Chlorine

Chlorine, 00Cl
A glass container filled with chlorine gas
Chlorine
Pronunciation/ˈklɔːrn, -n/ (KLOR-een, -⁠eyen)
Appearancepale yellow-green gas
Standard atomic weight Ar°(Cl)
[35.44635.457][1]
Chlorine in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
F

Cl

Br
sulfurchlorineargon
Groupgroup 17 (halogens)
Periodperiod 3
Block  p-block
Electron configuration[Ne] 3s2 3p5
Electrons per shell2, 8, 7
Physical properties
Phase at STPgas
Melting point171.6 K ​(−101.5 °C, ​−150.7 °F)
Boiling point239.11 K ​(−34.04 °C, ​−29.27 °F)
Density (at STP)3.2 g/L
when liquid (at b.p.)1.5625 g/cm3[2]
Critical point416.9 K, 7.991 MPa
Heat of fusion(Cl2) 6.406 kJ/mol
Heat of vaporization(Cl2) 20.41 kJ/mol
Molar heat capacity(Cl2)
33.949 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 128 139 153 170 197 239
Atomic properties
Oxidation states−1, 0, +1, +2, +3, +4, +5, +6, +7 (a strongly acidic oxide)
ElectronegativityPauling scale: 3.16
Ionization energies
  • 1st: 1251.2 kJ/mol
  • 2nd: 2298 kJ/mol
  • 3rd: 3822 kJ/mol
  • (more)
Covalent radius102±4 pm
Van der Waals radius175 pm
Color lines in a spectral range
Spectral lines of chlorine
Other properties
Natural occurrenceprimordial
Crystal structureorthorhombic
Orthorhombic crystal structure for chlorine
Speed of sound206 m/s (gas, at 0 °C)
Thermal conductivity8.9×103 W/(m⋅K)
Electrical resistivity>10 Ω⋅m (at 20 °C)
Magnetic orderingdiamagnetic[3]
Molar magnetic susceptibility−40.5·10−6 cm3/mol[4]
CAS Number(Cl2) 7782-50-5
History
Discovery and first isolationCarl Wilhelm Scheele (1774)
Recognized as an element byHumphry Davy (1808)
Isotopes of chlorine
Main isotopes[5] Decay
abun­dance half-life (t1/2) mode pro­duct
35Cl 76% stable
36Cl trace 3.01×105 y β 36Ar
ε 36S
37Cl 24% stable
 Category: Chlorine
| references
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Chlorine gas in a tube

Chlorine (chemical symbol Cl) is a chemical element. Its atomic number (which is the number of protons in it) is 17, and its atomic mass is 35.45. It is part of the 7th column (halogens) on the periodic table of elements.

  1. "Standard Atomic Weights: Chlorine". CIAAW. 2009.
  2. Chlorine, Gas Encyclopaedia, Air Liquide
  3. Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  4. Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  5. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

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