(From the Greek bromos, "stench") A chemical element, one of the halogens, usually in the form of a reddish-brown, corrosive liquid, that volatilizes to form a vapor that has an unpleasant odor and is very irritating to mucous membranes. It is used in making dyes, in photography, and, in the form of certain compounds, in antiknock motor fuel.

Symbol: Br
Atomic number: 35
Atomic weight: 79.904
Density (at room temperature and pressure): 3.12 g/cc
Melting point: -7.2°C
Boiling point: 58.8°C
Valence: -1, +1, +5
Ground state electron configuration: [Ar]3d104s24p5