.J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions(version 3.0), 2010, National Institute of Standards and Technology, Gaithersburg, MD, accessed December 2014.
T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.


Uses and properties

John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.
Periodic Table of Videos, accessed December 2014.


Supply risk data

Derived in part from material provided by the British Geological Survey © NERC.


History text

© John Emsley 2012.



Produced by The Naked Scientists.


Periodic Table of Videos

Created by video journalist Brady Haran working with chemists at The University of Nottingham.
  • LearnChemistry
  • Download our free Periodic Table app for mobile phones and tablets now.
  • Google play
  • App Store