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
  • Reaction thermochemistry data
  • Henry's Law data
  • Constants of diatomic molecules
  • References
  • Notes
• Other data available:
  • Phase change data
  • Gas phase ion energetics data
  • Ion clustering data
  • Mass spectrum (electron ionization)
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
• Options:
  • Switch to calorie-based units

Data at NIST subscription sites:

• NIST / TRC Web Thermo Tables, "lite" edition (thermophysical and thermochemical data)
• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.

Gas phase thermochemistry data

Go To: Top, Reaction thermochemistry data, Henry's Law data, Constants of diatomic molecules, References, Notes

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 (J/mol*K)
    H° = standard enthalpy (kJ/mol)
    S° = standard entropy (J/mol*K)
    t = temperature (K) / 1000.

View plot Requires a JavaScript / HTML 5 canvas capable browser.

View table.

Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Henry's Law data, Constants of diatomic molecules, 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:
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

Henry's Law data

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Constants of diatomic molecules, 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: Rolf Sander

Henry's Law constant (water solution)

k_H(T) = k°_H exp(d(ln(k_H))/d(1/T) ((1/T) - 1/(298.15 K)))
k°_H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(k_H))/d(1/T) = Temperature dependence constant (K)

Constants of diatomic molecules

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Henry's Law 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: Klaus P. Huber and Gerhard H. Herzberg

Data collected through September, 1976

Notes

References

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Henry's Law data, Constants of diatomic molecules, 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]

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]

Iczkowski, Margrave, et al., 1960
Iczkowski, R.P.; Margrave, J.L.; Green, J.W., Absorption spectrum of chlorine in the vacuum ultraviolet, J. Chem. Phys., 1960, 33, 1261. [all data]

Lee and Walsh, 1959
Lee, J.; Walsh, A.D., The vacuum ultra-violet absorption spectra of the halogen molecules, Trans. Faraday Soc., 1959, 55, 1281. [all data]

Asundi and Venkateswarlu, 1947
Asundi, R.K.; Venkateswarlu, P., Spectra of the Halogens, I₂, Br₂ and Cl₂, Indian J. Phys., 1947, 21, 101-118. [all data]

Haranath and Rao, 1958
Haranath, P.B.V.; Rao, P.T., Band spectra of iodine, chlorine, and bromine in the spectral region 2400-1400 A, J. Mol. Spectrosc., 1958, 2, 428. [all data]

Khanna, 1959
Khanna, B.N., Emission spectrum of chlorine excited in the presence of argon, Proc. Indian Acad. Sci. Sect. A, 1959, 49, 293-301. [all data]

Venkateswarlu and Khanna, 1959
Venkateswarlu, P.; Khanna, B.N., Emission spectrum of chlorine excited in the presence of argon. Part I. The band system in the region 2600-2390 Å, Proc. Indian Acad. Sci. Sect. A, 1959, 49, 117-127. [all data]

Wieland, Tellinghuisen, et al., 1972
Wieland, K.; Tellinghuisen, J.B.; Nobs, A., The band systems E → B(4000-4360 Å) and F → X(2530-2740 Å) of ¹²⁷I₂ and ¹²⁹I₂, and the corresponding system E = B of Br₂ and Cl₂, J. Mol. Spectrosc., 1972, 41, 69. [all data]

Cordes and Sponer, 1930
Cordes, H.; Sponer, H., Die molekulabsorption des chlors, broms, jodchlorids und jodbromids im aubersten ultraviolett, Z. Phys., 1930, 63, 334. [all data]

Gibson and Bayliss, 1933
Gibson, G.E.; Bayliss, N.S., Variation with temperature of the continuous absorption spectrum of diatomic molecules: Part I. Experimental, the absorption spectrum of chlorine, Phys. Rev., 1933, 44, 188. [all data]

Sulzer and Wieland, 1952
Sulzer, P.; Wieland, K., Intensitatsverteilung eines kontinuierlichen Absorptions-spectrums in Abhangigkeit von Temperatur und Wellenzahl, Helv. Phys. Acta, 1952, 25, 653-676. [all data]

Jacobs and Giedt, 1965
Jacobs, T.A.; Giedt, R.R., Absorption coefficients of Cl₂ at high temperatures, J. Quant. Spectrosc. Radiat. Transfer, 1965, 5, 457. [all data]

Clyne and Stedman, 1968
Clyne, M.A.A.; Stedman, D.H., Recombination of ground-state halogen atoms. Part 1. Radiative recombination of chlorine atoms, Trans. Faraday Soc., 1968, 64, 1816. [all data]

Palmer and Carabetta, 1968
Palmer, H.B.; Carabetta, R.A., Radiative recombination of chlorine atoms in shock waves: a re-examination, J. Chem. Phys., 1968, 49, 2466. [all data]

Coxon, 1973
Coxon, J.A., Chapt. 4. Low-lying electronic states of diatomic halogen molecules in Molecular Spectroscopy. Volume 1, Barrow,R.F.; Long,D.A.; Millen,D.J., ed(s)., The Chemical Society, Burlington House, London, W1V 0BN, 1973, 177-228. [all data]

Bondybey and Fletcher, 1976
Bondybey, V.E.; Fletcher, C., Photophysics of low lying electronic states of Cl₂ in rare gas solids, J. Chem. Phys., 1976, 64, 3615. [all data]

Winkel, Hunt, et al., 1969
Winkel, R.G.; Hunt, J.L.; Clouter, M.J., Pressure-induced fundamental infrared absorption band of gaseous chlorine, J. Chem. Phys., 1969, 50, 1298. [all data]

Holzer, Murphy, et al., 1970
Holzer, W.; Murphy, W.F.; Bernstein, H.J., Resonance Raman effect and resonance fluoroscence in halogen gases, J. Chem. Phys., 1970, 52, 399. [all data]

Hochenbleicher and Schrotter, 1971
Hochenbleicher, G.; Schrotter, H.W., Observation of hot bands in the Raman spectra of Cl₂ gas and CCl₄ vapor, Appl. Spectrosc., 1971, 25, 3, 360-362. [all data]

Hendra and Vear, 1972
Hendra, P.J.; Vear, C.J., The pure rotational laser Raman spectrum of chlorine, Spectrochim. Acta, Part A, 1972, 28, 1949-1961. [all data]

Wallart, 1972
Wallart, F., Study of vibrational hot bands by Raman spectroscopy - application to chlorine and bromine chloride, Can. J. Spectrosc., 1972, 17, 128. [all data]

Edwards, Good, et al., 1976
Edwards, H.G.M.; Good, E.A.M.; Long, D.A., Pure rotational Raman spectra of the chlorine species, ³⁵Cl₂ and ³⁵Cl³⁷Cl, J. Chem. Soc. Faraday Trans. 2, 1976, 72, 927-933. [all data]

Rao and Venkateswarlu, 1962
Rao, Y.V.; Venkateswarlu, P., Vacuum ultraviolet resonance spectrum of Cl₂ molecule, J. Mol. Spectrosc., 1962, 9, 173. [all data]

Douglas and Hoy, 1975
Douglas, A.E.; Hoy, A.R., The resonance fluorescence spectrum of Cl₂ in the vacuum ultraviolet, Can. J. Phys., 1975, 53, 1965-1975. [all data]

Busch, Mahoney, et al., 1969
Busch, G.E.; Mahoney, R.T.; Morse, R.I., Translational spectroscopy: Cl₂ photodissociation, J. Chem. Phys., 1969, 51, 449. [all data]

Child and Bernstein, 1973
Child, M.S.; Bernstein, R.B., Diatomic interhalogens: systematics and implications of spectroscopic interatomic potentials and curve crossings, J. Chem. Phys., 1973, 59, 5916. [all data]

Brith, Rowe, et al., 1975
Brith, M.; Rowe, M.D.; Schnepp, O.; Stephens, P.J., The magnetic circular dichroism spectrum of the halogen molecules I₂, Br₂, Cl₂. Resolution of overlapping continua, Chem. Phys., 1975, 9, 57. [all data]

Douglas, Moller, et al., 1963
Douglas, A.E.; Moller, C.K.; Stoicheff, B.P., Can. J. Phys., 1963, 41, 1174. [all data]

Clyne and Coxon, 1970
Clyne, M.A.A.; Coxon, J.A., The visible band absorption spectrum of chlorine, J. Mol. Spectrosc., 1970, 33, 381. [all data]

Clyne and Coxon, 1967
Clyne, M.A.A.; Coxon, J.A., The formation and detection of some low-lying excited electronic states of BrCl and other halogens, Proc. R. Soc. London A, 1967, 298, 424. [all data]

Richards and Barrow, 1962
Richards, W.G.; Barrow, R.F., Rotational analysis of the A³Π_0+,u - X¹Σ_g⁺ system of the chlorine molecule, Proc. Chem. Soc. London, 1962, 297. [all data]

Le Roy, 1973
Le Roy, R.J., Chapt. 3. Energy levels of a diatomic near dissociation in Molecular Spectroscopy. Volume 1, Barrow,R.F.; Long,D.A.; Millen,D.J., ed(s)., The Chemical Society, Burlington House, London, W1V 0BN, 1973, 113-175. [all data]

LeRoy, 1974
LeRoy, R.J., Long-range potential coefficients from RKR turning points: C₆ and C₈ for B(³Π_0u⁺)-state Cl₂, Br₂, and I₂, Can. J. Phys., 1974, 52, 246. [all data]

LeRoy and Bernstein, 1971
LeRoy, R.J.; Bernstein, R.B., Dissociation energies and long-range potentials of diatomic molecules from vibrational spacings: the halogens, J. Mol. Spectrosc., 1971, 37, 109. [all data]

Goscinski, 1972
Goscinski, O., Outer vibrational turning points near dissociation in the B(³Π_0u⁺) state of Br₂ and Cl₂, Mol. Phys., 1972, 24, 655. [all data]

LeRoy, 1972
LeRoy, R.J., Dependence of the diatomic rotational constant B_v on the long-range internuclear potential, Can. J. Phys., 1972, 50, 953. [all data]

Yee and Stone, 1973
Yee, K.K.; Stone, T.J., Analysis of RKR long-range potentials of the B³Π_0u+ states of Br₂ and Cl₂, Mol. Phys., 1973, 26, 1169. [all data]

Coxon, 1971
Coxon, J.A., Franck-Condon factors and r-centroids for halogen molecules. I. The B³Π(0_u⁺)-X¹Σ_g⁺ system of ³⁵Cl₂, J. Quant. Spectrosc. Radiat. Transfer, 1971, 11, 1355. [all data]

Ault, Howard, et al., 1975
Ault, B.S.; Howard, W.F.; Andrews, L., Laser-induced fluorescence and Raman spectra of chlorine and bromine molecules isolated in inert matrices, J. Mol. Spectrosc., 1975, 55, 217. [all data]

Radziemski and Kaufman, 1969
Radziemski, L.J., Jr.; Kaufman, V., Wavelengths, energy levels, and analysis of neutral atomic chlorine (Cl I), J. Opt. Soc. Am., 1969, 59, 4, 424-443. [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]

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]

Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J., Ionization potentials of some molecules, J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Henry's Law data, Constants of diatomic molecules, References

• Symbols used in this document:
  

  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  d(ln(kH))/d(1/T)	Temperature dependence parameter for Henry's Law constant
  k°H	Henry's Law constant at 298.15K
  ΔrH°	Enthalpy of reaction at standard conditions

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
• The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
• Customer support for NIST Standard Reference Data products.