Chlorine gas, represented by the chemical formula Cl2, is a greenish-yellow gas with a strong, pungent odor. It is composed of two chlorine atoms bonded together and is commonly used as a disinfectant in water treatment and swimming pools. Chlorine is a highly reactive element and can form compounds with many other elements. In its elemental form, Cl2 is toxic and can be harmful to humans and the environment. It is important to handle chlorine with care, as exposure can lead to respiratory issues and other health problems. Chlorine is also used in the production of various chemicals, including PVC and bleach.