Chlorine is a greenish-yellow gas or clear amber liquid (under pressure) with a pungent suffocating odour. It will not burn. Chlorine is a COMPRESSED GAS and a STRONG OXIDIZER. If chlorine contacts combustible materials fire or explosion may result. Chlorine reacts violently or explosively with many substances. It reacts with water to form corrosive hydrochloric and hypochlorous acids. Chlorine is a confined space hazard. Chlorine is VERY TOXIC. It may be fatal if inhaled. It is extremely irritating to the respiratory tract and causes lung injury--effects may be delayed. Chlorine is CORROSIVE to the eyes and skin. Liquefied gas can cause frostbite and corrosive injury to the eyes and skin. Burns and permanent damage, including blindness may result.

The major uses of chlorine are in the manufacture of chlorinated organic chemicals (such as vinyl chloride monomer, carbon tetrachloride, perchlorethylene, 1,1,1-trichloroethane, chlorobenzenes, chloroprene and epichlorohydrin), organic chemicals (such as propylene oxide and glycols) and chlorinated inorganic chemicals (such as sodium hypochlorite, hydrochloric acid, hypochlorous acid, sulfur chlorides, phosphorous chlorides, titanium chlorides and aluminum chloride). It is also widely used as a bleaching agent in the manufacture of pulp and paper; in bleaching textiles and fabrics; in the manufacture of pesticides, herbicides, refrigerants, propellants, household and commercial bleaches, detergents for automatic dishwashers, antifreeze, antiknock compounds, plastics, synthetic rubbers, adhesives and pharmaceuticals; for drinking and swimming water purification; sanitation of industrial and sewage wastes; and in the degassing of aluminum metal.

Chlorine is shipped in steel cylinders as a compressed liquefied gas under its own vapour pressure of 598 kPa (86.8 psig or 5.9 atm.) at 21.1 deg C. It is available in a number of grades having a purity of at least 99.5 wt%. Contaminants are mainly carbon dioxide, nitrogen, oxygen and water, but may include traces of chlorinated hydrocarbons, such as hexachloroethane and hexachlorobenzene, inorganic salts such as ferric chloride, bromine or iodine.

Chlorine is also known as liquefied chlorine gas, molecular chlorine, and as chlore in French.

Its CAS Registry Number is 7782-50-5. This number is assigned by the Chemical Abstracts Service (CAS) in the United States and is used as a unique identifier number world-wide.