{"id":140,"date":"2020-04-09T09:29:30","date_gmt":"2020-04-09T09:29:30","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=140"},"modified":"2023-08-16T08:16:40","modified_gmt":"2023-08-16T08:16:40","slug":"chlorine","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/chlorine\/","title":{"rendered":"Chlorine (Cl)"},"content":{"rendered":"\n

Chlorine is a chemical element with an atomic number of 17 in the periodic table of elements. It\u2019s the twentieth most abundant element found in Earth\u2019s crust, amounting to 130 ppm or 0.01 percent. Being a member of the halogen<\/a> family of periodic table elements<\/a>, chlorine is a highly reactive chemical substance with seven valence electrons in its outer shell.<\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Chlorine<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>Cl<\/td><\/tr>
Name<\/td>Chlorine<\/td><\/tr>
Atomic number<\/td>17<\/td><\/tr>
Atomic weight<\/td>35.4527 g.mol-1<\/td><\/tr>
Group<\/td>Halogen<\/a><\/td><\/tr>
Period<\/td>3<\/td><\/tr>
Color<\/td>Pale greenish-yellow gas at room temperature \/ Clear, amber-colored liquid under applied pressure or at temperatures below -30\u00b0F (-34\u00b0C)<\/td><\/tr>
Physical state<\/td>Gas \/ Liquid \/ Solid<\/td><\/tr>
Crystal Structure<\/td>Orthorhombic<\/td><\/tr>
Electronegativity<\/td>3.16<\/td><\/tr>
Density<\/td>0.003214 g\/cm\u00b3<\/td><\/tr>
Melting point<\/td>172.17 \u00b0C<\/td><\/tr>
Boiling point<\/td>239.1 \u00b0C<\/td><\/tr>
Ionic radius<\/td>1.81 (-1) \u00c5<\/td><\/tr>
Isotopes<\/td>24<\/td><\/tr>
Most characteristic isotope<\/td>35Cl, 36Cl, 37Cl<\/td><\/tr>
Electronic shell<\/td>[Ne] 3s2 3p5<\/td><\/tr>
The energy of the first ionization<\/td>1255.7 kJ.mol-1<\/td><\/tr>
Discoverer<\/td>Carl Wilhelm Scheele<\/td><\/tr>
Year<\/td>1774<\/td><\/tr>
Location<\/td>Sweden<\/td><\/tr>
Pronunciation<\/td>KLOR-een<\/td><\/tr>
Oxydation States<\/td>(\u00b11),3,5,7<\/td><\/tr>
Uses<\/td>Used in water purification, bleaches, acids and many other compounds such as chlorofluorocarbons (CFC)<\/td><\/tr>
Description<\/td>Colorless, odorless, tasteless noble gas<\/a>. It is the third most abundant element in the earth’s atmosphere and makes up about 1%.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
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Diatomic in nature (occurring as Cl<\/span>2<\/span>), this yellow-green gaseous element with a pungent, irritating odor carries the symbol Cl and the atomic number 17 in the periodic table of elements. Having an atomic mass of 35.45 g.mol -1 and electron configuration [Ne] 3s2 3p5, chlorine is a chemical element that is heavier than air.<\/span><\/p>\n\n\n\n

It changes from a gaseous aggregate state into a liquid under pressure. The solid form of chlorine occurs as calcium <\/a>hypochlorite [Ca(OCl)2].<\/span><\/p>\n\n\n\n

Furthermore, chlorine reaches its boiling point at -34.6 \u00b0C, while the melting point of this gas is achieved at -101 \u00b0C. This member of the halogen family of elements in the periodic table has an electronegativity of 3.16 according to Pauling, whereas the atomic radius according to van der Waals is 0.127 nm.   <\/span><\/p>\n\n\n\n

Despite being a non-flammable gas in its elemental form, chlorine reacts in a volatile and explosive manner due to its combustion-enhancing properties. Namely, when chlorine is compounded with bases, turpentine, ammonia, fuel gas, hydrogen<\/a>, fluorine<\/a>, and organic compounds, it poses a potential risk of fire or explosion. <\/span><\/p>\n\n\n\n

Highly reactive with water (H2O), chlorine also becomes very corrosive when combined with H2O molecules. Apart from adopting highly corrosive properties, chlorine makes for a strong acid and an oxidizer in the presence of water molecules that readily attacks rubber, plastic, and various metals.\u00a0<\/span><\/p>\n\n\n\n

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How Was Chlorine Discovered?<\/span><\/h2>\n\n\n\n

Traces of the chlorine compounds that are nowadays extensively used in the industries (pentachlorophenol, polychloropyrols, polychlorinated biphenyls (PCB), and tetrachlorodibenzodioxins (TCDD)) have been found in rock sediments as old as 8,000 years. And, like almost all great inventions and discoveries of the modern times, chlorine was discovered after an oversight.<\/span><\/p>\n\n\n\n

Namely, in 1774, the Swedish pharmacist Carl Wilhelm Scheele (1942 – 1786) attempted an experiment by causing a reaction between hydrochloric acid with manganese <\/a>dioxide. In an instant, a greenish-yellow gas was released from the chemical mixture. However, Scheele didn\u2019t realize that he had just discovered a new chemical element. <\/span><\/p>\n\n\n\n

He firmly believed that what he had in front of him was a compound of oxygen<\/a>, which he called \u2018a dephlogisticated marine acid\u2019.\u00a0<\/span><\/p>\n\n\n\n

Several decades later, in 1810 to be more precise, the English chemist Sir Humphry Davy (1778 – 1829) gave more attention to this compound, and by conducting his experiments on what was believed to be dephlogisticated marine acid, Sir Davy succeeded in affirming chlorine as a new chemical element by proving that there is no oxygen in the compound. The English chemist also managed to determine the properties of the newly established chemical element.\u00a0<\/span><\/p>\n\n\n\n

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How Did Chlorine Get Its Name?<\/span><\/h2>\n\n\n\n

The name of the chemical element chlorine comes from the Greek word \u201ckhloros\u201d that literally depicts the green color of chlorine\u2019s pure elemental form. This chemical element was named in 1810 by Sir Humphry Davy.\u00a0\u00a0<\/span><\/p>\n\n\n\n

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Where Can You Find Chlorine?<\/span><\/h2>\n\n\n\n

Chlorine belongs to the group of chemical elements that can be found in their elemental form in nature, counting approximately a hundred of them. These elements are considered to be the basic building blocks of our planet, as well as the life on it.\u00a0\u00a0<\/span><\/p>\n\n\n\n

This chemical element can be naturally found in inorganic chlorinated substances (such as sodium <\/a>chloride, or table salt), as well as in organochlorines. Chlorine is released in the atmosphere from the ocean algae in a form of methyl chloride. This yellow-green gas is also released by volcanoes, forest fires, and some plants. Seawater and the Sun also contain certain quantities of chlorine in its elemental form.\u00a0<\/span><\/p>\n\n\n\n

Today, chlorine is mostly obtained by electrolysis of sodium chloride solutions. This chemical element not only has a versatile use in everyday life, but it also has an efficient process of production. Namely, sodium hydroxide and hydrogen as by-products of the chlorine production process, have an equally wide application as chlorine in various industrial processes and in everyday life.\u00a0<\/span><\/p>\n\n\n\n

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Chlorine in Everyday Life<\/span><\/h2>\n\n\n\n

Due to the strong bactericidal properties, chlorine gas and its compounds are frequently used in everyday life as bleach, disinfectants, table salts, cleaning products, or insecticides. This gaseous chemical substance also finds extensive application in the industry. It has a wide variety of applications:<\/span><\/p>\n\n\n\n