Chlorine

• Formula: Cl₂
• Molecular weight: 70.906
• IUPAC Standard InChI: InChI=1S/Cl2/c1-2 Copy

  
• IUPAC Standard InChIKey: KZBUYRJDOAKODT-UHFFFAOYSA-N Copy
• CAS Registry Number: 7782-50-5
• Chemical structure:
  This structure is also available as a 2d Mol file or as a computed 3d SD file
  The 3d structure may be viewed using Java or Javascript.
• Other names: Cl2; Bertholite; Chloor; Chlor; Chlore; Chlorine mol.; Cloro; Molecular chlorine; UN 1017; Diatomic chlorine
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Henry's Law data
  • Ion clustering data
  • Constants of diatomic molecules
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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Gas phase thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
    C_p = heat capacity (cal/mol*K)
    H° = standard enthalpy (kcal/mol)
    S° = standard entropy (cal/mol*K)
    t = temperature (K) / 1000.

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View table.

Phase change data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (atm)
    T = temperature (K)

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Reaction thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
B - John E. Bartmess
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

 +  = Cl₃^-

By formula: Cl^- + Cl₂ = Cl₃^-

 +  =

By formula: C₂Cl₄ + Cl₂ = C₂Cl₆

 +  = ( • )

By formula: Cl^- + Cl₂ = (Cl^- • Cl₂)

 +  =

By formula: C₄F₆ + Cl₂ = C₄Cl₂F₆

 +  =

By formula: C₃F₆ + Cl₂ = C₃Cl₂F₆

 +  =

By formula: Cl₂ + C₂ClF₃ = C₂Cl₃F₃

 +  =

By formula: Cl₂ + C₂Cl₂F₂ = C₂Cl₄F₂

 +  =

By formula: C₂F₄ + Cl₂ = C₂Cl₂F₄

 +  =  + 

By formula: C₂H₄Cl₂ + Cl₂ = HCl + C₂H₃Cl₃

 +  =  + 

By formula: CHCl₃ + Cl₂ = CCl₄ + HCl

 +  =

By formula: C₂H₄ + Cl₂ = C₂H₄Cl₂

 +  =

By formula: C₂H₂Cl₂ + Cl₂ = C₂H₂Cl₄

 +  =  + 

By formula: BrCl + CClF₃ = CBrF₃ + Cl₂

 +  = C₂BrF₅ + 

By formula: BrCl + C₂ClF₅ = C₂BrF₅ + Cl₂

=  + 

By formula: C₂H₂Cl₂ = C₂H₂ + Cl₂

 +  =

By formula: C₄F₈ + Cl₂ = C₄Cl₂F₈

C₅F₁₀ +  = C₅Cl₂F₁₀

By formula: C₅F₁₀ + Cl₂ = C₅Cl₂F₁₀

=  + 

By formula: C₂Cl₆ = C₂Cl₄ + Cl₂

 +  =

By formula: C₄F₈ + Cl₂ = C₄Cl₂F₈

 +  =  + 

By formula: C₆H₁₁Cl + HCl = C₆H₁₂ + Cl₂

 +  =  + 

By formula: C₆H₆ + Cl₂ = C₆H₅Cl + HCl

 +  =

By formula: Cl₂ + C₂HCl₃ = C₂HCl₅

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
B - John E. Bartmess

View reactions leading to Cl₂⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

Appearance energy determinations

Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

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Additional Data

References

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Cox, Wagman, et al., 1984
Cox, J.D.; Wagman, D.D.; Medvedev, V.A., CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp., New York, 1984, 1. [all data]

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Thiele and Schulte, 1920
Thiele, A.; Schulte, E., Binary equilibrium systems with solid carbon dioxide, Z. Phys. Chem., Stoechiom. Verwandtschaftsl., 1920, 96, 312-42. [all data]

Angus, Armstrong, et al., 1984
Angus, S.; Armstrong, B.; de Reuck, K.M., International Thermodynamic Tables of the Fluid State - Chlorine, Pergamon, Oxford, 1984. [all data]

Giauque and Powell, 1939
Giauque, W.F.; Powell, T.M., Chlorine. The Heat Capacity, Vapor Pressure, Heats of Fusion and Vaporiza- tion, and Entropy, J. Am. Chem. Soc., 1939, 61, 1970. [all data]

Ambrose, Hall, et al., 1979
Ambrose, D.; Hall, D.J.; Lee, D.A.; Lewis, G.B., Vapor pressure of chlorine, J. Chem. Thermodyn., 1979, 11, 1089. [all data]

Stull, 1947
Stull, Daniel R., Vapor Pressure of Pure Substances. Organic and Inorganic Compounds, Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022 . [all data]

Nizzi, Pommerening, et al., 1998
Nizzi, K.E.; Pommerening, C.A.; Sunderlin, L.S., Gas-phase thermochemistry of polyhalide anions, J. Phys. Chem. A, 1998, 102, 39, 7674-7679, https://doi.org/10.1021/jp9824508 . [all data]

Robbiani and Franklin, 1979
Robbiani, R.; Franklin, J.L., Formation of the trihalide ion Cl₃- in the gas phase, J. Am. Chem. Soc., 1979, 101, 764. [all data]

Lee, Smith, et al., 1979
Lee, L.C.; Smith, G.P.; Moseley, J.T.; Cosby, P.C.; Guest, J.A., Photodissociation and photodetachment of Cl₂-, ClO-, Cl₃-, and BrCl₂-, J. Chem. Phys., 1979, 70, 3237. [all data]

Kirkbride, 1956
Kirkbride, F.W., The heats of chlorination of some hydrocarbons and their chloro-derivatives, J. Appl. Chem., 1956, 6, 11-21. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Robbiani and Franklin, 1979, 2
Robbiani, R.; Franklin, J.L., Negative ion-molecule reaction in sulfuryl halides, J. Am. Chem. Soc., 1979, 101, 3709. [all data]

National Bureau of Standards, 1968
National Bureau of Standards, US, Technical Note 270 - 3 in The NBS Tables of Chemical Thermodynamic Properties, 1968. [all data]

Lacher, McKinley, et al., 1949
Lacher, J.R.; McKinley, J.J.; Walden, C.; Lea, K.; Park, J.D., Reaction heats of organic fluorine compounds. II. The vapor phase heats of chlorination of some simple fluoroolefins, J. Am. Chem. Soc., 1949, 71, 1334-1337. [all data]

Lacher, McKinley, et al., 1949, 2
Lacher, J.R.; McKinley, J.J.; Snow, C.M.; Michel, L.; Nelson, G.; Park, J.D., Reaction heats of organic fluorine compounds. I. Apparatus and the heat of chlorination of tetrafluoroethylene, J. Am. Chem. Soc., 1949, 71, 1330-1334. [all data]

Conn, Kistiakowsky, et al., 1938
Conn, J.B.; Kistiakowsky, G.B.; Smith, E.A., Heats of organic reactions. VII. Addition of halogens to olefins, J. Am. Chem. Soc., 1938, 60, 2764-2771. [all data]

Coomber and Whittle, 1967
Coomber, J.W.; Whittle, E., Bond dissociation energies from equilibrium studies. Part 3.-D(CF₃-Cl), D(C₂F₅-Cl) and the enthalpy of formation of CF₃Cl, Trans. Faraday Soc., 1967, 63, 2656-2667. [all data]

Laursen and Pimentel, 1989
Laursen, S.L.; Pimentel, G.C., Matrix-induced intersystem crossing in the photochemistry of the 1,2-dichloroethenes, J. Phys. Chem., 1989, 93, 2328-2333. [all data]

Lacher, Kianpour, et al., 1957
Lacher, J.R.; Kianpour, A.; Park, J.D., Reaction heats of organic halogen compounds. X. Vapor phase heats of hydrobromination of cyclopropane and propylene, J. Phys. Chem., 1957, 61, 1124-1125. [all data]

Lacher, Kianpour, et al., 1957, 2
Lacher, J.R.; Kianpour, A.; Park, J.D., Reaction heats of organic halogen compounds. VIII. The heats of chlorination of perfluorinated butene-1 pentene-1 and isobutene, J. Phys. Chem., 1957, 61, 584-586. [all data]

Puyo, Balesdent, et al., 1963
Puyo, J.; Balesdent, D.; Niclause, M.; Dzierzynski, M., Etude analytique et thermodynamique de la pyrolyse de l'hexachloroethane en phase gazeuse., Compt. Rend., 1963, 256, 3471-3473. [all data]

Bowen, Liesegang, et al., 1983
Bowen, K.H.; Liesegang, G.W.; Sanders, R.A.; Herschbach, D.W., Electron Attachment to Molecular Clusters by Collisional Charge Transfer, J. Phys. Chem., 1983, 87, 4, 557-565, https://doi.org/10.1021/j100227a009 . [all data]

Ayala, Wentworth, et al., 1981
Ayala, J.A.; Wentworth, W.E.; Chen, E.C.M., Electron attachment to halogens, J. Phys. Chem., 1981, 85, 768. [all data]

Dispert and Lacmann, 1977
Dispert, H.; Lacmann, K., Chemiionization in alkali-halogen reactions: Evidence for ion formation by alkali dimers, Chem. Phys. Lett., 1977, 47, 533. [all data]

Hughes, Lifschitz, et al., 1973
Hughes, B.M.; Lifschitz, C.; Tiernan, T.O., Electron affinities from endothermic negative-ion charge-transfer reactions. III. NO, NO₂, S₂, CS₂, Cl₂, Br₂, I₂, and C₂H, J. Chem. Phys., 1973, 59, 3162. [all data]

Baeda, 1972
Baeda, A.P.M., The adiabatic electron affinities of Cl₂, Br₂, I₂, IBr, NO₂, and O₂, Physica, 1972, 59, 541. [all data]

Dunkin, Fehsenfeld, et al., 1972
Dunkin, D.B.; Fehsenfeld, F.C.; Ferguson, F.E., Thermal energy rate constants for the reactions NO₂^- + Cl₂ → Cl₂^-, Cl₂^- + NO₂ Ü Cl^-, HS^- + NO₂ Ü NO₂^-, HS^- + Cl₂ Ü Cl₂^-, and S^- + NO₂ Ü NO₂^-, Chem. Phys. Lett., 1972, 15, 257. [all data]

Chupka, Berkowitz, et al., 1971
Chupka, W.A.; Berkowitz, J.; Gutman, D., Electron Affinities of Halogen Diatomic Molecules as Determined by Endoergic Charge Exchange, J. Chem. Phys., 1971, 55, 6, 2724, https://doi.org/10.1063/1.1676487 . [all data]

DeCorpo and Franklin, 1971
DeCorpo, J.J.; Franklin, J.L., Electron affinities of the halogen molecules by dissociative electron attachment, J. Chem. Phys., 1971, 54, 1885. [all data]

Hubers, Kleyn, et al., 1976
Hubers, M.M.; Kleyn, A.W.; Los, J., Ion pair formation in alkali-halogen collisions at high velocities, Chem. Phys., 1976, 17, 303. [all data]

Lacmann and Herschbach, 1970
Lacmann, K.; Herschbach, D.R., Collisional Excitation and Ionization of K Atoms by Diatomic Molecules: Role of Ion-pair States, Chem. Phys. Lett., 1970, 6, 2, 106, https://doi.org/10.1016/0009-2614(70)80144-0 . [all data]

Yencha, Hopkirk, et al., 1995
Yencha, A.J.; Hopkirk, A.; Hiraya, A.; Donovan, R.J.; Goode, J.G.; Maier, R.R.J.; King, G.C.; Kvaran, A., Threshold photoelectron spectroscopy of Cl₂ and Br₂ up to 35 eV, J. Phys. Chem., 1995, 99, 7231. [all data]

Van Lonkhuyzen and De Lange, 1984
Van Lonkhuyzen, H.; De Lange, C.A., High-resolution UV photoelectron spectroscopy of diatomic halogens, Chem. Phys., 1984, 89, 313. [all data]

Huber and Herzberg, 1979
Huber, K.P.; Herzberg, G., Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules,, Van Nostrand Reinhold Co., 1979, ,1. [all data]

Potts and Price, 1971
Potts, A.W.; Price, W.C., Photoelectron spectra of the halogens and mixed halides ICI and lBr, J. Chem. Soc. Faraday Trans., 1971, 67, 1242. [all data]

Dibeler, Walker, et al., 1971
Dibeler, V.H.; Walker, J.A.; McCulloh, K.E.; Rosenstock, H.M., Effect of hot bands on the ionization threshold of some diatomic halogen molecules, Intern. J. Mass Spectrom. Ion Phys., 1971, 7, 209. [all data]

Cornford, Frost, et al., 1971
Cornford, A.B.; Frost, D.C.; McDowell, C.A.; Ragle, J.L.; Stenhouse, I.A., Photoelectron spectra of the halogens, J. Chem. Phys., 1971, 54, 2651. [all data]

Anderson, Mamantov, et al., 1971
Anderson, C.P.; Mamantov, G.; Bull, W.E.; Grimm, F.A.; Carver, J.C.; Carlson, T.A., Photoelectron spectrum of chlorine monofluoride, Chem. Phys. Lett., 1971, 12, 137. [all data]

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Dyke, Josland, et al., 1984
Dyke, J.M.; Josland, G.D.; Snijders, J.G.; Boerrigter, P.M., Ionization energies of the diatomic halogens and interhalogens studied with relativistic hartree-fock-slater calculations, Chem. Phys., 1984, 91, 419. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Frost and McDowell, 1959
Frost, D.C.; McDowell, C.A., Recent electron impact studies on simple molecules (O₂, Cl₂, I₂), Advan. Mass Spectrom., 1959, 1, 413. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), References

• Symbols used in this document:
  

  AE	Appearance energy
  EA	Electron affinity
  Pc	Critical pressure
  Ptriple	Triple point pressure
  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  Tboil	Boiling point
  Tc	Critical temperature
  Ttriple	Triple point temperature
  ΔrH°	Enthalpy of reaction at standard conditions
  ρc	Critical density

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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