Element 35 in our International Year of the Periodic Table series is bromine. One of only two elements in the periodic table that are liquids at room temperature, its compounds are used as flame retardants and were historically used in dyes.

Bromine is the only non-metal which is a liquid at room temperature. It’s a volatile red-brown liquid with a strong, sharp odour. This lends the element its name: bromine comes from the Greek ‘bromos’ meaning ‘stench’. The only other element which is a liquid at room temperature is the metal, mercury.

Some brominated compounds are used as flame retardants. These can be found in electronics, plastics, clothes, and upholstery. In 2011, brominated flame retardants accounted for almost 20% of the total market for flame retardants, though their use has decreased in some applications due to health concerns.

Bromine is also found as part of the natural dye, Tyrian purple, used in ancient times. It is extracted from species of sea snails – with tens of thousands of them needed to produce significant amounts. Perhaps unsurprisingly, this made it prohibitively expensive for all except those of high status and royalty.

Remember, you can keep track of all of the previous entries in this series on the site here, or on the Royal Society of Chemistry’s dedicated page.