The History of Halogen Discoveries

Chlorine was also discovered by Scheele in the form of deflogisticated muric acid and he did not regard it as a simple substance though he observed precisely the evolution of a free halogen. This fact makes the accepted discovery date for chlorine (1774) better substantiated than that for fluorine for which the simple substance had yet to be extracted. The decisive event in the history of chlorine was the establishment of its elementary nature in 1810 by Davy. 

After the usual sections on the history of the discoveries of and the application of the network to the halogens, special sections on (1) the oxoacids and their salts and (2) the interhalogens follow. The section on reactions and compounds of practical importance comes next and finally the selected topic in depth, which concerns the threat posed by chlorofluorocarbons to the ozone layer. 

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