Chlorine

Carl Wilhelm Scheele, discoverer of chlorine
Chlorine, liquefied under a pressure of 7.4 bar at room temperature, displayed in a quartz ampule embedded in acrylic glass.
Solid chlorine at −150 °C
Structure of solid deuterium chloride, with D···Cl hydrogen bonds
Hydrated nickel(II) chloride, NiCl2(H2O)6.
Yellow chlorine dioxide (ClO2) gas above a solution containing chlorine dioxide.
Structure of dichlorine heptoxide, Cl2O7, the most stable of the chlorine oxides
Suggested mechanism for the chlorination of a carboxylic acid by phosphorus pentachloride to form an acyl chloride
Liquid chlorine analysis
Membrane cell process for chloralkali production
Ignaz Semmelweis
Liquid Pool Chlorine
Chlorine "attack" on an acetal resin plumbing joint resulting from a fractured acetal joint in a water supply system which started at an injection molding defect in the joint and slowly grew until the part failed; the fracture surface shows iron and calcium salts that were deposited in the leaking joint from the water supply before failure and are the indirect result of the chlorine attack

Chemical element with the symbol Cl and atomic number 17.

- Chlorine
Carl Wilhelm Scheele, discoverer of chlorine

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Hydrochloric acid fumes turning pH paper red showing that the fumes are acidic

Hydrogen chloride

Hydrogen halide.

Hydrogen halide.

Hydrochloric acid fumes turning pH paper red showing that the fumes are acidic
Infrared (IR) absorption spectrum
One doublet in the IR spectrum resulting from the isotopic composition of chlorine

Hydrogen chloride is a diatomic molecule, consisting of a hydrogen atom H and a chlorine atom Cl connected by a polar covalent bond.

The structure of sodium chloride, revealing the tendency of chloride ions (green spheres) to link to several cations.

Chloride

Anion Cl−.

Anion Cl−.

The structure of sodium chloride, revealing the tendency of chloride ions (green spheres) to link to several cations.
Basic membrane cell used in the electrolysis of brine. At the anode (A), chloride (Cl−) is oxidized to chlorine. The ion-selective membrane (B) allows the counterion Na+ to freely flow across, but prevents anions such as hydroxide (OH−) and chloride from diffusing across. At the cathode (C), water is reduced to hydroxide and hydrogen gas.

It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents.

Phase diagram of water–NaCl mixture

Sodium chloride

Ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions.

Ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions.

Phase diagram of water–NaCl mixture
Mounds of road salt for use in winter
A class-D fire extinguisher for various metals
Sodium chloride crystal under microscope.
NaCl octahedra. The yellow stipples represent the electrostatic force between the ions of opposite charge
Modern rock salt mine near Mount Morris, New York, United States
Jordanian and Israeli salt evaporation ponds at the south end of the Dead Sea.
Mounds of salt, Salar de Uyuni, Bolivia.

Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses.

The international pictogram for oxidizing chemicals.

Oxidizing agent

Substance in a redox chemical reaction that gains or "accepts"/"receives" an electron from a (called the, , or ).

Substance in a redox chemical reaction that gains or "accepts"/"receives" an electron from a (called the, , or ).

The international pictogram for oxidizing chemicals.
Dangerous goods label for oxidizing agents
Tetracyanoquinodimethane is an organic electron-acceptor.

Fluorine (F2), chlorine (Cl2), and other halogens

Sir Humphry Davy, Bt by Thomas Phillips

Humphry Davy

British chemist and inventor from Cornwall who invented the Davy lamp and a very early form of arc lamp.

British chemist and inventor from Cornwall who invented the Davy lamp and a very early form of arc lamp.

Sir Humphry Davy, Bt by Thomas Phillips
James Watt in 1792 by Carl Frederik von Breda
Sir Humphry Davy's Researches chemical and philosophical: chiefly concerning nitrous oxide (1800), pp. 556 and 557 (right), outlining potential anaesthetic properties of nitrous oxide in relieving pain during surgery
1802 satirical cartoon by James Gillray showing a Royal Institution lecture on pneumatics, with Davy holding the bellows and Count Rumford looking on at extreme right. Dr Thomas Garnett is the lecturer, holding the victim's nose.
Sodium metal, about 10 g, under oil
A voltaic pile
Magnesium metal crystals
Sir Humphry Davy by Thomas Lawrence
A diamond crystal in its matrix
The Davy lamp
Statue of Davy in Penzance, Cornwall, holding his safety lamp
Michael Faraday, portrait by Thomas Phillips c. 1841–1842
Davy's grave at Cimetière Plainpalais in Geneva

He is also remembered for isolating, by using electricity, several elements for the first time: potassium and sodium in 1807 and calcium, strontium, barium, magnesium and boron the following year, as well as for discovering the elemental nature of chlorine and iodine.

Carl Scheele

Carl Wilhelm Scheele

Swedish German pharmaceutical chemist.

Swedish German pharmaceutical chemist.

Carl Scheele
Engraving on the title page of Scheele's Chemical Treatise on Air and Fire (1777) (d. Königl. Schwed. Acad. d. Wissenschaft Mitgliedes, Chemische Abhandlung von der Luft und dem Feuer)
Pyrolusite or MnO2.
Chlorine gas.
Statue of Scheele in Köping, Sweden.
Mémoires de chymie, 1785, French translation by Mme. Claudine Picardet
Early history of chlorine, 1944

Scheele discovered oxygen (although Joseph Priestley published his findings first), and identified molybdenum, tungsten, barium, hydrogen, and chlorine, among others.

A pound coin (density ~7.6 g/cm3) floats on mercury due to the combination of the buoyant force and surface tension.

Mercury(II) chloride

A pound coin (density ~7.6 g/cm3) floats on mercury due to the combination of the buoyant force and surface tension.

Mercury(II) chloride (or mercury bichloride, mercury dichloride), historically also known as sulema or corrosive sublimate, is the inorganic chemical compound of mercury and chlorine with the formula HgCl2.

Clorox brand bleach

Bleach

Generic name for any chemical product that is used industrially or domestically to remove color from a fabric or fiber or to clean or to remove stains in a process called bleaching.

Generic name for any chemical product that is used industrially or domestically to remove color from a fabric or fiber or to clean or to remove stains in a process called bleaching.

Clorox brand bleach
Early method of bleaching cotton and linen goods on lawns

Chlorine, a powerful oxidizer, is the active agent in many household bleaches.

Disinfection of a floor using disinfectant liquid applied using a mop.

Disinfectant

Chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces.

Chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces.

Disinfection of a floor using disinfectant liquid applied using a mop.
Levels of resistance of microbes to disinfectants.
Disinfectants are used to rapidly kill bacteria. They kill off the bacteria by causing the proteins to become damaged and the outer layers of the bacteria cell to rupture. The DNA material subsequently leaks out.
Automatic hand sanitizer in Tomaszów Mazowiecki, Poland

In wastewater treatment, a disinfection step with chlorine, ultra-violet (UV) radiation or ozonation can be included as tertiary treatment to remove pathogens from wastewater, for example if it is to be discharged to a river or the sea where there body contact immersion recreations is practiced (Europe) or reused to irrigate golf courses (US).

Salt deposits beside the Dead Sea

Salt

Mineral composed primarily of sodium chloride , a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite.

Mineral composed primarily of sodium chloride , a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite.

Salt deposits beside the Dead Sea
Halite (rock salt) from the Wieliczka salt mine, Małopolskie, Poland
Bolivian rose salt from Andes
Loading sea salt at an evaporation pond in Walvis Bay, Namibia; halophile organisms give it a red colour
Salt production in Halle, Saxony-Anhalt (1670)
Ponds near Maras, Peru, fed from a mineral spring and used for salt production since pre-Inca times.
SEM image of a grain of table salt
Comparison of table salt with kitchen salt. Shows a typical salt shaker and salt bowl with salt spread before each on a black background.
Irregular crystals of sea salt
Himalayan salt is halite with a distinct pink color
Two men with stacks of rock salt in Bamyan, Afghanistan
Sea salt evaporation pond at Walvis Bay. Halophile organisms impart a red colour
Bread and salt at a Russian wedding ceremony

Its major industrial products are caustic soda and chlorine; salt is used in many industrial processes including the manufacture of polyvinyl chloride, plastics, paper pulp and many other products.