Hydroxymethyl radical

Formula: CH₃O
Molecular weight: 31.0339
IUPAC Standard InChI: InChI=1S/CH3O/c1-2/h2H,1H2
IUPAC Standard InChIKey: CBOIHMRHGLHBPB-UHFFFAOYSA-N
CAS Registry Number: 2597-43-5
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:
- Methyl radical, hydroxy-d1-
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Information on this page:
Other data available:
- Gas phase thermochemistry data
Data at other public NIST sites:
- Gas Phase Kinetics Database
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Gas phase ion energetics data

Go To: Top, Vibrational and/or electronic energy levels, References, Notes

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

Data compiled as indicated in comments:
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 CH₃O⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	166.	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	158.3	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_{(+) ion}	171.6 ± 0.4	kcal/mol	N/A	N/A

Ionization energy determinations

IE (eV)	Method	Reference	Comment
7.562 ± 0.004	EVAL	Johnson and Hudgens, 1996	LL
7.553 ± 0.006	PI	Berkowitz, Ellison, et al., 1994	Unpublished results of B. Ruscic and J. Berkowitz; LL
7.56 ± 0.02	PI	Tao, Klemm, et al., 1992	LL
7.56 ± 0.01	PE	Dyke, Ellis, et al., 1984	LBLHLM
7.6	DER	Griller and Lossing, 1981	LLK
8.14 ± 0.15	EI	Fisher and Henderson, 1967	RDSH
8.14 ± 0.01	PE	Dyke, Ellis, et al., 1984	Vertical value; LBLHLM

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
CHO⁺	8.61	H₂	PI	Tao, Klemm, et al., 1992	LL

Vibrational and/or electronic energy levels

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

Data compiled by: Marilyn E. Jacox

State: 3pz

Energy (cm^-1)	Med.	Transition	λ_min (nm)	λ_max (nm)	References


T_o = 41062 ± 3	gas	3pz-X	217	244	Dulcey and Hudgens, 1986
					Bomse, Dougal, et al., 1986
					Pagsberg, Munk, et al., 1988
					Johnson and Hudgens, 1996
					Aristov, Conroy, et al., 2000

Vib. sym.	No.	Approximate type of mode	cm^-1	Med.	Method	References


a'	4	CO stretch	1621 ± 7	gas	MPI	Dulcey and Hudgens, 1986 Bomse, Dougal, et al., 1986 Johnson and Hudgens, 1996
	5	CH₂ scissors	1465 ± 7	gas	MPI	Dulcey and Hudgens, 1986 Johnson and Hudgens, 1996
	6	HCOH deform.	1357 ± 7	gas	MPI	Dulcey and Hudgens, 1986 Johnson and Hudgens, 1996
	7	HCOH deform.	1107 ± 7	gas	MPI	Dulcey and Hudgens, 1986 Johnson and Hudgens, 1996
a	9	Torsion	993 ± 8	gas	MPI	Johnson and Hudgens, 1996

State: ?

Energy (cm^-1)		Med.	References


T_d = 35700	T	gas	Jacox and Milligan, 1973
			Jacox, 1981

State: 3px

Energy (cm^-1)	Med.	Transition	λ_min (nm)	λ_max (nm)	References


T_o = 35050	gas	3px-X	243	285	Pagsberg, Munk, et al., 1988
					Feng, Huang, et al., 2002

State: 3s

Energy (cm^-1)	Med.	References


T_o = 25980 ± 80	gas	Feng, Huang, et al., 2002

State: X

Vib. sym.	No.	Approximate type of mode	cm^-1		Med.	Method	References


a'	1	OH stretch	3674.9		gas	MPI	Feng, Wei, et al., 2004
	1	OH stretch	3650	m	Ar	IR	Jacox and Milligan, 1973 Jacox, 1981
	1	OH stretch	3637	m	N₂	IR	Jacox and Milligan, 1973
	2	CH₂ a-stretch	3161.5		gas	MPI	Feng, Wei, et al., 2004
	3	CH₂ s-stretch	3043.4		gas	MPI	Feng, Wei, et al., 2004
	4	CH₂ scissors	1459	w	Ar	IR	Jacox, 1981
	5	OH deform.	1334	m	Ar	IR	Jacox and Milligan, 1973 Jacox, 1981
	6	CO stretch	1176 ± 7		gas	MPI	Johnson and Hudgens, 1996
	6	CO stretch	1183	vs	Ar	IR	Jacox and Milligan, 1973 Jacox, 1981
	6	CO stretch	1183	s	N₂	IR	Jacox and Milligan, 1973
	7	HCOH deform.	1048	s	Ar	IR	Jacox and Milligan, 1973 Jacox, 1981
	7	HCOH deform.	1056	m	N₂	IR	Jacox and Milligan, 1973
a	8	Torsion	420	m	Ar	IR	Jacox and Milligan, 1973 Jacox, 1981
	8	Torsion	482	m	N₂	IR	Jacox and Milligan, 1973
	9	H₂CO OPLA	234 ± 5		gas	MPI	Johnson and Hudgens, 1996

Additional references: Jacox, 1994, page 237; Jacox, 1998, page 272; Jacox, 2003, page 258; Pagsberg, Munk, et al., 1989

Notes

Weak

Medium

Strong

Very strong

Tentative assignment or approximate value

Energy separation between the v = 0 levels of the excited and electronic ground states.

Photodissociation threshold

References

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, 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]

Johnson and Hudgens, 1996
Johnson, R.D., III; Hudgens, J.W., Structural and thermochemical properties of hydroxymethyl (CH₂OH) radicals and cations derived from observations of B ²A'(3p)←X ²A" electronic spectra and from ab initio calculations, J. Phys. Chem., 1996, 100, 19874. [all data]

Berkowitz, Ellison, et al., 1994
Berkowitz, J.; Ellison, G.B.; Gutman, D., Three methods to measure RH bond energies, J. Phys. Chem., 1994, 98, 2744. [all data]

Tao, Klemm, et al., 1992
Tao, W.; Klemm, R.B.; Nesbitt, F.L.; Stief, J.L., A discharge flow-photoionization mass spectrometric study of hydroxymethyl radicals (H₂COH and H₂COD): Photoionization spectrum and ionization energy, J. Phys. Chem., 1992, 96, 104. [all data]

Dyke, Ellis, et al., 1984
Dyke, J.M.; Ellis, A.R.; Jonathan, N.; Keddar, N.; Morris, A., Observation of the CH₂OH radical in the gas Ppase by vacuum ultraviolet photoelectron spectroscopy, Chem. Phys. Lett., 1984, 111, 207. [all data]

Griller and Lossing, 1981
Griller, D.; Lossing, F.P., On the thermochemistry of α-aminoalkyl radicals, J. Am. Chem. Soc., 1981, 103, 1586. [all data]

Fisher and Henderson, 1967
Fisher, I.P.; Henderson, E., Mass spectrometry of free radicals, J. Chem. Soc. Faraday Trans., 1967, 63, 1342. [all data]

Dulcey and Hudgens, 1986
Dulcey, C.S.; Hudgens, J.W., Multiphoton ionization spectroscopy and vibrational analysis of a 3p Rydberg state of the hydroxymethyl radical, J. Chem. Phys., 1986, 84, 10, 5262, https://doi.org/10.1063/1.449935 . [all data]

Bomse, Dougal, et al., 1986
Bomse, D.S.; Dougal, S.; Woodin, R.L., Multiphoton ionization studies of IR multiphoton dissociation: direct carbon-hydrogen bond cleavage in methanol, J. Phys. Chem., 1986, 90, 12, 2640, https://doi.org/10.1021/j100403a016 . [all data]

Pagsberg, Munk, et al., 1988
Pagsberg, P.; Munk, J.; Sillesen, A.; Anastasi, C., UV spectrum and kinetics of hydroxymethyl radicals, Chem. Phys. Lett., 1988, 146, 5, 375, https://doi.org/10.1016/0009-2614(88)87462-1 . [all data]

Aristov, Conroy, et al., 2000
Aristov, V.; Conroy, D.; Reisler, H., Symmetry and lifetime of the hydroxymethyl radical in the 3p Rydberg state, Chem. Phys. Lett., 2000, 318, 4-5, 393, https://doi.org/10.1016/S0009-2614(00)00042-7 . [all data]

Jacox and Milligan, 1973
Jacox, M.E.; Milligan, D.E., Matrix isolation study of the vacuum-ultraviolet photolysis of methanol, J. Mol. Spectrosc., 1973, 47, 1, 148, https://doi.org/10.1016/0022-2852(73)90084-2 . [all data]

Jacox, 1981
Jacox, M.E., The reaction of excited argon atoms and of F atoms with Methanol. Vibrational spectrum of CH2OH isolated in solid argon, Chem. Phys., 1981, 59, 1-2, 213, https://doi.org/10.1016/0301-0104(81)80101-2 . [all data]

Feng, Huang, et al., 2002
Feng, L.; Huang, X.; Reisler, H., Photodissociative spectroscopy of the hydroxymethyl radical (CH[sub 2]OH) in the 3s and 3p[sub x] states, J. Chem. Phys., 2002, 117, 10, 4820, https://doi.org/10.1063/1.1498469 . [all data]

Feng, Wei, et al., 2004
Feng, L.; Wei, J.; Reisler, H., Rotationally Resolved Infrared Spectroscopy of the Hydroxymethyl Radical (CH, J. Phys. Chem. A, 2004, 108, 39, 7903, https://doi.org/10.1021/jp040101+ . [all data]

Jacox, 1994
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]

Jacox, 1998
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement A, J. Phys. Chem. Ref. Data, 1998, 27, 2, 115-393, https://doi.org/10.1063/1.556017 . [all data]

Jacox, 2003
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement B, J. Phys. Chem. Ref. Data, 2003, 32, 1, 1-441, https://doi.org/10.1063/1.1497629 . [all data]

Pagsberg, Munk, et al., 1989
Pagsberg, P.; Munk, J.; Anastasi, C.; Simpson, V., UV spectrum of CD2OD and its reactions with O2, NO and NO2, Chem. Phys. Lett., 1989, 157, 3, 271, https://doi.org/10.1016/0009-2614(89)87246-X . [all data]

Notes

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, References

Symbols used in this document:

AE Appearance energy
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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