Methylene, difluoro-

Formula: CF₂
Molecular weight: 50.0075
IUPAC Standard InChI: InChI=1S/CF2/c2-1-3
IUPAC Standard InChIKey: LTVOKYUPTHZZQH-UHFFFAOYSA-N
CAS Registry Number: 2154-59-8
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Other names: Calcium difluoride; Difluoromethylene
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Gas phase ion energetics data

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Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
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 CF₂⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	11.44 ± 0.03	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	183.	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	175.1	kcal/mol	N/A	Hunter and Lias, 1998	HL

Electron affinity determinations

EA (eV)	Method	Reference	Comment
0.180 ± 0.020	LPES	Schwartz, Davico, et al., 1999	Neutral carbene triplet 54±3 kcal/mol above singlet; B
0.1790 ± 0.0050	LPES	Murray, Leopold, et al., 1988	Singlet-triplet splitting in neutral > 50 kcal/mol; B
0.07 ± 0.15	D-EA	Born, Ingemann, et al., 1994	B
<1.30 ± 0.80	EIAE	Harland and Thynne, 1972	From C2F4. G3MP2B3 calculations indicate an EA of ca. 0.4 eV.; B
>0.20047	EIAE	Thynne and MacNeil, 1970	From C2F4. G3MP2B3 calculations indicate an EA of ca. 0.4 eV.; B
2.64955	SI	Page and Goode, 1969	The Magnetron method, lacking mass analysis, is not considered reliable.; B

Ionization energy determinations

IE (eV)	Method	Reference	Comment
11.445 ± 0.025	PI	Buckley, Johnson, et al., 1995	LL
15.2	EI	Goto, Nakamura, et al., 1994	LL
11.5 ± 0.4	EI	Tarnovsky and Becker, 1993	LL
11.4 ± 0.3	EI	Hildenbrand, 1975	LLK
11.5 ± 0.1	EI	Hildenbrand, 1975	LLK
11.42 ± 0.01	PE	Dyke, Golob, et al., 1974	LLK
9.74	DER	Reinke, Kraessig, et al., 1973	LLK
11.54 ± 0.10	EI	Hildenbrand, 1973	LLK
11.7 ± 0.2	EI	Ehlert, 1969	RDSH
11.8 ± 0.3	EI	Zmbov, Uy, et al., 1968	RDSH
11.9 ± 0.1	EI	Pottie, 1965	RDSH
11.7 ± 0.1	EI	Fisher, Homer, et al., 1965	RDSH

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
CF⁺	18.5	F	EI	Goto, Nakamura, et al., 1994	LL
CF⁺	14.6 ± 0.4	F	EI	Tarnovsky, Kurunczi, et al., 1993	LL
F⁺	31.4 ± 1.0	CF⁺	EI	Tarnovsky, Kurunczi, et al., 1993	LL

References

Go To: Top, Gas phase ion energetics data, Notes

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Schwartz, Davico, et al., 1999
Schwartz, R.L.; Davico, G.E.; Ramond, T.M.; Lineberger, W.C., Singlet-triplet splittings in CX2 (X = F, Cl, Br, I) dihalocarbenes via negative ion photoelectron spectroscopy, J. Phys. Chem. A, 1999, 103, 41, 8213-8221, https://doi.org/10.1021/jp992214c . [all data]

Murray, Leopold, et al., 1988
Murray, K.K.; Leopold, D.G.; Miller, T.M.; Lineberger, W.C., Photoelectron Spectroscopy of the Halocarbene Anions HCF^-, HCCl^-, HCBr^-, HCI^-, CF₂^-, and CCl₂^-, J. Chem. Phys., 1988, 89, 9, 5442, https://doi.org/10.1063/1.455596 . [all data]

Born, Ingemann, et al., 1994
Born, M.; Ingemann, S.; Nibbering, N.M.M., Heats of formation of mono-halogen-substituted carbenes. Stability and reactivity of CHX(center dot-) (X=F, Cl, Pr, and I) radical anions, J. Am. Chem. Soc., 1994, 116, 16, 7210, https://doi.org/10.1021/ja00095a025 . [all data]

Harland and Thynne, 1972
Harland, P.W.; Thynne, J.C.J., Ionisation of perfluorocyclobutane by electron impact, Int. J. Mass Spectrom. Ion Phys., 1972, 10, 11. [all data]

Thynne and MacNeil, 1970
Thynne, J.C.J.; MacNeil, K.A.G., Ionisation of Tetrafluoroethylene by Electron Impact, Int. J. Mass Spectrom. Ion Phys., 1970, 5, 3-4, 329, https://doi.org/10.1016/0020-7381(70)80026-2 . [all data]

Page and Goode, 1969
Page, F.M.; Goode, G.C., Negative Ions and the Magnetron., Wiley, NY, 1969. [all data]

Buckley, Johnson, et al., 1995
Buckley, T.J.; Johnson, R.D.; Huie, R.E.; Zhang, Z.; Kuo, S.C.; Klemm, R.B., Ionization energies, appearance energies, and thermochemistry of CF₂O and FCO, J. Phys. Chem., 1995, 99, 4879. [all data]

Goto, Nakamura, et al., 1994
Goto, M.; Nakamura, K.; Toyoda, H.; Sugai, H., Cross section measurements for electron-impact dissociation of CHF₃ into neutral and ionic fragments, Jpn. J. Appl. Phys. Part 1, 1994, 33, 3602. [all data]

Tarnovsky and Becker, 1993
Tarnovsky, V.; Becker, K., Absolute partial cross sections for the parent ionization of the CF_x (x = 1-3) free radicals by electron impact, J. Chem. Phys., 1993, 98, 7868. [all data]

Hildenbrand, 1975
Hildenbrand, D.L., Vertical ionization potential of the CF₂ radical, Chem. Phys. Lett., 1975, 32, 30. [all data]

Dyke, Golob, et al., 1974
Dyke, J.M.; Golob, L.; Jonathan, N.; Morris, A.; Okuda, M., Vacuum ultraviolet photoelectron spectroscopy of transient species. Part 4. Difluoromethylene and ozone, J. Chem. Soc. Faraday Trans. 2, 1974, 70, 1828. [all data]

Reinke, Kraessig, et al., 1973
Reinke, D.; Kraessig, R.; Baumgartel, H., Photoreactions of small organic molecules, Z. Naturforsch. A:, 1973, 28, 1021. [all data]

Hildenbrand, 1973
Hildenbrand, D.L., Mass spectrometric studies of some gaseous sulfur fluorides, J. Phys. Chem., 1973, 77, 897. [all data]

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

Zmbov, Uy, et al., 1968
Zmbov, K.F.; Uy, M.; Margrave, J.L., Mass spectrometric study of the high-temperature equilibrium C₂F₄ = 2CF₂ and the heat of formation of the CF₂ radical, J. Am. Chem. Soc., 1968, 90, 5090. [all data]

Pottie, 1965
Pottie, R.F., Ionization potential and heat of formation of the difluoromethylene radical, J. Chem. Phys., 1965, 42, 2607. [all data]

Fisher, Homer, et al., 1965
Fisher, I.P.; Homer, J.B.; Lossing, F.P., Free radicals by mass spectrometry. XXXIII. Ionization potentials of CF₂, CF₃CF₂, CF₃CH₂, n-C₃F₇, and i-C₃F₇ radicals, J. Am. Chem. Soc., 1965, 87, 957. [all data]

Tarnovsky, Kurunczi, et al., 1993
Tarnovsky, V.; Kurunczi, P.; Rogozhnikov, D.; Becker, K., Absolute cross sections for the dissociative electron impact ionization of the CFx (x=1-3) free radicals, Int. J. Mass Spectrom. Ion Processes, 1993, 128, 181. [all data]

Notes

Go To: Top, Gas phase ion energetics data, References

Symbols used in this document:

AE Appearance energy

EA Electron affinity

IE (evaluated) Recommended ionization energy
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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AE	Appearance energy
EA	Electron affinity
IE (evaluated)	Recommended ionization energy