Ethyne, difluoro-

Formula: C₂F₂
Molecular weight: 62.0182
IUPAC Standard InChI: InChI=1S/C2F2/c3-1-2-4
IUPAC Standard InChIKey: BWTZYYGAOGUPFQ-UHFFFAOYSA-N
CAS Registry Number: 689-99-6
Chemical structure:
This structure is also available as a 2d Mol file
Other names: Acetylene, difluoro-; Difluoroacetylene; FC≡CF; Difluoroethyne; C2F2
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Information on this page:
Other data available:
- Gas phase thermochemistry data
- Mass spectrum (electron ionization)
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Gas phase ion energetics data

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Data compiled as indicated in comments:
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C₂F₂⁺ (ion structure unspecified)

Ionization energy determinations

IE (eV)	Method	Reference	Comment
11.18	PE	Bieri, Schmelzer, et al., 1980	LLK
11.18	PE	Bieri, Heilbronner, et al., 1977	LLK
11.4 ± 0.5	EI	Ehlert, 1969	RDSH

Vibrational and/or electronic energy levels

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Data compiled by: Marilyn E. Jacox

State: X

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


Σ_g⁺	1	CC stretch	2436	T	gas	IR	Burger, Schneider, et al., 1991 McNaughton and Elmes, 1992
	2	CF s-stretch	787	T	gas	IR	Burger, Schneider, et al., 1991 McNaughton and Elmes, 1992
Σ_u⁺	3	CF a-stretch	1349.524		gas	IR	Burger, Schneider, et al., 1991 Burger and Sommer, 1992 McNaughton and Elmes, 1992
	3	CF a-stretch	1346.9	vs	Ne	IR	Burger, Schneider, et al., 1991
	3	CF a-stretch	1340.7	vs	Ar	IR	Brahms and Dailey, 1989 Burger, Schneider, et al., 1991
Π_g	4	Bend	270	T	gas	IR	Burger, Schneider, et al., 1991 McNaughton and Elmes, 1992
Π_u	5	Bend	268	T	gas	IR	McNaughton and Elmes, 1992
	5	Bend	286.7	w	Ar	IR	Burger, Schneider, et al., 1991
	5	Bend	279.3	w	Ar	IR	Burger, Schneider, et al., 1991

Additional references: Jacox, 1994, page 197

Notes

Weak

Very strong

Tentative assignment or approximate value

References

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

Bieri, Schmelzer, et al., 1980
Bieri, G.; Schmelzer, A.; Asbrink, L.; Jonsson, M., Fluorine and the fluoroderivatives of acetylene and diacetylene studied by 30.4 nm He(II) photoelectron spectroscopy, Chem. Phys., 1980, 49, 213. [all data]

Bieri, Heilbronner, et al., 1977
Bieri, G.; Heilbronner, E.; Stadelmann, J.-P.; Vogt, J.; von Niessen, W., Electronic states of difluoroacetylene, difluorodiacetylene, and perfluoropentadiyne-1,3 radical cations. A photoelectron spectroscopic investigation, J. Am. Chem. Soc., 1977, 99, 6832. [all data]

Ehlert, 1969
Ehlert, T.C., Bonding in C₁ and C₂ fluorides, J. Phys. Chem., 1969, 73, 949. [all data]

Burger, Schneider, et al., 1991
Burger, H.; Schneider, W.; Sommer, S.; Thiel, W.; Willner, H., The vibrational spectrum and rotational constants of difluoroethyne FC 3/4 CF. Matrix and high resolution infrared studies and ab initio calculations, J. Chem. Phys., 1991, 95, 8, 5660, https://doi.org/10.1063/1.461640 . [all data]

McNaughton and Elmes, 1992
McNaughton, D.; Elmes, P., Spectrochim. Acta, 1992, 48A, 605. [all data]

Burger and Sommer, 1992
Burger, H.; Sommer, S., The high-resolution infrared spectrum of FC«58876»CF: The 1350 and 2150 cm-1 regions, J. Mol. Spectrosc., 1992, 151, 1, 148, https://doi.org/10.1016/0022-2852(92)90011-C . [all data]

Brahms and Dailey, 1989
Brahms, J.C.; Dailey, W.P., Difluoromaleic anhydride as a source of matrix isolated difluoropropadienone, difluorocyclopropenone and difluoroacetylene, J. Am. Chem. Soc., 1989, 111, 24, 8940, https://doi.org/10.1021/ja00206a039 . [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]

Notes

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Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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