Bromine vial in acrylic cube

A vial of liquid Bromine. Credit to Alchemist-hp

Bromine is an element and the only non-metal in the Periodic Table that is a liquid at room temperature. It has 35 for its atomic number; a Bromine atom has 35 protons and electrons, and its mass number is 80; a Bromine atom has 45 neutrons. Its atomic symbol is Br.


Bromine was discovered by the scientists Carl Jacob Löwig[1] and Antoine Balard[2] in 1826;[3] the latter called it a «peculiar substance in sea water.»

Atomic Properties

Bromine is diatomic; any sample of Bromine is made out of a molecule with two Bromine atoms. Bromine reacts with both metals and nonmetals.


Bromine forms many compounds like Sodium Bromide and Potassium Bromide. The most well-known Bromine compound is probably the pH indicator Bromothymol Blue.