The 17th element of the periodic table has a dark history – it’s a relic of the first world war that reports say has made a reappearance in the conflict in Syria
On 2 August this year I noticed a small piece on the BBC news website about a gas attack in Syria. Accounts of the appalling situation in Syria and new devastating attacks seem to be almost a daily feature in the news. What I found especially depressing about the short item that made the news that day, was the alleged use of chlorine gas. Allegations of chlorine gas attacks have appeared again in the news on 11 August, this time resulting in the deaths of one woman and two children as well as a formal investigation by the UN.
Chlorine, the 17th element in the periodic table, is an industrially important chemical. Among other applications it is used in the dying industry and forms the basis for many household bleaches. But chlorine is perhaps most well known as an addition to swimming pools where, in small quantities, it reacts with the water to form hypochlorous acid that kills bacteria and prevents the growth of algae, resulting in safe, sanitary conditions for swimming.