(Gr. chloros: greenish yellow) Discovered in 1774 by Scheele, who thought it contained oxygen. Chlorine was named in 1810 by Davy, who insisted it was an element.

In nature it is found in the combined state only, chiefly with sodium as common salt (NaCl), carnallite, and sylvite.

It is a member of the halogen (salt-forming) group of elements and is obtained from chlorides by the action of oxidizing agents and more often by electrolysis; it is a greenish-yellow gas, combining directly with nearly all elements. At 10oC one volume of water dissolves 3.10 volumes of chlorine, at 30oC only 1.77 volumes. 
A Periodic Table of the Elements at Los Alamos National Laboratory