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Cyclobutadiene


Gas phase thermochemistry data

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, 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: Glushko Thermocenter, Russian Academy of Sciences, Moscow

Constant pressure heat capacity of gas

Cp,gas (cal/mol*K) Temperature (K) Reference Comment
7.94950.Dorofeeva O.V., 1986 
8.035100.
8.726150.
10.24200.
13.40273.15
14.57 ± 0.60298.15
14.66300.
19.14400.
22.86500.
25.820600.
28.200700.
30.155800.
31.793900.
33.1811000.
34.3671100.
35.3851200.
36.2641300.
37.0221400.
37.6791500.

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Vibrational and/or electronic energy levels, 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
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C4H4+ (ion structure unspecified)

Ionization energy determinations

IE (eV) Method Reference Comment
8.16 ± 0.03PEKohn and Chen, 1993LL
9.55EILi and McGee, 1969RDSH
8.2EIHedaya, Miller, et al., 1969RDSH
8.5DERDewar and Worley, 1969RDSH
8.24PEKreile, Munzel, et al., 1986Vertical value; LBLHLM

Vibrational and/or electronic energy levels

Go To: Top, Gas phase 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: Marilyn E. Jacox

State:   X


Vib. 
sym. 
 No.   Approximate 
 type of mode 
 cm-1   Med.   Method   References

ag CH stretch 3140 ± 5 Ne Ra Arnold, Radziszewski, et al., 1991
CH stretch 3140 ± 5 Ar Ra Arnold, Radziszewski, et al., 1991
C=C stretch 1678 ± 5 Ne Ra Arnold, Radziszewski, et al., 1991
C=C stretch 1678 ± 5 Ar Ra Arnold, Radziszewski, et al., 1991
CH deform. 1059 ± 5 Ne Ra Arnold, Radziszewski, et al., 1991
CH deform. 1059 ± 5 Ar Ra Arnold, Radziszewski, et al., 1991
CH deform. 989 ± 5 Ne Ra Arnold, Radziszewski, et al., 1991
CH deform. 989 ± 5 Ar Ra Arnold, Radziszewski, et al., 1991
b1u CH stretch 3124 w m Ar IR Maier, 1988
Orendt, Arnold, et al., 1988
Arnold and Michl, 1993
C=C stretch 1527 Ne IR Orendt, Arnold, et al., 1988
C=C stretch 1526 w Ar IR Masamune, Souto-Bachiller, et al., 1978
Maier, 1988
Orendt, Arnold, et al., 1988
Arnold and Michl, 1993
CH deform. 1028 w Ar IR Maier, 1988
b2g CH OPLA deform. 531 ± 5 Ne Ra Arnold, Radziszewski, et al., 1991
CH OPLA deform. 531 ± 5 Ar Ra Arnold, Radziszewski, et al., 1991
b2u CH stretch 3105 w m Ar IR Maier, 1988
Orendt, Arnold, et al., 1988
Arnold and Michl, 1993
CH deform. 1244 Ne IR Orendt, Arnold, et al., 1988
CH deform. 1242 s Ar IR Chapman, McIntosh, et al., 1973
Lin and Krantz, 1972
Maier, Hartan, et al., 1976
Masamune, Souto-Bachiller, et al., 1978
Maier, 1988
Orendt, Arnold, et al., 1988
Arnold and Michl, 1993
CH deform. 1237.7 Xe IR Maier and Lautz
Ring deform. 719 w m Ar IR Masamune, Souto-Bachiller, et al., 1978
Maier, 1988
Orendt, Arnold, et al., 1988
Arnold and Michl, 1993
b3g CH stretch 3093 ± 5 Ne Ra Arnold, Radziszewski, et al., 1991
CH stretch 3093 ± 5 Ar Ra Arnold, Radziszewski, et al., 1991
Ring deform. 723 ± 5 Ne Ra Arnold, Radziszewski, et al., 1991
Ring deform. 723 ± 5 Ar Ra Arnold, Radziszewski, et al., 1991
b3u CH OPLA 576 Ne IR Orendt, Arnold, et al., 1988
CH OPLA 569 vs Ar IR Chapman, McIntosh, et al., 1973
Lin and Krantz, 1972
Maier, Hartan, et al., 1976
Masamune, Souto-Bachiller, et al., 1978
Maier, 1988
Orendt, Arnold, et al., 1988
Arnold and Michl, 1993
CH OPLA 573.3 Xe IR Maier and Lautz

Additional references: Jacox, 1994, page 378; Jacox, 1998, page 338; Jacox, 2003, page 355

Notes

wWeak
mMedium
sStrong
vsVery strong

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Vibrational and/or electronic energy levels, Notes

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

Dorofeeva O.V., 1986
Dorofeeva O.V., Thermodynamic properties of twenty-one monocyclic hydrocarbons, J. Phys. Chem. Ref. Data, 1986, 15, 437-464. [all data]

Kohn and Chen, 1993
Kohn, D.W.; Chen, P., Vibrational structure in the photoelectron spectrum of cyclobutadiene as a probe of structure, J. Am. Chem. Soc., 1993, 115, 2844. [all data]

Li and McGee, 1969
Li, P.H.; McGee, H.A., Jr., Mass spectrum and ionization potential of condensed cyclobutadiene, Chem. Commun., 1969, 592. [all data]

Hedaya, Miller, et al., 1969
Hedaya, E.; Miller, R.D.; McNeil, D.W.; D'Angelo, P.F.; Schissel, P., Flash vacuum pyrolysis. V. Cyclobutadiene, J. Am. Chem. Soc., 1969, 91, 1875. [all data]

Dewar and Worley, 1969
Dewar, M.J.S.; Worley, S.D., Photoelectron spectra of molecules. I. Ionization potentials of some organic molecules and their interpretation, J. Chem. Phys., 1969, 50, 654. [all data]

Kreile, Munzel, et al., 1986
Kreile, J.; Munzel, N.; Schweig, A.; Specht, H., UV Photoelectron spectrum of cyclobutadiene. Free cyclobutadiene stable up to high temperatures, Chem. Phys. Lett., 1986, 124, 140. [all data]

Arnold, Radziszewski, et al., 1991
Arnold, B.R.; Radziszewski, J.G.; Campion, A.; Perry, S.S.; Michl, J., The Raman spectrum of matrix-isolated cyclobutadiene. Evidence for environmental hindrance to heavy-atom tunneling?, J. Am. Chem. Soc., 1991, 113, 2, 692, https://doi.org/10.1021/ja00002a058 . [all data]

Maier, 1988
Maier, G., Tetrahedran und Cyclobutadien, Angew. Chem., 1988, 100, 3, 317, https://doi.org/10.1002/ange.19881000304 . [all data]

Orendt, Arnold, et al., 1988
Orendt, A.M.; Arnold, B.R.; Radziszewski, J.G.; Facelli, J.C.; Malsch, K.D.; Strub, H.; Grant, D.M.; Michl, J., Carbon-13 NMR and polarized IR spectra of vicinally labeled cyclobutadiene-13C2 in an argon matrix: interconversion of valence tautomers, J. Am. Chem. Soc., 1988, 110, 8, 2648, https://doi.org/10.1021/ja00216a049 . [all data]

Arnold and Michl, 1993
Arnold, B.R.; Michl, J., Ultraviolet and polarized infrared spectroscopy of matrix-isolated cyclobutadiene and its isotopomers, J. Phys. Chem., 1993, 97, 50, 13348, https://doi.org/10.1021/j100152a046 . [all data]

Masamune, Souto-Bachiller, et al., 1978
Masamune, S.; Souto-Bachiller, F.A.; Machiguchi, T.; Bertie, J.E., Cyclobutadiene is not square, J. Am. Chem. Soc., 1978, 100, 15, 4889, https://doi.org/10.1021/ja00483a043 . [all data]

Chapman, McIntosh, et al., 1973
Chapman, O.L.; McIntosh, C.L.; Pacansky, J., Photochemical transformations. XLVIII. Cyclobutadiene, J. Am. Chem. Soc., 1973, 95, 2, 614, https://doi.org/10.1021/ja00783a066 . [all data]

Lin and Krantz, 1972
Lin, C.Y.; Krantz, A., J. Chem. Soc., 1972, Chem. Commun. 1111. [all data]

Maier, Hartan, et al., 1976
Maier, G.; Hartan, H.-G.; Sayrac, T., Cyclobutadien --- ein quadratisches Singulett-Molekül?, Angew. Chem., 1976, 88, 8, 252, https://doi.org/10.1002/ange.19760880805 . [all data]

Maier and Lautz
Maier, G.; Lautz, C., Eur. J. Org. Chem. 1998, 769.. [all data]

Jacox, 1994
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]

Jacox, 1998
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement A, J. Phys. Chem. Ref. Data, 1998, 27, 2, 115-393, https://doi.org/10.1063/1.556017 . [all data]

Jacox, 2003
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement B, J. Phys. Chem. Ref. Data, 2003, 32, 1, 1-441, https://doi.org/10.1063/1.1497629 . [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Vibrational and/or electronic energy levels, References