Facts About Chlorine

Credit: Greg Robson/Creative Commons, Andrei Marincas | Shutterstock
Atomic Number: 17
Atomic Symbol: Cl
Atomic Weight: 35.453
Melting Point: -150.7 F (-101.5 C)
Boiling Point: -29.27 F (-34.04 C)

Word origin: The word chlorine comes from the Greek word chloro (greenish yellow).

Discovery: Chlorine was discovered in 1774 by Carl Wilhelm Scheele, who believed it contained oxygen. In 1810, Humphry Davy named it as an element.

Properties of chlorine

Chlorine is a member of the halogen (salt-forming) group of elements. It is a greenish-yellow gas that is capable of combining directly with nearly all elements. [See Periodic Table of the Elements]

Chlorine is a respiratory irritant. Its gas irritates mucus membranes and the liquid burns the skin. Small amounts of chlorine (as little as 3.5 ppm) can be smelled, and inhaling 1,000 ppm for a few deep breaths can be fatal. For this reason, chlorine was used as a war gas in 1915. Today, those working with chlorine are advised not to be exposed to more than 0.5 ppm in an eight-hour shift of a 40-hour work week.

Sources of chlorine

In nature, chlorine is only found in a combined state. Usually it is combined with sodium as common salt, carnallite and sylvite.

Chlorine can be obtained from chlorides through oxidizing agents and more often by electrolysis.

Chlorine is a respiratory irritant. Inhaling 1,000 ppm for a few deep breaths can be fatal.
Credit: Pi-Lens | Shutterstock

Uses of chlorine

Chlorine dioxide is widely used in everyday products. Around the world, humans use it for producing safe drinking water and clean swimming pools. Today, even the smallest water supplies are usually chlorinated.

Most produced chlorine is used in the manufacture of chlorinated compounds for sanitation, pulp bleaching, disinfectants and textile processing. Some of the products it is found in are:

  • Paper products
  • Dyestuffs
  • Textiles
  • Petroleum products
  • Medicines
  • Antiseptics
  • Insecticides
  • Food
  • Solvents
  • Paints
  • Plastics

Chlorine is also used to manufacture chlorates, chloroform, carbon tetrachloride, and in the extraction of bromine.

Organic chemistry processes often require chlorine. It is commonly used as an oxidizing agent and as a substitution for hydrogen. When substituted, it can bring together many desired properties in an organic compound. For example, chlorine is used in the creation of synthetic rubber.

(Source: Los Alamos National Laboratory)

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