Hydrocarboxyl radical

Formula: CHO₂
Molecular weight: 45.0174
IUPAC Standard InChI: InChI=1S/CHO2/c2-1-3/h(H,2,3)
IUPAC Standard InChIKey: ORTFAQDWJHRMNX-UHFFFAOYSA-N
CAS Registry Number: 2564-86-5
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:
- Hydroxycarbonyl-d1
Permanent link for this species. Use this link for bookmarking this species for future reference.
Information on this page:
Options:
- Switch to SI units

Gas phase ion energetics data

Go To: Top, Vibrational and/or electronic energy levels, NIST Free Links, 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
B - John E. Bartmess

View reactions leading to CHO₂⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	149.0	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	141.2	kcal/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_{(+) ion}	143. ± 2.	kcal/mol	N/A	N/A
Quantity	Value	Units	Method	Reference	Comment
Δ_fH_{(+) ion,0K}	141. ± 2.	kcal/mol	N/A	N/A

Electron affinity determinations

EA (eV)	Method	Reference	Comment
1.510 ± 0.010	LPES	Johnson, Harding, et al., 2011	trans isomer. See Wang, Li, et al., 2014 for computational analysis; B
1.380 ± 0.010	LPES	Johnson, Harding, et al., 2011	cis isomer; B
3.4961 ± 0.0010	LPES	Garand, Klein, et al., 2010	B
1.18	LPES	Lu, Hu, et al., 2007	Stated EA is Vertical Detachment Energy. See also Johnson and Continetti, 2010 for cooled ions (same EA); B
2.180 ± 0.020	LPES	Clements, Continetti, et al., 2002	B
3.498 ± 0.015	LPES	Kim, Bradforth, et al., 1995	dHacid(0K) = 344.67±0.62 kcal/mol; B
3.54 ± 0.11	D-EA	Caldwell, Renneboog, et al., 1989	B

Ionization energy determinations

IE (eV)	Method	Reference	Comment
8.20	DER	Berkowitz, Ellison, et al., 1994	LL
8.486 ± 0.012	PI	Ruscic, Schwartz, et al., 1989	LL

Vibrational and/or electronic energy levels

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

Data compiled by: Marilyn E. Jacox

State: X

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


a'	1	OH stretch	3635.70		gas	LD	Petty and Moore, 1993
	1	OH stretch	3628.0	w m	Ne	IR	Forney, Jacox, et al., 2003
	1	OH stretch	3602.9		Ar	IR	Jacox, 1988
	1	OH stretch	3570.8		N₂	IR	Mielke, Olbert-Majkut, et al., 2003
	1	OH stretch	3456		CO	IR	Milligan and Jacox, 1971
	2	C=O stretch	1852.57		gas	DL	Sears, Fawzy, et al., 1992
	2	C=O stretch	1848.0	s	Ne	IR	Forney, Jacox, et al., 2003
	2	C=O stretch	1843.6		Ar	IR	Jacox, 1988
	2	C=O stretch	1837.8		N₂	IR	Mielke, Olbert-Majkut, et al., 2003
	2	C=O stretch	1833		CO	IR	Milligan and Jacox, 1971
	3	HOC bend	1194 ± 10		gas	PE	Johnson, Poad, et al., 2011
	3	HOC bend	1210.4	m	Ne	IR	Forney, Jacox, et al., 2003
	3	HOC bend	1211.2		Ar	IR	Jacox, 1988
	3	HOC bend	1241.1		N₂	IR	Mielke, Olbert-Majkut, et al., 2003
	3	HOC bend	1261		CO	IR	Milligan and Jacox, 1971
	4	C-O stretch	1048 ± 10		gas	PE	Johnson, Poad, et al., 2011
	4	C-O stretch	1050.4	w m	Ne	IR	Forney, Jacox, et al., 2003
	4	C-O stretch	1064.6		Ar	IR	Jacox, 1988
	4	C-O stretch	1062.8		N₂	IR	Mielke, Olbert-Majkut, et al., 2003
	4	C-O stretch	1077		CO	IR	Milligan and Jacox, 1971
	5	OCO bend	629 ± 5		gas	PE	Johnson, Poad, et al., 2011
	5	OCO bend	615		CO	IR	Milligan and Jacox, 1971
a	6	Torsion	508.1	w m	Ne	IR	Forney, Jacox, et al., 2003
	6	Torsion	515		Ar	IR	Jacox, 1988

Additional references: Jacox, 1994, page 167; Jacox, 1998, page 236; Radford, Wei, et al., 1992; Sears, Radford, et al., 1993; Petty and Moore, 1993, 2; Radford, Moore, et al., 1994; Oyama, Funato, et al., 2011

Notes

Weak

Medium

Strong

References

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, NIST Free Links, 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, Harding, et al., 2011
Johnson, C.J.; Harding, M.E.; Poad, B.L.J.; Stanton, J.F.; Continetti, R.E., Electron Affinities, Well Depths, and Vibrational Spectroscopy of cis- and trans-HOCO, J. Am. Chem. Soc., 2011, 133, 49, 19606-19609, https://doi.org/10.1021/ja207724f . [all data]

Wang, Li, et al., 2014
Wang, J.; Li, J.; Ma, J.Y.; Guo, H., Full-dimensional characterization of photoelectron spectra of HOCO- and DOCO- and tunneling facilitated decay of HOCO prepared by anion photodetachment, Journal Of Chemical Physics, 2014, 140, 18, 184314, https://doi.org/10.1063/1.4874975 . [all data]

Garand, Klein, et al., 2010
Garand, E.; Klein, K.; Stanton, J.F.; Zhou, J.; Yacovitch, T.I.; Neumark, D.M., Vibronic Structure of the Formyloxyl Radical (HCO2) via Slow Photoelectron Velocity-Map Imaging Spectroscopy and Model Hamiltonian Calculations, J. Phys. Chem. A, 2010, 114, 3, 1374-1383, https://doi.org/10.1021/jp9067894 . [all data]

Lu, Hu, et al., 2007
Lu, Z.; Hu, Q.C.; Oakman, J.E.; Continetti, R.E., Dynamics on the HOCO potential energy surface studied by dissociative photodetachment of HOCO- and DOCO-, J. Chem. Phys., 2007, 126, 19, 194305, https://doi.org/10.1063/1.2731787 . [all data]

Johnson and Continetti, 2010
Johnson, C.J.; Continetti, R.E., Dissociative Photodetachment Studies of Cooled HOCO- Anions Revealing Dissociation Below the Barrier to H + CO2, J. Phys. Chem. Lett., 2010, 1, 12, 1895-1899, https://doi.org/10.1021/jz100621k . [all data]

Clements, Continetti, et al., 2002
Clements, T.G.; Continetti, R.E.; Francisco, J.S., Exploring the OH+CO - H+CO2 potential surface via dissociative photodetachment of (HOCO)(-), J. Chem. Phys., 2002, 117, 14, 6478-6488, https://doi.org/10.1063/1.1505439 . [all data]

Kim, Bradforth, et al., 1995
Kim, E.H.; Bradforth, S.E.; Arnold, D.W.; Metz, R.B.; Neumark, D.M., Study of HCO2 and DCO2 by Negative Ion Photoelectron Spectroscopy, J. Chem. Phys., 1995, 103, 18, 7801, https://doi.org/10.1063/1.470196 . [all data]

Caldwell, Renneboog, et al., 1989
Caldwell, G.; Renneboog, R.; Kebarle, P., Gas Phase Acidities of Aliphatic Carboxylic Acids, Based on Measurements of Proton Transfer Equilibria, Can. J. Chem., 1989, 67, 4, 661, https://doi.org/10.1139/v89-092 . [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]

Ruscic, Schwartz, et al., 1989
Ruscic, B.; Schwartz, M.; Berkowitz, J., A photoionization study of the COOH species, J. Chem. Phys., 1989, 91, 6780. [all data]

Petty and Moore, 1993
Petty, J.T.; Moore, C.B., Transient Infrared Absorption Spectrum of the ν1 Fundamental of trans-HOCO, J. Mol. Spectrosc., 1993, 161, 1, 149, https://doi.org/10.1006/jmsp.1993.1223 . [all data]

Forney, Jacox, et al., 2003
Forney, D.; Jacox, M.E.; Thompson, W.E., Infrared spectra of trans-HOCO, HCOOH[sup +], and HCO[sub 2][sup -] trapped in solid neon, J. Chem. Phys., 2003, 119, 20, 10814, https://doi.org/10.1063/1.1621382 . [all data]

Jacox, 1988
Jacox, M.E., The vibrational spectrum of the t-HOCO free radical trapped in solid argon, J. Chem. Phys., 1988, 88, 8, 4598, https://doi.org/10.1063/1.453772 . [all data]

Mielke, Olbert-Majkut, et al., 2003
Mielke, Z.; Olbert-Majkut, A.; Tokhadze, K.G., Photolysis of the OC...HONO complex in low temperature matrices: Infrared detection and ab initio calculations of nitrosoformic acid, HOC(O)NO, J. Chem. Phys., 2003, 118, 3, 1364, https://doi.org/10.1063/1.1528897 . [all data]

Milligan and Jacox, 1971
Milligan, D.E.; Jacox, M.E., Infrared Spectrum and Structure of Intermediates in the Reaction of OH with CO, J. Chem. Phys., 1971, 54, 3, 927, https://doi.org/10.1063/1.1675022 . [all data]

Sears, Fawzy, et al., 1992
Sears, T.J.; Fawzy, W.M.; Johnson, P.M., Transient diode laser absorption spectroscopy of the ν2 fundamental of trans-HOCO and DOCO, J. Chem. Phys., 1992, 97, 6, 3996, https://doi.org/10.1063/1.462939 . [all data]

Johnson, Poad, et al., 2011
Johnson, C.J.; Poad, M.E. Harding.B.L.J.; Stanton, J.F.; Continetti, R.E., Electron Affinities, Well Depths, and Vibrational Spectroscopy of, J. Am. Chem. Soc., 2011, 133, 49, 19606, https://doi.org/10.1021/ja207724f . [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]

Radford, Wei, et al., 1992
Radford, H.E.; Wei, W.; Sears, T.J., The rotational spectrum of trans-HOCO and DOCO, J. Chem. Phys., 1992, 97, 6, 3989, https://doi.org/10.1063/1.462938 . [all data]

Sears, Radford, et al., 1993
Sears, T.J.; Radford, H.E.; Moore, M.A., b-dipole transitions in trans-HOCO observed by far infrared laser magnetic resonance, J. Chem. Phys., 1993, 98, 9, 6624, https://doi.org/10.1063/1.465098 . [all data]

Petty and Moore, 1993, 2
Petty, J.T.; Moore, C.B., Transient infrared absorption spectrum of the ν1 fundamental of trans-DOCO, J. Chem. Phys., 1993, 99, 1, 47, https://doi.org/10.1063/1.465773 . [all data]

Radford, Moore, et al., 1994
Radford, H.E.; Moore, M.A.; Sears, T.J.; Grussdorf, J.; Nolte, J.; Temps, F., Far-Infrared Laser Magnetic Resonance of X2A´ trans-DOCO, J. Mol. Spectrosc., 1994, 165, 1, 137, https://doi.org/10.1006/jmsp.1994.1116 . [all data]

Oyama, Funato, et al., 2011
Oyama, T.; Funato, W.; Sumiyoshi, Y.; Endo, Y., Observation of the pure rotational spectra of trans- and cis-HOCO, J. Chem. Phys., 2011, 134, 17, 174303, https://doi.org/10.1063/1.3578179 . [all data]

Notes

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

Symbols used in this document:

EA Electron affinity

Δ_fH_{(+) ion,0K} Enthalpy of formation of positive ion at 0K
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.

EA	Electron affinity
Δ_fH_{(+) ion,0K}	Enthalpy of formation of positive ion at 0K