Formaldehyde

Formula: CH₂O
Molecular weight: 30.0260
IUPAC Standard InChI: InChI=1S/CH2O/c1-2/h1H2
IUPAC Standard InChIKey: WSFSSNUMVMOOMR-UHFFFAOYSA-N
CAS Registry Number: 50-00-0
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.
Isotopologues:
- methanal-d
Other names: Methanal; BFV; Fannoform; Formaldehyde, gas; Formalin; Formalith; Formic aldehyde; Formol; Fyde; Lysoform; Methyl aldehyde; Methylene oxide; Morbicid; Oxomethane; Oxymethylene; Paraform; Superlysoform; Karsan; Methaldehyde; Aldehyde formique; Aldeide formica; Formaldehyd; Formalin-loesungen; Formalina; Formaline; NCI-C02799; Oplossingen; Aldehyd mravenci; Formalin 40; Rcra waste number U122; UN 1198; UN 2209; H2CO; Durine; Hercules 37M6-8; CH2O; NSC 298885; Fordor
Permanent link for this species. Use this link for bookmarking this species for future reference.
Information on this page:
Other data available:
Data at other public NIST sites:
Options:
- Switch to calorie-based units

Data at NIST subscription sites:

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 ion energetics data

Go To: Top, References, Notes

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

Data compiled as indicated in comments:
B - John E. Bartmess
MM - Michael M. Meot-Ner (Mautner)
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
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 CH₂O⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	10.88 ± 0.01	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	712.9	kJ/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	683.3	kJ/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_{(+) ion}	941.8	kJ/mol	N/A	N/A
Quantity	Value	Units	Method	Reference	Comment
Δ_fH_{(+) ion,0K}	946.0	kJ/mol	N/A	N/A

Proton affinity at 298K

Proton affinity (kJ/mol)	Reference	Comment
711.5 ± 2.1	Bouchoux and Leblanc, 2000	T = 300K; MM

Gas basicity at 298K

Gas basicity (review) (kJ/mol)	Reference	Comment
681.5 ± 0.7	Bouchoux and Leblanc, 2000	T = 300K; MM

Ionization energy determinations

IE (eV)	Method	Reference	Comment
10.88	CI	Ohno, Okamura, et al., 1995	LL
10.8887 ± 0.0030	PE	Niu, Shirley, et al., 1993	LL
10.86	PI	Traeger, 1985	LBLHLM
10.88	PE	Kimura, Katsumata, et al., 1981	LLK
10.9	PE	Von Niessen, Bieri, et al., 1980	LLK
10.885 ± 0.005	PE	Hernandez, Masclet, et al., 1977	LLK
10.874 ± 0.002	S	Drury-Lessard and Moule, 1977	LLK
10.868 ± 0.005	PI	Guyon, Chupka, et al., 1976	LLK
10.88 ± 0.02	PI	Warneck, 1971	LLK
10.87 ± 0.01	PI	Mentall, Gentieu, et al., 1971	LLK
10.88 ± 0.02	PI	Matthews and Warneck, 1969	RDSH
10.884	PE	Baker, Baker, et al., 1968	RDSH
10.86 ± 0.02	EI	Kanomata, 1961	RDSH
10.90 ± 0.03	PI	Vilesov, 1960	RDSH
10.87 ± 0.01	PI	Watanabe, 1957	RDSH
10.88 ± 0.01	S	Price, 1935	RDSH
10.1	PE	Rao, 1975	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
CHO⁺	11.97	H	PI	Traeger, 1985	LBLHLM
CHO⁺	13.94 ± 0.40	H	EI	Wankenne, Caprace, et al., 1984	LBLHLM
CHO⁺	11.92 ± 0.01	H	PI	Guyon, Chupka, et al., 1976	LLK
CHO⁺	11.89 ± 0.03	H	PI	Warneck, 1971	LLK
CHO⁺	11.95 ± 0.06	H	PI	Matthews and Warneck, 1969	RDSH
CO⁺	14.10 ± 0.08	H₂	PI	Guyon, Chupka, et al., 1976	LLK
CO⁺	18.7 ± 0.2	?	EI	Brand and Reed, 1957	RDSH
H⁺	17.41 ± 0.07	CHO	PI	Warneck, 1971	LLK
H₂⁺	15.42 ± 0.06	CO	PI	Warneck, 1971	LLK

De-protonation reactions

CHO^- + = Formaldehyde

By formula: CHO^- + H⁺ = CH₂O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1650.7 ± 0.96	kJ/mol	D-EA	Murray, Miller, et al., 1986	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1617.7 ± 1.7	kJ/mol	H-TS	Murray, Miller, et al., 1986	gas phase; B
Δ_rG°	1648. ± 19.	kJ/mol	IMRB	Karpas and Klein, 1975	gas phase; B

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]

Bouchoux and Leblanc, 2000
Bouchoux, G.; Leblanc, D., Gas-phase basicity of formaldehyde by the thermokinetic method, European J. Mass Spectrom., 2000, 6, 443. [all data]

Ohno, Okamura, et al., 1995
Ohno, K.; Okamura, K.; Yamakado, H.; Hoshino, S.; Takami, T.; Yamauchi, M., Penning ionization of HCHO, CH₂CH₂, and CH₂CHCHO by collision with He*(2 3S) metastable atoms, J. Phys. Chem., 1995, 99, 14247. [all data]

Niu, Shirley, et al., 1993
Niu, B.; Shirley, D.A.; Bai, Y., High resolution photoelectron spectroscopy and femtosecond intramolecular dynamics of H₂CO⁺ and D₂CO⁺, J. Chem. Phys., 1993, 98, 4377. [all data]

Traeger, 1985
Traeger, J.C., Heat of formation for the formyl cation by photoionization mass spectrometry, Int. J. Mass Spectrom. Ion Processes, 1985, 66, 271. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Von Niessen, Bieri, et al., 1980
Von Niessen, W.; Bieri, G.; Asbrink, L., 30.4 nm He(II) photoelectron spectra of organic molecules. Part III. Oxo-compounds (C,H,O), J. Electron Spectrosc. Relat. Phenom., 1980, 21, 175. [all data]

Hernandez, Masclet, et al., 1977
Hernandez, R.; Masclet, P.; Mouvier, G., Spectroscopie de photoelectrons d'aldehydes et de cetones aliphatiques, J. Electron Spectrosc. Relat. Phenom., 1977, 10, 333. [all data]

Drury-Lessard and Moule, 1977
Drury-Lessard, C.R.; Moule, D.C., The higher Rydberg states of formaldehyde, Chem. Phys. Lett., 1977, 47, 300. [all data]

Guyon, Chupka, et al., 1976
Guyon, P.M.; Chupka, W.A.; Berkowitz, J., Photoionization mass spectrometric study of formaldehyde H₂CO, HDCO, and D₂CO, J. Chem. Phys., 1976, 65, 1419. [all data]

Warneck, 1971
Warneck, P., Photoionisation von methanol und formaldehyd, Z. Naturforsch. A:, 1971, 26, 2047. [all data]

Mentall, Gentieu, et al., 1971
Mentall, J.E.; Gentieu, E.P.; Krauss, M.; Neumann, D., Photoionization and absorption spectrum of formaldehyde in the vacuum ultraviolet, J. Chem. Phys., 1971, 55, 5471. [all data]

Matthews and Warneck, 1969
Matthews, C.S.; Warneck, P., Heats of formation of CHO⁺ and C₃H₃⁺ by photoionization, J. Chem. Phys. 5, 1969, 1, 854. [all data]

Baker, Baker, et al., 1968
Baker, A.D.; Baker, C.; Brundle, C.R.; Turner, D.W., The electronic structures of methane, ethane, ethylene and formaldehyde studied by high-resolution molecular photoelectron spectroscopy, Intern. J. Mass Spectrom. Ion Phys., 1968, 1, 285. [all data]

Kanomata, 1961
Kanomata, I., Mass-spectrometric study on ionization and dissociation of formaldehyde, acetaldehyde, acetone and ethyl methyl ketone by electron impact, Bull. Chem. Soc. Japan, 1961, 34, 1864. [all data]

Vilesov, 1960
Vilesov, F.I., The photoionization of vapors of compounds whose molecules contain carbonyl groups, Dokl. Phys. Chem., 1960, 132, 521, In original 1332. [all data]

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Price, 1935
Price, W.C., The far ultraviolet absorption spectra of formaldehyde and the alkyl derivatives of H, O and H₂S, J. Chem. Phys., 1935, 3, 256. [all data]

Rao, 1975
Rao, C.N.R., Lone-pair ionization bands of chromophores in the photoelectron spectra of organic molecules, Indian J. Chem., 1975, 13, 950. [all data]

Wankenne, Caprace, et al., 1984
Wankenne, H.; Caprace, G.; Momigny, J., Unimolecular decay of metastable ions in formaldehyde, Int. J. Mass Spectrom. Ion Processes, 1984, 57, 149. [all data]

Brand and Reed, 1957
Brand, J.C.D.; Reed, R.I., The electronic spectrum of formaldehyde. Part II. Mechanisms of dissociation of formaldehyde and the formaldehyde molecular ion, J. Chem. Soc., 1957, 2386. [all data]

Murray, Miller, et al., 1986
Murray, K.K.; Miller, T.M.; Leopold, D.G.; Lineberger, W.C., Laser photoelectron spectroscopy of the Formylf anion, J. Chem. Phys., 1986, 84, 2520. [all data]

Karpas and Klein, 1975
Karpas, Z.; Klein, F.S., Negative ion-molecule reactions in a mixture of ammonia-formaldehyde - an ICR mass spectrometry study, Int. J. Mass Spectrom. Ion Phys., 1975, 18, 65. [all data]

Notes

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

Symbols used in this document:

AE	Appearance energy
IE (evaluated)	Recommended ionization energy
Δ_fH_{(+) ion,0K}	Enthalpy of formation of positive ion at 0K
Δ_rG°	Free energy of reaction at standard conditions
Δ_rH°	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.