Bromine

 Atomic Number:

35

 Melting Point: -7.2 ºC
Atomic Symbol: Br Boiling Point:  58.8 ºC
Atomic Weight: 79.904 amu Density: 3119 kg/m 3
Atomic Radius:

115 pm

 Oxidation States: 5, 1, -1
Covalent Radius: 114 pm Electron Configuration: [Ar]4s23d104p5
van der Waals Radius:

185 pm

 State of Matter: solid (at STP)

History

(Gr. bromos: stench) Discovered by Balard at salt marshes of Montpellier in 1826, but not prepared in quantity until 1860.

Properties

Bromine is the only  nonmetallic liquid 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.

Sources

A member of the halogen group, bromine is obtained from natural brines from wells in Michigan and Arkansas. Some bromine is extracted today from seawater, which contains only about 85 ppm.

Uses

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 used in making fumigants, flameproofing agents, water purification compounds, dyes, medicines, sanitizers, inorganic bromides for photography, etc. Organic bromides are also important.

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

Isotopes

Bromine has several isotopes, with the most significant ranging in half lifes from a few minutes to several hours.

Hazards

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.

Accordingly, one should always wear safety goggles and ensure adequate ventilation when handling bromine.