Bromine is a chemical element in the periodic table that has many unusual properties: For example, it is one of only two elements that are liquid at room temperature.

It was first isolated from seaweed in 1826 by the French chemist Antoine-Jérôme Balard. However, industrial production did not begin until 1860, when Joseph Louis Gay-Lussac suggested the name (from the Greek: "goat smell of animals") for bromine, as it has a pungent odor.

As it is toxic and corrosive, bromine vapors should never be inhaled and contact with the skin should be avoided.

Bromine is a chemical element with the element symbol Br and atomic number 35. In the periodic table, it is in the 7th main group or the 17th IUPAC group and thus belongs to the halogens together with fluorine, chlorine, iodine, astatine and tenness. Under standard conditions (temperature = 0 °C and pressure = 1 atm), elemental bromine exists in liquid form in the form of the diatomic molecule Br2. Bromine and mercury are the only natural elements that are liquid under standard conditions.

In nature, bromine does not occur as an element, but only in various compounds. The most important compounds are the bromides, in which bromine occurs in the form of the anion Br-. The best-known bromides are sodium bromide and potassium bromide. These compounds have a number of biological functions and are also used as disinfectants, bleaching agents and antiseptics.

Bromine, a toxic and corrosive element, was first extracted from seawater in 1826 by the French chemist Antoine-Jérôme Balard, who recognized it as a previously unknown substance.

Balard's discovery was made two years before the unknowing production of elemental bromine by the German chemist Justus von Liebig in 1824.

Liebig had been commissioned to analyze the salt brine of Salzhausen, as the town was planning a health resort. While analyzing these brines, he found a new substance which he interpreted as iodine chloride. 13 years later, he admitted that his careless analysis had deprived him of the discovery of a new element. He wrote about it: "I know a chemist who, when he was in Kreuznach, examined the mother liquors of the salt works." He then went on to describe his misadventure and concluded with the words: "Since then he has not put forward any theories unless they have been supported and confirmed by undoubted experiments; and I can report that he has not done badly."

Karl Löwig also worked on bromine, but was overtaken by Balard when it was published.

Bromine is one of the elements that make up the earth's crust. It is also a naturally occurring element found in seawater in the form of bromide ions. Bromine also occurs in natural salts such as rock salt, potassium salt and brine wells. The largest deposits are found dissolved in seawater.

Bromine can also occur in the atmosphere as molecular bromine and bromine oxide. These molecules are transported over long distances and can have a significant impact on ozone chemistry in the atmosphere. During the polar spring, high concentrations (>10 ppt) of bromine regularly destroy almost all tropospheric ozone. These events can also be observed by satellites using the DOAS method. In tropical regions with high bioactivity, strong emissions of halocarbons have been observed, which can ultimately contribute to BrO formation and ozone destruction by photolysis.

Trace amounts of bromine are vital for animals. Bromide acts as a cofactor in a metabolic reaction that is necessary for the formation of the collagen IV matrix in connective tissue.