Methane, diazo-

Formula: CH₂N₂
Molecular weight: 42.0400
IUPAC Standard InChI: InChI=1S/CH2N2/c1-3-2/h1H2
IUPAC Standard InChIKey: YXHKONLOYHBTNS-UHFFFAOYSA-N
CAS Registry Number: 334-88-3
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.
Other names: Azimethylene; Diazomethane; Acomethylene; Diazirine; Diazonium methylide
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Information on this page:
Other data available:
- Mass spectrum (electron ionization)
- UV/Visible spectrum
Data at other public NIST sites:
- Gas Phase Kinetics Database
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Gas phase thermochemistry data

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Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	51.3	kcal/mol	Kin	Laufer and Okabe, 1971	Heat of formation at 0 K
Δ_fH°_gas	49.3 ± 2.3	kcal/mol	Ion	Paulett and Ettinger, 1963	Mass spectra

Reaction thermochemistry data

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Data compiled by: John E. Bartmess

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Individual Reactions

CHN₂^- + = Methane, diazo-

By formula: CHN₂^- + H⁺ = CH₂N₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	371.4 ± 2.2	kcal/mol	G+TS	Clifford, Wenthold, et al., 1998	gas phase; Lit values of DfH(H2CNN) range from 71 (78BEN) to 51 ( Laufer and Okabe, 1972). Here we use the computational ( Dixon, de Jong, et al., 2005) agreeing with G3MP2B3
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	364.1 ± 2.0	kcal/mol	IMRE	Clifford, Wenthold, et al., 1998	gas phase; Lit values of DfH(H2CNN) range from 71 (78BEN) to 51 ( Laufer and Okabe, 1972). Here we use the computational ( Dixon, de Jong, et al., 2005) agreeing with G3MP2B3
Δ_rG°	365.0 ± 4.0	kcal/mol	IMRB	DePuy, Van Doren, et al., 1989	gas phase; Near HF, between H2O2 & acetone. G2 calculations( Gordon and Kass, 1997) give ΔHf(CH2N2)=63.1 kcal/mol

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:
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 CH₂N₂⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	8.999 ± 0.001	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	205.3	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	197.6	kcal/mol	N/A	Hunter and Lias, 1998	HL

Ionization energy determinations

IE (eV)	Method	Reference	Comment
9.00	PE	Bastide and Maier, 1976	LLK
8.999 ± 0.001	S	Merer, 1964	RDSH
9.03 ± 0.05	EI	Paulett and Ettinger, 1963, 2	RDSH
9.2 ± 0.3	EI	Berkowitz and Wexler, 1962	RDSH

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
CHN₂⁺	14.8 ± 0.1	H	EI	Paulett and Ettinger, 1963, 2	RDSH
CH₂⁺	12.3 ± 0.1	N₂	EI	Paulett and Ettinger, 1963, 2	RDSH

De-protonation reactions

CHN₂^- + = Methane, diazo-

By formula: CHN₂^- + H⁺ = CH₂N₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	371.4 ± 2.2	kcal/mol	G+TS	Clifford, Wenthold, et al., 1998	gas phase; Lit values of DfH(H2CNN) range from 71 (78BEN) to 51 ( Laufer and Okabe, 1972). Here we use the computational ( Dixon, de Jong, et al., 2005) agreeing with G3MP2B3; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	364.1 ± 2.0	kcal/mol	IMRE	Clifford, Wenthold, et al., 1998	gas phase; Lit values of DfH(H2CNN) range from 71 (78BEN) to 51 ( Laufer and Okabe, 1972). Here we use the computational ( Dixon, de Jong, et al., 2005) agreeing with G3MP2B3; B
Δ_rG°	365.0 ± 4.0	kcal/mol	IMRB	DePuy, Van Doren, et al., 1989	gas phase; Near HF, between H2O2 & acetone. G2 calculations( Gordon and Kass, 1997) give ΔHf(CH2N2)=63.1 kcal/mol; B

References

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Laufer and Okabe, 1971
Laufer, A.H.; Okabe, H., Heat of formation and bond dissociation energy of diazomethane by a photodissociation method, J. Am. Chem. Soc., 1971, 93, 4137-7140. [all data]

Paulett and Ettinger, 1963
Paulett, G.S.; Ettinger, R., Mass spectra and appearance potentials of diazirine and diazomethane, J. Chem. Phys., 1963, 39, 825-827. [all data]

Clifford, Wenthold, et al., 1998
Clifford, E.P.; Wenthold, P.G.; Lineberger, W.C.; Peterssom, G.A.; Broaddus, K.M.; Kass, S.R.; Kato, S., Properties of Diazocarbene [CNN] and the diazomethyl Radical [HCNN] via Ion Chemistry and Spectroscopy, J. Phys. Chem. A, 1998, 102, 36, 7100, https://doi.org/10.1021/jp9802735 . [all data]

Laufer and Okabe, 1972
Laufer, A.H.; Okabe, H., J. Phys. Chem., 1972, 76, 3504. [all data]

Dixon, de Jong, et al., 2005
Dixon, D.A.; de Jong, W.A.; Peterson, K.A.; McMahon, T.B., Methyl cation affinities of rare gases and nitrogen and the heat of formation of diazomethane, J. Phys. Chem. A, 2005, 109, 18, 4073-4080, https://doi.org/10.1021/jp044561e . [all data]

DePuy, Van Doren, et al., 1989
DePuy, C.H.; Van Doren, J.M.; Gronert, S.; Kass, S.R.; Motell, E.L.; Ellison, G.B.; Bierbaum, V.M., Gas-Phase Negative-Ion Chemistry of Diazomethane, J. Org. Chem., 1989, 54, 8, 1846, https://doi.org/10.1021/jo00269a020 . [all data]

Gordon and Kass, 1997
Gordon, M.S.; Kass, S.R., CHN2-: A biradical anion and a potentially new type of reactive intermediate (vol 99, pg 6548, 1995), J. Phys. Chem. A, 1997, 101, 42, 7922-7922, https://doi.org/10.1021/jp972321b . [all data]

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]

Bastide and Maier, 1976
Bastide, J.; Maier, J.P., Electronic states of the radical cations of the 1,3-dipoles: HCNO, CH₂N₂, and N₃H, studied by photoelectron spectroscopy, Chem. Phys., 1976, 12, 177. [all data]

Merer, 1964
Merer, A.J., The vacuum ultraviolet absorption spectrum of diazomethane, Can. J. Phys., 1964, 42, 1242. [all data]

Paulett and Ettinger, 1963, 2
Paulett, G.S.; Ettinger, R., Mass spectra and appearance potentials of diazirine and diazomethane, J. Chem. Phys., 1963, 39, 825. [all data]

Berkowitz and Wexler, 1962
Berkowitz, J.; Wexler, S., On the ionization potential of the CH₂ radical, J. Chem. Phys., 1962, 37, 1476. [all data]

Notes

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Symbols used in this document:

AE	Appearance energy
IE (evaluated)	Recommended ionization energy
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
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
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