Formaldehyde

• Formula: CH₂O
• Molecular weight: 30.0260
• IUPAC Standard InChI: InChI=1S/CH2O/c1-2/h1H2 Copy

  
• IUPAC Standard InChIKey: WSFSSNUMVMOOMR-UHFFFAOYSA-N Copy
• 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:
  • Gas phase thermochemistry data
  • Gas phase ion energetics data
  • Ion clustering data
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Phase change data
  • Reaction thermochemistry data
  • IR Spectrum
  • Vibrational and/or electronic energy levels
  • Gas Chromatography
• Data at other public NIST sites:
  • Electron-Impact Ionization Cross Sections (on physics web site)
  • Gas Phase Kinetics Database
  • X-ray Photoelectron Spectroscopy Database, version 5.0
• Options:
  • Switch to SI units

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• NIST / TRC Web Thermo Tables, "lite" edition (thermophysical and thermochemical data)
• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

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Gas phase thermochemistry data

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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:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Constant pressure heat capacity of gas

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
    C_p = heat capacity (cal/mol*K)
    H° = standard enthalpy (kcal/mol)
    S° = standard entropy (cal/mol*K)
    t = temperature (K) / 1000.

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Gas phase ion energetics data

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

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)

Proton affinity at 298K

Gas basicity at 298K

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

CHO^- +  =

By formula: CHO^- + H⁺ = CH₂O

Ion clustering data

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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:
RCD - Robert C. Dunbar
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
B - John E. Bartmess

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

 +  = ( • )

By formula: Al⁺ + CH₂O = (Al⁺ • CH₂O)

CH₂N⁺ +  = (CH₂N⁺ • )

By formula: CH₂N⁺ + CH₂O = (CH₂N⁺ • CH₂O)

Bond type: Hydrogen bonds of the type NH+-O between organics

 +  = ( • )

By formula: CH₃O⁺ + CH₂O = (CH₃O⁺ • CH₂O)

Bond type: Hydrogen bonds of the type OH-O between organics

(CH₃O^- • 4294967295) +  = CH₃O^-

By formula: (CH₃O^- • 4294967295CH₂O) + CH₂O = CH₃O^-

 +  = ( • )

By formula: Fe⁺ + CH₂O = (Fe⁺ • CH₂O)

( • ) +  = ( • 2)

By formula: (Fe⁺ • CH₂O) + CH₂O = (Fe⁺ • 2CH₂O)

( • 2) +  = ( • 3)

By formula: (Fe⁺ • 2CH₂O) + CH₂O = (Fe⁺ • 3CH₂O)

( • 3) +  = ( • 4)

By formula: (Fe⁺ • 3CH₂O) + CH₂O = (Fe⁺ • 4CH₂O)

 +  = ( • )

By formula: Li⁺ + CH₂O = (Li⁺ • CH₂O)

Mass spectrum (electron ionization)

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

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

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Additional Data

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), Notes

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

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Fletcher and Pilcher, 1970
Fletcher, R.A.; Pilcher, G., Measurements of heats of combustion by flame calorimetry, Trans. Faraday Soc., 1970, 66, 794-799. [all data]

Wartenberg and Lerner-Steinberg, 1925
Wartenberg, H.; Lerner-Steinberg, Heat of formation of formaldehyde, Z. Angew. Chem., 1925, 38, 591-592. [all data]

Thermodynamics Research Center, 1997
Thermodynamics Research Center, Selected Values of Properties of Chemical Compounds., Thermodynamics Research Center, Texas A&M University, College Station, Texas, 1997. [all data]

Thompson, 1941
Thompson, H.W., Thermodynamic functions and equilibria of formaldehyde, deuteroformaldehyde, phosgene and thiophosgene, Trans. Faraday Soc., 1941, 37, 251-260. [all data]

Pillai M.G.K., 1961
Pillai M.G.K., Potential energy constants, rotational distortion constants, and calculated thermodynamic properties for some planar XYZ2 molecules, J. Mol. Spectrosc., 1961, 6, 465-471. [all data]

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Chao J., 1980
Chao J., Perfect gas thermodynamic properties of methanal, ethanal and their deuterated species, Thermochim. Acta, 1980, 41, 41-54. [all data]

Chao J., 1986
Chao J., Thermodynamic properties of key organic oxygen compounds in the carbon range C1 to C4. Part 2. Ideal gas properties, J. Phys. Chem. Ref. Data, 1986, 15, 1369-1436. [all data]

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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]

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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]

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Hernandez, Masclet, et al., 1977
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Drury-Lessard and Moule, 1977
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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]

Bouchard, Brenner, et al., 1997
Bouchard, F.; Brenner, V.; Carra, C.; Hepburn, J.W.; Koyanagi, G.K.; McMahon, T.B.; Ohanessian, G.; Peschke, M., Energetics and Structure of Complexes of Al+ with Small Organic Molecules in the Gas Phase, J. Phys. Chem. A, 1997, 101, 33, 5885, https://doi.org/10.1021/jp9703465 . [all data]

Tanaka, Mackay, et al., 1978
Tanaka, K.; Mackay, G.I.; Bohme, D.K., Rate and Equilibrium Constant Measurements for Gas-Phase Proton-Transfer Reactions Involving H2O, H2S, HCN, and H2CO, Can. J. Chem., 1978, 56, 2, 193, https://doi.org/10.1139/v78-031 . [all data]

Meot-Ner (Mautner), 1978
Meot-Ner (Mautner), M., Solvation of the Proton by HCN and CH3CN. Condensation of HCN with Ions in the Gas Phase., J. Am. Chem. Soc., 1978, 100, 15, 4694, https://doi.org/10.1021/ja00483a012 . [all data]

Larson and McMahon, 1982
Larson, J.W.; McMahon, T.B., Formation, Thermochemistry, and Relative Stabilities of Proton - Bound dimers of Oxygen n - Donor Bases from Ion Cyclotron Resonance Solvent - Exchange Equilibria Measurements, J. Am. Chem. Soc., 1982, 104, 23, 6255, https://doi.org/10.1021/ja00387a016 . [all data]

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Cunningham, A.J.; Payzant, J.D.; Kebarle, P., A Kinetic Study of the Proton Hydrate H+(H2O)n Equilibria in the Gas Phase, J. Am. Chem. Soc., 1972, 94, 22, 7627, https://doi.org/10.1021/ja00777a003 . [all data]

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Fehsenfeld, F.C.; Dotan, I.; Albritton, D.L.; Howard, C.J.; Ferguson, E.E., Stratospheric Positive Ion Chemistry of Formaldehyde and Methanol, J. Geophys. Res., 1978, 83, C3, 1333, https://doi.org/10.1029/JC083iC03p01333 . [all data]

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Nee, Osterwalder, et al., 2006
Nee, M.J.; Osterwalder, A.; Zhou, J.; Neumark, D.M., Slow electron velocity-map imaging photoelectron spectra of the methoxide anion, J. Chem. Phys., 2006, 125, 1, 014306, https://doi.org/10.1063/1.2212411 . [all data]

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Osborn, D.L.; Leahy, D.J.; Kim, E.H.; deBeer, E.; Neumark, D.M., Photoelectron spectroscopy of CH3O- and CD3O-, Chem. Phys. Lett., 1998, 292, 4-6, 651-655, https://doi.org/10.1016/S0009-2614(98)00717-9 . [all data]

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Staley and Beauchamp, 1975
Staley, R.H.; Beauchamp, J.L., Intrinsic Acid - Base Properties of Molecules. Binding Energies of Li+ to pi - and n - Donor Bases, J. Am. Chem. Soc., 1975, 97, 20, 5920, https://doi.org/10.1021/ja00853a050 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), References

• Symbols used in this document:
  

  AE	Appearance energy
  Cp,gas	Constant pressure heat capacity of gas
  IE (evaluated)	Recommended ionization energy
  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  ΔcH°gas	Enthalpy of combustion of gas at standard conditions
  ΔfH(+) ion,0K	Enthalpy of formation of positive ion at 0K
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔrS°	Entropy of reaction at standard conditions

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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