The chemical element chlorine is a greenish yellow gas with a sharp, disagreeable odor. It belongs to the HALOGENS, a group that includes the elements bromine, fluorine, iodine, and astatine. Its chemical symbol is Cl, atomic number 17, and atomic weight 35.453. Chlorine is about 2.5 times as dense as air and moderately soluble in water, forming a pale yellowish green solution. Chlorine was used in World War I as a poison gas. It is very corrosive to moist tissue and has a very irritating effect on the lungs and mucous membranes of the nose and throat. Inhalation of chlorine gas can cause edema of the lungs and respiratory stoppage.

ALWAYS OPEN CHLORINE CONTAINERS IN WELL VENTILATED AREAS!

Chlorine Contamination (i.e. from other chemicals, organic matter, metals, water) can and will cause gases or explosive results!!

Like all members of the halogen group, chlorine has a strong tendency to gain one electron and become a chloride ion. Chlorine is less active than fluorine but more so than bromine and iodine. It readily reacts with metals to form chlorides, most of which are soluble in water. Chlorine also reacts directly with many nonmetals such as sulfur, phosphorus, and other halogens. Chlorine forms five different oxides: dichloride monoxide; chlorine monoxide; chlorine dioxide; chlorine hexoxide; and chlorine heptoxide. The oxidizing ability of chloride of lime enables it to destroy bacteria; therefore large quantities are used to treat municipal water systems. This chemical is also used in swimming pools, for treating sewage, and making plastics.