Chlorine is a nonmetal in the halogen group. Under standard conditions, chlorine is a yellow-green gas at room temperature, as it has a boiling point of -29.27 degrees Fahrenheit. Like all halogens, chlorine is highly reactive, and large amounts can be dangerous or even lethal to human beings.
Chlorine is commonly used as an antiseptic and a disinfectant. It is normally used to make drinking water safe, to treat swimming pools and in the manufacturing process of several household items, such as paper and textiles. Some familiar chlorine compounds include sodium chloride, usually referred to as table salt, and hydrogen chloride.