chlorine
Sign in to saveChlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine.
AI overview
Chlorine is a yellow-green gas and chemical element that sits between fluorine and bromine in the periodic table, with properties falling between those two elements. It is extremely reactive and a powerful oxidizing agent, ranking among the highest in the periodic table for electron affinity and electronegativity.
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Article
36 sectionsContents
- History
- Early discoveries
- Isolation
- Later uses
- Properties
- Isotopes
- Chemistry and compounds
- Hydrogen chloride
- Other binary chlorides
- Polychlorine compounds
- Chlorine fluorides
- Chlorine oxides
- Chlorine oxoacids and oxyanions
- Organochlorine compounds
- Occurrence
- Production
- Chloralkali processes
- Non-chloralkali processes
- Applications
- Sanitation, disinfection, and antisepsis
- Combating putrefaction
- Disinfection
- Semmelweis and experiments with antisepsis
- Public sanitation
- Use as a weapon
- World War I
- Middle East
- Biological role
- Hazards
- Chlorine-induced cracking in structural materials
- Chlorine–iron fire
- See also
- Notes
- References
- Bibliography
- External links
Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine.
Chlorine played an important role in the experiments conducted by medieval alchemists, which commonly involved the heating of chloride salts like ammonium chloride (sal ammoniac) and sodium chloride (common salt), producing various chemical substances containing chlorine such as hydrogen chloride, mercury(II) chloride (corrosive sublimate), and . However, the nature of free chlorine gas as a separate substance was only recognised around 1630 by Jan Baptist van Helmont. Carl Wilhelm Scheele wrote a description of chlorine gas in 1774, supposing it to be an oxide of a new element. In 1809, chemists suggested that the gas might be a pure element, and this was confirmed by Sir Humphry Davy in 1810, who named it after the Ancient Greek (, "pale green") because of its colour.