Chlorine Elemental Symbol

French German Italian Portuguese Spanish Swedish
Le chlore Chlor Cloro Cloro Cloro Klor

Chlorine Element SymbolChlorine is a Block P, Group 17, Period 3 element.. Its electron configuration is [Ne]3s23p5. The chlorine atom has a covalent radius of 102±4 pm and its Van der Waals radius is 175 pm. In its elemental form, CAS 7440-44-0, chlorine is a yellow-green gas. Chlorine is the second lightest halogen after fluorine. it has the third highest electronegativity and the highest electron affinity of all the elements making it a strong oxidizing agent. It is rarely found by itself in nature. Chlorine was discovered and first isolated by Carl Wilhelm Scheele in 1774. It was first recognized as an element by Humphry Davy in 1808.

Chlorine information, including technical data, safety data and its high purity properties, research, applications and other useful facts are specified below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity and thermal properties are included. For additional information please see the Chemeicals Information Center.

  • Properties
  • Safety Data
  • Products
  • Research
  • Isotopes
  • Other Elements

Chlorine Properties

Symbol: Cl Melting Point: -101.5 oC, -150.7 oF, 171.65 K
Atomic Number: 17 Boiling Point: -34.04 oC, -29.272 oF, 239.11 K
Atomic Weight: 35.45 Density: 2030 kg m-3
Element Category: halogen Liquid Density @ Melting Point: 1.5625 g·cm−3
Group, Period, Block: 17 (halogens), 3, p Specific Heat: N/A
    Heat of Vaporization 20.41 kJ·mol−1
CHEMICAL STRUCTURE Heat of Fusion 6.406 kJ·mol−1
Electrons: 17 Thermal Conductivity: 8.9 x 10−3  W·m−1·K−1
Protons: 17 Thermal Expansion: N/A
Neutrons: 18 Electrical Resistivity: (20 °C) > 10 Ω·m
Electron Configuration: [Ne]3s23p5 Electronegativity: 3.16 (Pauling scale)
Atomic Radius: N/A Tensile Strength: N/A
Covalent Radius: 102±4 pm Molar Heat Capacity: 33.949 J·mol−1·K−1
Van der Waals radius: 175 pm Young's Modulus: N/A
Oxidation States: 7, 6, 5, 4, 3, 2, 1, -1 (strongly acidic oxide) Shear Modulus: N/A
Phase: Gas Bulk Modulus: N/A
Crystal Structure: orthorhombic Poisson Ratio: N/A
Magnetic Ordering: diamagnetic Mohs Hardness: N/A
1st Ionization Energy: 1251.2 kJ·mol−1 Vickers Hardness: N/A
2nd Ionization Energy: 2298 kJ·mol−1 Brinell Hardness: N/A
3rd Ionization Energy: 3822 kJ·mol−1 Speed of Sound: (gas, 0 °C) 206 m·s−1
CAS Number: 7782-50-5 Abundance in typical human body, by weight: N/A
ChemSpider ID: 4514529 Abundance in typical human body, by atom: N/A
PubChem CID: 24526 Abundance in universe, by weight: N/A
MDL Number: MFCD00010934 Abundance in universe, by atom: N/A
EC Number: 231-959-5 Discovered By: Carl Wilhelm Scheele
Beilstein Number: 3902968 Discovery Date: 1774
SMILES Identifier: [Cl]  
InChI Identifier: InChI=1S/Cl Other Names: Le chlore, Chlor, Cloro, Klor

Health, Safety & Transportation Information for Chlorine

Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H270-H280-H315-H319-H331-H335-H400
Hazard Codes T,N
Risk Codes 23-36/37/38-50
Safety Precautions 9-45-61
RTECS Number FO2100000
Transport Information UN 1017 2.3
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)
Environment-Hazardous to the aquatic environment Skull and Crossbones-Acute Toxicity  Oxidizing Liquid - Oxidizing Gas Gas Cylinder - Gases Under Pressure

Chlorine Products

Aluminum Chloride
Aluminum Chloride, Anhydrous
Aluminum Chloride Solution
Aluminum Chloride Hexahydrate
Aluminum Phthalocyanine Chloride
Aluminum 1,8,15,22-tetrakis(phenylthio)-29H,31H-phthalocyanine Chloride
Aluminum 1,8,15,22-tetraphenoxy-29H,31H-phthalocyanine Chloride
Aluminum 2,3-naphthalocyanine Chloride
Aluminum 2,9,16,23-tetrakis(phenylthio)-29H,31H-phthalocyanine Chloride
Aluminum Chloride Tetrahydrofuran Complex
Ultra Dy Aluminum Chloride
Diethylaluminum Chloride
Di-i-butylaluminum Chloride
Tetraphenylarsonium(V) Chloride Hydrochloride Hydrate
Ammonium Chloropalladate
Ammonium Chloropalladite
Ammonium Chloroiride
Antimony Chloride SbCl3
Antimony Chloride SbCl5
Antimony Chloride Solution
Ultra Dry Antimony Chloride
Ultra Dry Antimony Chloride SbCl5
Arsenic Chloride
Arsenic Chloride Solution
Tetraphenylarsonium(V) Chloride Hydrate
Barium Chloride
Barium Chloride Dihydrate
Barium Chloride Solution
Ultra Dry Barium Chloride
Beryllium Chloride
Beryllium Chloride Solution
Bis(1,5-cyclooctadiene)dirhodium(I) dichloride
Bis(1,5-cyclooctadiene)diiridium(I) dichloride
Bismuth Chloride
Bismuth Chloride Solution
Ultra Dry Bismuth Chloride
Boron Chloride
Boron Chloride Solution
Boron Sub-2,3-naphthalocyanine Chloride
Boron Subphthalocyanine Chloride
Cadmium Chloride
Cadmium 113 Metal (Cadmium-113)
Cadmium 111 Chloride
Cadmium 113 Chloride
Cadmium Chloride Hemi(pentahydrate)
Cadmium Chloride Hydrate
Cadmium Chloride Solution
Ultra Dry Cadmium Chloride
Calcium Chloride
Calcium Chloride Pearl
Calcium Chloride Powder
Calcium Chloride Nanoparticles
Calcium Chloride Solution
Calcium Perchlorate Tetrahydrate
Ultra Dry Calcium Chloride
Carbon Chloride
Cerium Chloride
Ultra Dry Cerium Chloride
Cesium Chloride
Ultra Dry Cesium Chloride
Chloropentaammineiridium(III) Chloride
Chromium Chloride
Chromium(II) Chloride
Chromium(III) Chloride
Chromium(III) Chloride Hydrate
Chromium(III) Chloride HexaHydrate
Chromium(III) Chloride Tetrahydrofuran Complex
Chromium Chloride Solution
Chromyl Chloride
Cobalt Chloride
Cobalt(II) Chloride Hydrate
Cobalt Chloride Solution
Cobalt(III) Chloropentammine Chloride
trans-Dichlorobis(ethylenediamine)cobalt(III) Chloride
Hexammine Cobalt(III) Chloride
Ultra Dry Cobalt Chloride
Tris(ethylenediamine)cobalt(III) Chloride Dihydrate
Copper Chloride
Copper(I) Chloride - Bis(Lithium Chloride) Complex
Copper(II) Chloride Dihydrate
Copper Chloride Solution
Dysprosium Chloride
Dysprosium Chloride Solution
Dysprosium(III) Chloride Hexahydrate
Ultra Dry Dysprosium Chloride
Erbium Chloride
Erbium Chloride Solution
Ultra Dry Erbium Chloride
Europium Chloride
Europium Chloride Solution
Gadolinium Chloride
Gadolinium Chloride Solution
Gadolinium Chloride Hexahydrate
Gadolinium Chloride Hydrate
Ultra Dry Gadolinium Chloride
Gallium Chloride
Gallium Chloride Solution
Gallium(III) 2,3-naphthalocyanine Chloride
Gallium(III)-phthalocyanine Chloride
Ultra Dry Gallium Chloride
Germanium Chloride GeCl2
Germanium Chloride GeCl4
Germanium Chloride Solution
Gold(I) Chloride (AuCl)
Gold(III) Chloride (AuCl3)
Gold(III) Chloride Hydrate
Gold(III) Chloride Trihydrate
Gold(III) Chloride Solution
Digold Hexachloride
Tetragold Octachloride
1,3-Bis(2,4,6-trimethylphenyl)imidazol-2-ylidene Gold(I) Chloride 
Hafnium Chloride
Hafnium Oxychloride
Holmium Chloride
Holmium Chloride Solution
Hafnium Chloride Solution
Hafnium(IV) Chloride Tetrahydrofuran Complex
Hexaammineruthenium(III) Chloride
Bis(trimethylsilyl)amidohafnium(IV) Chloride
Indium Chloride
Indium Chloride Solution
Indium(III) Phthalocyanine Chloride
Iodine Chloride
Iridium Chloride
Iridium Chloride Solution
Iridium(III) Chloride Hydrochloride Hydrate
Chloroiridium Acid
Iridium Trichloride
Iridium Tetrachloride
Indium(III) Chloride Tetrahydrate
Pentaamminechloroiridium(III) Chloride
Pentamethylcyclopentadienyliridium(III) Chloride,dimer
Iron Chloride FeCl2
Iron Chloride FeCl3
Iron Chloride Solution
Iron(II) Chloride Tetrahydrate
Iron(III) Phthalocyanine Chloride
Ultra Dry Iron Chloride
2,3,7,8,12,13,17,18-Octaethyl-21H,23H-porphine Iron(III) Chloride
5,10,15,20-Tetrakis(4-methoxyphenyl)-21H,23H-porphine iron(III) chloride
5,10,15,20-Tetrakis(pentafluorophenyl)porphyrin iron(III) chloride complex
5,10,15,20-Tetrakis(pentafluorophenyl)-21H,23H-porphyrin iron(III) chloride
5,10,15,20-Tetraphenyl-21H,23H-porphine Iron(III) Chloride
Ferric Chloride
Ferric Chloride Hexahydrate
Ferrous Chloride
Lanthanum Chloride
Lanthanum(III) Chloride Hydrate
Lanthanum(III) Chloride Heptahydrate
Lanthanum Chloride Solution
Ultra Dry Lanthanum Chloride
Lead Chloride
Lead Chloride Solution
Ultra Dry Lead Chloride
Lithium Chloride
Cyclopentadienyltungsten(II) Tricarbonyl Chloride
Lithium Hexachloriridate
Ultra Dry Lithium Chloride
Lithium Potassium Chloride
Lutetium Chloride
Lutetium Chloride Solution
Magnesium Chloride
Magnesium Chloride Solution
Ultra Dry Magnesium Chloride
Manganese Chloride
Manganese Chloride Solution
Manganese(III) Phthalocyanine Chloride
Manganese Chloride Tetrahydrate
Ultra Dry Manganese Chloride
2,3,7,8,12,13,17,18-Octaethyl-21H,23H-porphine manganese(III) chloride
5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine chloride tetrakis(methochloride)
5,10,15,20-Tetrakis(4-sulfonatophenyl) -21H,23H-porphine Manganese(III) Chloride
5,10,15,20-Tetraphenyl-21H,23H-porphine manganese(III) Chloride
Mercury Ammonium Chloride
Mercury(I) Chloride
Mercury Chloride HgCl2
Mercury Chloride Hg2Cl2
Molybdenum Chloride
Molybdenum Chloride Solution
Neodymium Chloride
Neodymium(III) Chloride Hexahydrate
Neodymium Chloride Solution
Ultra Dry Neodymium Chloride
Nickel Chloride
Nickel(II) Chloride Hexahydrate
Nickel Chloride Solution
Ultra Dry Nickel Chloride
Bis(ethylenediamine)nickel(II) Chloride Hydrate
1,3-Bis(diphenylphosphino)propane Nickel(II) Chloride
Niobium Chloride NbCl3
Niobium Chloride NbCl5
Niobium Chloride Solution
Niobium(III) Chloride 1,2-dimethoxyethane Complex
Niobium(IV) Chloride Tetrahydrofuran Complex
Octylmagnesium Chloride
Osmium Chloride OsCl3
Osmium Chloride OsCl4
Osmium Chloride Solution
Phenylmagnesium Chloride
Ammonium Hexachloroosmate
Pentaammine(dinitrogen)osmium(II) Chloride
Tetraamminedioxoosmium(VI) Chloride
Palladium Chloride
Palladium Dichloride
Tetraamminepalladium(II) Dichloride
Palladium Trans-Dichlorodiammine
Dichlorodiammine Palladium
Tert-butyl Magnesium Chloride
Bis(ethylenediamine)palladium(II) Dichloride
Bis(triphenylphosphine)palladium(II) Dichloride
(1,3-Bis(diphenylphosphino)propane)palladium(II) Chloride
2'-(Dimethylamino)-2-biphenylyl-palladium(II) Chloride Dinorbornylphosphine Complex
2-(Dimethylaminomethyl)ferrocen-1-yl-palladium(II) Chloride Dinorbornylphosphine Complex
Allyl[1,3-bis(mesityl)imidazol-2-ylidene] palladium Chloride
Allyl[1,3-bis(2,6-diisopropylphenyl) imidazol-2-ylidene]palladium(II) Chloride
Allylpalladium(II) Chloride Dimer
Tetraamminepalladium(II) Chloride Monohydrate
Palladium Chloride Solution
[(R)-(+)-2,2'-Bis(diphenylphosphino)-1, 1'-binaphthyl]palladium(II) Chloride
1,4-Bis(diphenylphosphino)butane-palladium(II) Chloride
Platinum Chloride PtCl2
Platinum Chloride PtCl4
Platinum Dichloride
Platinum Tetrachloride
Platinum Chloride Solution
Chloro(2,2':6',2?-terpyridine)platinum(II) Chloride Dihydrate
Tetraammineplatinum Chloride
Tetraammineplatinum(II) Chloride Hydrate
Potassium Chloride
Potassium 40 Chloride
Potassium 41 Chloride
Potassium Chloroplatinate
Potassium Chloropalladate
Potassium Chloropalladite
Potassium Gold(III) Chloride
Potassium Tetrachloroplatinate
Dipotassium Hexachloroiridate
Ultra Dry Potassium Chloride
Praseodymium Chloride
Praseodymium Chloride Solution
Ultra Dry Praseodymium Chloride
Rhenium Chloride ReCl3
Rhenium Chloride ReCl4
Rhenium Chloride Solution
Rhodium Chloride
Rhodium Trichloride Hydrate
(Bicyclo[2.2.1]hepta-2,5-diene)-rhodium(I) Chloride Dimer
Bis(ethylenediamine)dioxorhenium(V) Chloride
Bis(triphenylphosphine)rhodium(I) Carbonyl Chloride
Pentamethylcyclopentadienylrhodium(III) chloride,dimer
trans-Dichlorotetrakis(pyridine)rhodium(III) Chloride
Tris(ethylenediamine)rhodium(III) Chloride Trihydrate
Tris(triphenylphosphine)rhodium(I) Chloride
Rhenium Chloride
Rhenium(V) Chloride
Rubidium Chloride
Rubidium Chloride Solution
Rubidium 87 Chloride
Ruthenium Chloride
Ruthenium Chloride Solution
Ruthenium(II) chloride 1,5-cyclooctadiene Complex
Ruthenium(III) Chloride Trihydrate
Ruthenium Trichloride Hydrate
Benzeneruthenium(II) chloride, dimer
Bis(triphenylphosphine)ruthenium(II) Dicarbonyl Chloride
Chloropentaammineruthenium(II) Chloride
Hexaammineruthenium(II) Chloride
Pentaamminechlororuthenium(III) Chloride
(R)-2-[(RP)-2-(Diphenylphosphino)ferrocenyl] -4-isopropyl-2-oxazoline triphenylphosphine ruthenium(II)chloride Complex
Tris(2,2'-bipyridine)ruthenium(II) Chloride Hexahydrate
Samarium Chloride SmCl2
Samarium Chloride SmCl3
Samarium Chloride Solution
Ultra Dry Samarium Chloride
Scandium Chloride
Scandium Chloride Solution
Scandium Chloride Hydrate
Scandium(III) Chloride Hexahydrate
Selenium Chloride Se2Cl2
Selenium Chloride SeCl4
Selenium Chloride Solution
Silicon Chloride
Silicon Chloride Solution
(Triisopropylsiloxy)methyl Chloride
2-(Trimethylsilyl)ethanesulfonyl Chloride
Silver Chlorate
Silver Chloride
Ultra Dry Silver Chloride
Silver Chloride Solution
Sodium Chloride
Sodium 35 Chloride
Sodium Chloride Solution
Sodium Chloroplatinate
Sodium Hexachloroiridate Hexahydrate
Sodium Tetrachloroaurate(III) Hydrate
Ultra Dry Sodium Chloride
Sodium Pyrophosphate Tetrabasic
Strontium Chloride
Strontium Chloride Solution
Ultra Dry Strontium Chloride
Tantalum Chloride TaCl3
Tantalum Chloride TaCl5
Tantalum Chloride Solution
Tellurium Chloride TeCl2
Tellurium Chloride TeCl4
Tellurium Chloride Solution
Terbium Chloride
Terbium Chloride Solution
Ultra Dry Terbium Chloride
Thallium Chloride TlCl
Thallium Chloride TlCl3
Thallium Chloride Solution
Thallium Chloride Tetrahydrate
Ultra Dry Thallium Chloride
Thorium Chloride
Thorium Chloride Solution
Thulium Chloride
Thulium Chloride Solution
Tin Chloride
Tin Chloride Anhydrous
Tin Chloride Solution
Titanium(III) Chloride-Aluminum Chloride
Titanium(IV) Chloride Tetrahydrofuran Complex
Ultra Dry Tin Chloride
Titanium Chloride
Titanium Chloride Solution
Titanium(III) Chloride Tetrahydrofuran Complex
Tungsten Chloride
Tungsten Chloride Solution
Bis(cyclopentadienyl) Tungsten(IV) Chloride Hydride
Urainum Chloride
Uranium Chloride Solution
Vanadium Chloride VCl2
Vanadium Chloride VCl3
Vanadium Chloride VCl4
Vanadium Chloride Solution
Vanadium(III) Chloride Tetrahydrofuran Complex
Bis(cyclopentadienyl) Vanadium(III) Chloride
Ytterbium Chloride
Ytterbium Chloride Solution
Ytterbium Perchlorate Solution
Ultra Dry Ytterbium Chloride
Yttrium Chloride
Yttrium Chloride Solution
Ultra Dry Yttrium Chloride
Zinc Chloride
Zinc Chloride Solution
p-Diazo-N,N-diethyl-m-toluidine Hemi(Zinc Chloride) Salt 
Ultra Dry Zinc Chloride
Zirconium Chloride
Zirconium Chloride Solution
Zirconium Dichloride Oxide Hydrate
Bis(cyclopentadienyl)zirconium(IV) Chloride Hydride
(1R,2R)-(-)-[1,2-Cyclohexanediamino-N,N'-bis(3,5-di-t-butylsalicyl-idene)]aluminum(III) Chloride
(1S,2S)-(+)-[1,2-Cyclohexanediamino-N,N'-bis(3,5-di-t-butylsalicyl-idene)]aluminum(III) Chloride

Recent Research & Development for Chlorine

  • Kunihiko Tanaka, Minoru Kato, Hisao Uchiki, Effects of chlorine and carbon on Cu2ZnSnS4 thin film solar cells prepared by spray pyrolysis deposition, Journal of Alloys and Compounds, Volume 616, 15 December 2014
  • Saira Bano, Asif Mahmood, Seong Joong Kim, Kew-Ho Lee, Chlorine resistant binary complexed NaAlg/PVA composite membrane for nanofiltration, Separation and Purification Technology, Volume 137, 24 November 2014
  • Li-Fen Liu, Zhi-Bin Cai, Jiang-Nan Shen, Li-Xiang Wu, Eric M.V. Hoek, Cong-Jie Gao, Fabrication and characterization of a novel poly(amide-urethane@imide) TFC reverse osmosis membrane with chlorine-tolerant property, Journal of Membrane Science, Volume 469, 1 November 2014
  • Chen-Chien Li, Kuei-Shu Chang-Liao, Li-Ting Chen, Chung-Hao Fu, Hao-Zhi Hong, Mong-Chi Li, Wei-Fong Chi, Chun-Chang Lu, Zong-Hao Ye, Tien-Ko Wang, Low inversion equivalent oxide thickness and enhanced mobility in MOSFETs with chlorine plasma interface engineering, Solid-State Electronics, Volume 101, November 2014
  • Seyyed Javad Sabounchei, Mahbubeh Pourshahbaz, Sadegh Salehzadeh, Mehdi Bayat, Roya Karamian, Mostafa Asadbegy, Hamid Reza Khavasi, New Chlorine Bridged Binuclear Silver(I) Complexes of Bidentate Phosphorus Ylides: Synthesis, Spectroscopy, Theoretical and Anti-Bacterial Studies, Polyhedron, Available online 5 October 2014
  • Liqun Duan, Qingsong Ma, Zhaohui Chen, Etching process of silicon carbide from polysiloxane by chlorine, Corrosion Science, Volume 87, October 2014
  • Hyung Park, Wooram Park, Kun Na, Doxorubicin loaded singlet-oxygen producible polymeric micelle based on chlorine e6 conjugated pluronic F127 for overcoming drug resistance in cancer, Biomaterials, Volume 35, Issue 27, September 2014
  • Alexandre Desforges, Guillaume Mercier, Claire Hérold, Jérôme Gleize, François Le Normand, Brigitte Vigolo, Improvement of carbon nanotube stability by high temperature oxygen/chlorine gas treatment, Carbon, Volume 76, September 2014
  • Zhong Chen, Xiao Xia Li, Guoping Du, Quanmao Yu, Bo Li, Xinyang Huang, Luminescence properties of chlorine and oxygen co-doped ZnS nanoparticles synthesized by a solid-state reaction, Ceramics International, Volume 40, Issue 8, Part B, September 2014
  • D. Banerjee, K.K. Chattopadhyay, Enhanced field emission properties of PECVD synthesized chlorine doped diamond like carbon thin films, Surface and Coatings Technology, Volume 253, 25 August 2014

Chlorine Isotopes

Chlorine has two stable isotopes: 35Cl and 37Cl.

Nuclide Symbol Isotopic Mass Half-Life Nuclear Spin
35Cl 34.96885268 Stable 3/2+
37Cl 36.96590259 Stable 3/2+