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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

Appearance and physical state

Bromine is a dense, dark-red, fuming, highly corrosive and lacrimatory liquid at ordinary pressures and temperatures. The vapour is amber coloured and the solid is almost black. Bromine has a strong, pungent odour.

Melting point/freezing point

The melting point of bromine is -7.25 °C.

Boiling point

The boiling point of bromine is between 58.8 and 59.7 °C.


The density of liquid bromine ranged from 3.0879 at 30 °C to 3.1396 at 15 °C.

Vapour pressure

The measured vapour pressure was reported as 2.8E04 Pa (212 mm Hg) at 25ºC.

Partition coefficient

Bromine is an inorganic substance. A calculated estimate of the log Pow is 1.03.

Water solubility

Bromine is very soluble in water, 33.6 g/L at 25 ºC.

Solubility and stability in organic solvents

Bromine is soluble to infinitely soluble in many organic solvents (carbon tetrachloride, chloroform, methylene chloride, carbon disulfide, alkyl bromides, ether, methanol, 48% hydrobromic acid, concentrated HCl, aqueous metallic halides, benzene, gasoline, ethanol, and hydrogen sulfide.

Stability in organic substances is not required for an inorganic substance.

Surface tension

Based on the ECHA integrated testing strategy for surface tension, an experimental determination for this endpoint is not required. Bromine does not contain structural alerts (e.g., -SO3-, -SO4-, -[OCH2CH2]n, -N+[CH3]3) nor does it cause foaming; therefore, no testing is required.

Flash point

Determination of a flash point is not required for inorganic substances.


Bromine is flammable in liquid or vapor form in the presence of reducing agents.


Bromine is not combustible but is flammable in conjunction with antimony, boron, cesium acetylene carbide, chlorotrifluoroethylene, copper hydride, cuprous acetylide, fluorine, germanium, lithium carbide, magnesium phosphide, phosphine, phosphorus, phosphorus oxide, phosphorus trioxide, rubidium acetylene carbide, rubidium carbide, and sodium acetylene carbide, strontium phosphide and zirconium dicarbide.


Bromine is an inorganic substance that does not contain a chemical group associated with explosivity. In addition an explosive substance or mixture is a solid or liquid substance or mixture of substances which is in itself capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed as to cause damage to the surroundings. Bromine is an oxidizing agent and is known to react with other chemical agents in an explosive manner, but this property does not conform with the requirement for classification as an explosive substance.

Oxidising properties

Bromine is a strong oxidising agent. It reacts with a variety substances in an explosive manner (Bretherick, 1990; Quincy, 2002)

Oxidation reduction potential

Elemental Bromine is a strong oxidizing substance with a normal redox potential of 1.07 v at 25 ºC. The normal redox potential of elemental chlorine is 1.4 v.

Dissociation constant

In water, bromine rapidly hydrolyses to form hypobromous acid (HOBr):

Br2+ H2O → HOBr + H++ Br-  (hydrolysis constant 5.8 x 10-9at 25 ºC).

In pure aqueous solutions, the species present are molecular bromine (Br2),hypobromous acid, and the hypobromite ion resulting from the dissociation of hypobromous acid. 

HOBr = OBr-+ H+