Methylene

• Formula: CH₂
• Molecular weight: 14.0266
• IUPAC Standard InChI: InChI=1S/CH2/h1H2 Copy

  
• IUPAC Standard InChIKey: HZVOZRGWRWCICA-UHFFFAOYSA-N Copy
• CAS Registry Number: 2465-56-7
• 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:
  • CD2
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Ion clustering data
  • Vibrational and/or electronic energy levels
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Electron-Impact Ionization Cross Sections (on physics web site)
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Gas phase thermochemistry data

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, References, Notes

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

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 (J/mol*K)
    H° = standard enthalpy (kJ/mol)
    S° = standard entropy (J/mol*K)
    t = temperature (K) / 1000.

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View table.

Reaction 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:
B - John E. Bartmess
RCD - Robert C. Dunbar

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

(CAS Reg. No. 60291-30-7 • 4294967295) +  = CAS Reg. No. 60291-30-7

By formula: (CAS Reg. No. 60291-30-7 • 4294967295CH₂) + CH₂ = CAS Reg. No. 60291-30-7

(CAS Reg. No. 60291-29-4 • 4294967295) +  = CAS Reg. No. 60291-29-4

By formula: (CAS Reg. No. 60291-29-4 • 4294967295CH₂) + CH₂ = CAS Reg. No. 60291-29-4

CH^- +  =

By formula: CH^- + H⁺ = CH₂

(CH₃^- • 4294967295) +  = CH₃^-

By formula: (CH₃^- • 4294967295CH₂) + CH₂ = CH₃^-

 +  = ( • )

By formula: La⁺ + CH₂ = (La⁺ • CH₂)

 +  = ( • )

By formula: Sc⁺ + CH₂ = (Sc⁺ • CH₂)

 +  = ( • )

By formula: Y⁺ + CH₂ = (Y⁺ • CH₂)

 +  = ( • )

By formula: Co⁺ + CH₂ = (Co⁺ • CH₂)

 +  = ( • )

By formula: Cr⁺ + CH₂ = (Cr⁺ • CH₂)

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:
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
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 CH₂⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

De-protonation reactions

CH^- +  =

By formula: CH^- + H⁺ = CH₂

References

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, 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]

Poutsma, Nash, et al., 1997
Poutsma, J.C.; Nash, J.J.; Paulino, J.A.; Squires, R.R., Absolute Heats of Formation of Phenylcarbene and Vinylcarbene, J. Am. Chem. Soc., 1997, 119, 20, 4686, https://doi.org/10.1021/ja963918s . [all data]

Hierl, Henchman, et al., 1992
Hierl, P.M.; Henchman, M.J.; Paulson, J.F., Threshold Energies for the Reactions HO- + MeX - MeOH + X- measured by Tandem Mass Spectrometry: Acidities of MeCl and MeBr, Int. J. Mass Spectrom. Ion Proc., 1992, 117, 475, https://doi.org/10.1016/0168-1176(92)80109-E . [all data]

Ingemann and Nibbering, 1985
Ingemann, S.; Nibbering, N.M.M., Gas phase chemistry of alpha-thio carbanions, Can. J. Chem., 1985, 62, 2273. [all data]

Ingemann and Nibbering, 1985, 2
Ingemann, S.; Nibbering, N.M.M., Gas-phase acidity of CH₃X [X = P(CH₃)₂, SCH₃, F, Cl, Br, I] compounds, J. Chem. Soc. Perkin Trans. 2, 1985, 837. [all data]

Kasdan, Herbst, et al., 1975
Kasdan, A.; Herbst, E.; Lineberger, W.C., Laser photoelectron spectrometry of CH₂^-, Chem. Phys. Lett., 1975, 31, 78. [all data]

Ellison, Engelking, et al., 1978
Ellison, G.B.; Engelking, P.C.; Lineberger, W.C., An experimental determination of the geometry and electron affinity of CH₃, J. Am. Chem. Soc., 1978, 100, 2556. [all data]

Sunderlin and Armentrout, 1989
Sunderlin, L.S.; Armentrout, P.B., Periodic Trends in Chemical Reactivity: Reactions of Sc+, Y+, La+, and Lu+ with Methane and Ethane, J. Am. Chem. Soc., 1989, 111, 11, 3845, https://doi.org/10.1021/ja00193a015 . [all data]

Haynes and Armentrout, 1994
Haynes, C.L.; Armentrout, P.B., Thermochemistry and Structures of CoC3H6+: Metallacyclic and Metal-Alkene Isomers, Organomettalics, 1994, 13, 9, 3480, https://doi.org/10.1021/om00021a022 . [all data]

Georgiadis and Armentrout, 1989
Georgiadis, R.; Armentrout, P.B., Reactions of Ground State Cr+ with C2H6, C2H4, cyclo-C3H6, and cyclo-C2H4O: Bond Energies for CrCHn+ (n= 1-3), Int. J. Mass Spectrom. Ion Proc., 1989, 89, 2-3, 227, https://doi.org/10.1016/0168-1176(89)83062-9 . [all data]

Leopold, Murray, et al., 1985
Leopold, D.G.; Murray, K.K.; Miller, A.E.S.; Lineberger, W.C., Methylene: A study of the X3B1 and the 1A1 states by photoelectron spectroscopy of CH₂^- and CD₂^-, J. Chem. Phys., 1985, 83, 4849. [all data]

Feldman, Rackwitz, et al., 1977
Feldman, D.; Rackwitz, R.; Kaiser, H.J.; Heincke, E., Photodetachment bei einigen neagtiven molekulionen: P₂-, As₂-, CH₂-, CH₃-, S₃-, Z. Naturforsch. A:, 1977, 32, 600. [all data]

Engelking, Corderman, et al., 1981
Engelking, P.E.; Corderman, R.R.; Wenddoski, J.J.; Ellison, G.B.; O'Niel, V.S.; Lineberger, W.C., Laser photoelectron spectroscopy of CH₂-, and the singlet-triplet splitting in methylene, J. Chem. Phys., 1981, 74, 5460. [all data]

Zittel, Ellison, et al., 1976
Zittel, P.F.; Ellison, G.B.; O'Neil, S.V.; Herbst, E.; Lineberger, W.C.; Reinhardt, W.P., Laser photoelectron spectrometry of CH₂^-. Singlet-triplet splitting and electron affinity of CH₂₁, J. Am. Chem. Soc., 1976, 98, 3731. [all data]

Thynne and MacNiel, 1971
Thynne, J.C.J.; MacNiel, K.A.G., Negative ion formation by ethylene and 1,1-difluoroethylene, J. Phys. Chem., 1971, 75, 2584. [all data]

Reineke and Strein, 1976
Reineke, W.; Strein, K., Erzeugung eines methylenhaltigen Molekularstrahls durch Pyrolyse von Keten, Ber. Bunsen-Ges. Phys. Chem., 1976, 80, 343. [all data]

Niehaus, 1967
Niehaus, A., Anregung und Dissoziation von Molekulen beim Elektronenbeschuss. Messung der Bildungswahrscheinlichkeit fur neutrale Fragmente als Funktion der Elektronenenergie., Z. Naturforsch., 1967, 22a, 690. [all data]

Herzberg, 1961
Herzberg, G., The ionization potential of CH₂, Can J. Phys., 1961, 39, 1511. [all data]

Notes

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

• Symbols used in this document:
  

  EA	Electron affinity
  IE (evaluated)	Recommended ionization energy
  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  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

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