Chlorine

**Semantic type:** Element, Ion, or Isotope|Hazardous or Poisonous Substance

**Definition:** A naturally occurring halogen element with atomic symbol Cl, atomic number 17, and atomic mass 35.453. Chlorine is used in many industrial processes, as well as in pesticides, pharmaceuticals, and water purification. It is characterized as a greenish-yellow gas with a pungent odor, and exposure occurs by inhalation, ingestion, or contact.

**Synonyms:** - CHLORINE - Cl - chlorine