m-Benzyne

Formula: C₆H₄
Molecular weight: 76.0960
CAS Registry Number: 1828-89-3
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Other data available:
- Gas phase thermochemistry data
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Gas phase ion energetics data

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View reactions leading to C₆H₄⁺ (ion structure unspecified)

Electron affinity determinations

EA (eV)	Method	Reference	Comment
0.846 ± 0.013	CIDT	Wenthold, Hu, et al., 1996	Triplet state 21.0±0.3 kcal/mol up.
<0.990003	LPES	Wenthold, Squires, et al., 1998

Vibrational and/or electronic energy levels

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Data compiled by: Marilyn E. Jacox

State: a

Energy (cm^-1)	Med.	References


T_o = 7350 ± 110	gas	Wenthold, Squires, et al., 1998, 2

Vib. sym.	cm^-1	Med.	Method	References


a₁	970 ± 15	gas	PE	Wenthold, Squires, et al., 1998, 2

State: X

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


a₁	1	CH stretch	3037	w	Ar	IR	Marquardt, Sander, et al., 1996
	4	Mixed	1402	w m	Ar	IR	Marquardt, Sander, et al., 1996 Sander, Exner, et al., 2002
	9	Ring deform.	300	T	gas	PE	Wenthold, Squires, et al., 1998, 2
	9	Ring deform.	367	T	Ar	IR	Sander, Exner, et al., 2002
b₁	13	CH OPLA	824	w m	Ar	IR	Marquardt, Sander, et al., 1996 Sander, Exner, et al., 2002
	14	CH OPLA	751	m s	Ar	IR	Marquardt, Sander, et al., 1996 Sander, Exner, et al., 2002
	15	Ring deform.	561	w m	Ar	IR	Sander, Exner, et al., 2002
	16	Ring deform.	362	T	Ar	IR	Sander, Exner, et al., 2002
b₂	18	Mixed	1486	w m	Ar	IR	Marquardt, Sander, et al., 1996 Sander, Exner, et al., 2002
	23	HCC deform.	936	m	Ar	IR	Marquardt, Sander, et al., 1996 Sander, Exner, et al., 2002
	24	Ring deform.	547	vs	Ar	IR	Marquardt, Sander, et al., 1996 Sander, Exner, et al., 2002

Additional references: Jacox, 1998, page 346; Jacox, 2003, page 365

Notes

Weak

Medium

Strong

Very strong

Tentative assignment or approximate value

Energy separation between the v = 0 levels of the excited and electronic ground states.

References

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

Wenthold, Hu, et al., 1996
Wenthold, P.G.; Hu, J.; Squires, R.R., o-, m-, and p-Benzyne Negative Ions in the Gas Phase: Synthesis, Authentication, and Thermochemistry, J. Am. Chem. Soc., 1996, 118, 47, 11865, https://doi.org/10.1021/ja960663+ . [all data]

Wenthold, Squires, et al., 1998
Wenthold, P.G.; Squires, R.R.; Lineberger, W.C., Ultraviolet photoelectron spectroscopy of the o-, m-, and p-benzyne negative ions. Electron affinities and singlet-triplet splittings for o-, m-, and p-benzyne, J. Am. Chem. Soc., 1998, 120, 21, 5279-5290, https://doi.org/10.1021/ja9803355 . [all data]

Wenthold, Squires, et al., 1998, 2
Wenthold, P.G.; Squires, R.R.; Lineberger, W.C., Ultraviolet Photoelectron Spectroscopy of the, J. Am. Chem. Soc., 1998, 120, 21, 5279, https://doi.org/10.1021/ja9803355 . [all data]

Marquardt, Sander, et al., 1996
Marquardt, R.; Sander, W.; Kraka, E., 1, 3-Didehydrobenzol (meta-Benzin), Angew. Chem., 1996, 108, 7, 825, https://doi.org/10.1002/ange.19961080719 . [all data]

Sander, Exner, et al., 2002
Sander, W.; Exner, M.; Winkler, M.; Balster, A.; Hjerpe, A.; Kraka, E.; Cremer, D., Vibrational Spectrum of, J. Am. Chem. Soc., 2002, 124, 44, 13072, https://doi.org/10.1021/ja012686g . [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

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Symbols used in this document:

EA Electron affinity
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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