| Chlorine - Cl
CAS: 7782-50-5 Description: Yellow-green gas Classification: Halogen Date of Discovery: 1774 Discoverer: Carl Wilhelm Scheele Name Origin: Greek khlôros "greenish-yellow" |
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Atomic Number: 17
Number of Neutrons: 18 Atomic Mass: 35.4527(9) amu Melting Point: -101.5 °C Boiling Point: -34.04 °C Density (293 K): 3.214 g/cm3 1.56 g/cm3 (liquid, -33.6 °C) Atomic volume: 22.7 cm3/mol Electrical resistivity: Thermal conductivity: 0.000089 W/cmK Enthalpy of atomization: 121.75 kJ/mol Enthalpy of vaporization: 10.20 kJ/mol Enthalpy of fusion: 3.203 kJ/mol Specific heat capacity: 0.48 J/gK |
Energy levels: 2-8-7
Electron configuration: [Ne]3s23p5 Crystal Structure: Orthorhombic Atomic radius: 0.97 Å Covalent radius: 0.99 Å Oxidation States: -1, +1, +3, +5, +7 Electronegativity, Pauling: 3.16 Electron affinity: 3.61269 eV First ionization energy: 12.967 eV 2nd ionization energy: 23.81 eV 3rd ionization energy: 39.611 eV Polarizability: 2.18 10-24cm3 |
| Isotope | Natural Abundance | Atomic Mass | Half-life | Decay Mode | Spin |
| 31Cl | 30.99242 | 0.15 s |  +, p |
3/2+ | |
| 32Cl | 31.98569 | 297 ms | + |
1+ | |
| 33Cl | 32.977452 | 2.511 s | + |
3/2+ | |
| 34mCl | - |
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| 34Cl | 33.9737630 | 32.2 m | +; IT |
3+ | |
| 35Cl | 75.77(7) | 34.96885271 | Stable | 3/2+ | |
| 36Cl | 35.9683069 | 3.01 x 105y | - |
0+ | |
| 37Cl | 24.23(7) | 36.9659026 | Stable | 3/2+ | |
| 38mCl | 0.715 s | IT | 5- | ||
| 38Cl | 37.9680106 | 3.72 m | - |
2- | |
| 39Cl | 38.968009 | 55.6 m | - |
3/2+ | |
| 40Cl | 39.97042 | 1.38 m | - |
2- | |
| 41Cl | 40.9707 | 34 s | - |
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| 42Cl | 41.9732 | 6.8 s | - |
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| 43Cl | 42.9742 | 3.3 s | - |
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| 44Cl | 43.9785 | - |
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| 45Cl | 44.980 | 0.41 | -, n |
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| 46Cl | 45.984 | 0.20 | -, n |
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| 47Cl | 46.988 | -, n |
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Discovered in 1774 by Scheele, who thought it contained oxygen; named in 1810 by Davy, who insisted it was an element. In nature it is found in the combined state only,
chiefly with sodium as common salt (NaCl), carnallite (KMgCl3 · 6H2O), and sylvite (KCl). It is a member of the halogen (salt-forming) group of elements and is obtained from chlorides by the action of oxidizing agents and more often by electrolysis; it is a greenish-yellow
gas, combining directly with nearly all elements. At 10 °C one volume of water dissolves 3.10 volumes of chlorine, at 30 °C only 1.77 volumes. Chlorine is widely used in making many everyday products. It is used for producing safe drinking water the world over. Even the smallest water supplies are now usually chlorinated. It is also
extensively used in the production of paper products, dyestuffs, textiles, petroleum products, medicines, antiseptics, insecticides, foodstuffs, solvents, paints, plastics, and many other consumer products. Most of the chlorine produced is used in the manufacture of chlorinated compounds for sanitation, pulp bleaching, disinfectants, and textile processing. Further use is in the manufacture of chlorates, chloroform, carbon tetrachloride, and in the extraction of bromine. Organic chemistry demands much from chlorine, both as an oxidizing agent and in substitution, since it often brings desired properties in an organic compound when substituted for hydrogen, as in one form of
synthetic rubber. Chlorine is a respiratory irritant. The gas irritates the mucous membranes and the liquid burns the skin. As little as 3.5 ppm can be detected as an odor, and 1000 ppm is likely to be fatal after a few deep breaths. It was used as a war gas in 1915. Natural chlorine contains two isotopes. Sixteen other isotopes and isomers are known.
LINKS: Chlorine Chemistry Council The Chlorine Institute, Inc. Davy on Chlorine Facts About Chlorine, The Material Used to Make Vinyl OSHA Chemical Sampling Information Potential Health Hazards from Chlorine Return
Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998. |
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