Ethynyloxy radical

Formula: C₂HO
Molecular weight: 41.0287
IUPAC Standard InChI: InChI=1S/C2HO/c1-2-3/h1H
IUPAC Standard InChIKey: QEJQAPYSVNHDJF-UHFFFAOYSA-N
CAS Registry Number: 51095-15-9
Chemical structure:
This structure is also available as a 2d Mol file
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Gas phase ion energetics data

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

Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
B - John E. Bartmess

View reactions leading to C₂HO⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_{(+) ion}	1120.	kJ/mol	N/A	N/A

Electron affinity determinations

EA (eV)	Method	Reference	Comment
2.3380 ± 0.0080	LPES	Schafer-Bung, Engels, et al., 2001	B
2.350 ± 0.022	LPES	Oakes, Jones, et al., 1983	value altered from reference due to change in acidity scale; B

Ionization energy determinations

IE (eV)	Method	Reference	Comment
9.5	DER	Lias, Bartmess, et al., 1988	LL

Vibrational and/or electronic energy levels

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

Data compiled by: Marilyn E. Jacox

State: B

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


T_o = 33464.75 ± 0.05	gas	B-X	263	300	Mordaunt, Osborn, et al., 1996
					Osborn, Mordaunt, et al., 1997
					Brock, Mischler, et al., 1997
					Brock, Mischler, et al., 1999

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


Σ⁺	3	CCO s-stretch	1037	gas	PF LF	Osborn, Mordaunt, et al., 1997 Brock, Mischler, et al., 1997 Brock, Mischler, et al., 1999
Π	4	HCC deform.(2S)	750.7	gas	LF	Brock, Mischler, et al., 1999
	4	HCC deform.(2S)	564.3	gas	LF	Brock, Mischler, et al., 1999
	5	CCO deform.(2S)	382.0	gas	LF	Brock, Mischler, et al., 1999
	5	CCO deform.(2S)	346.6	gas	LF	Brock, Mischler, et al., 1999

State: X

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


a'	1	CH stretch	3232	T	gas	EM	Wilhelm, McNavage, et al., 2008
	2	CCO a-stretch	2022.64		gas	DL	Unfried and Curl, 1991
	2	CCO a-stretch	2023.7		Ne	IR	Forney, Jacox, et al., 1995
	2	CCO a-stretch	2019.5		Ar	IR	Jacox and Olson, 1987
a	6	CCH bend	494		gas	LF	Brock, Mischler, et al., 1997

Additional references: Jacox, 1994, page 156; Jacox, 1998, page 234; Jacox, 2003, page 188; Endo and Hirota, 1987; Ohshima and Endo, 1993; Schafer-Bung, Engels, et al., 2001, 2

Notes

Tentative assignment or approximate value

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

References

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

Schafer-Bung, Engels, et al., 2001
Schafer-Bung, B.; Engels, B.; Taylor, T.R.; Neumark, D.M.; Botschwina, P.; Peric, M., Measurement and theoretical simulation of the HCCO- anion photoelectron spectrum, J. Chem. Phys., 2001, 115, 4, 1777-1788, https://doi.org/10.1063/1.1378041 . [all data]

Oakes, Jones, et al., 1983
Oakes, J.M.; Jones, M.E.; Bierbaum, V.M.; Ellison, G.B., Photoelectron spectroscopy of CCO^- and HCCO^-, J. Phys. Chem., 1983, 87, 4810. [all data]

Lias, Bartmess, et al., 1988
Lias, S.G.; Bartmess, J.E.; Liebman, J.F.; Holmes, J.L.; Levin, R.D.; Mallard, W.G., Gas-phase ion and neutral thermochemistry, J. Phys. Chem. Ref. Data, Suppl. 1, 1988, 17, 1-861. [all data]

Mordaunt, Osborn, et al., 1996
Mordaunt, D.H.; Osborn, D.L.; Choi, H.; Bise, R.T.; Neumark, D.M., Ultraviolet photodissociation of the HCCO radical studied by fast radical beam photofragment translational spectroscopy, J. Chem. Phys., 1996, 105, 14, 6078, https://doi.org/10.1063/1.472446 . [all data]

Osborn, Mordaunt, et al., 1997
Osborn, D.L.; Mordaunt, D.H.; Choi, H.; Bise, R.T.; Neumark, D.M.; Rohlfing, C.M., Photodissociation spectroscopy and dynamics of the HCCO free radical, J. Chem. Phys., 1997, 106, 24, 10087, https://doi.org/10.1063/1.474064 . [all data]

Brock, Mischler, et al., 1997
Brock, L.R.; Mischler, B.; Rohlfing, E.A.; Bise, R.T.; Neumark, D.M., Laser-induced fluorescence spectroscopy of the ketenyl radical, J. Chem. Phys., 1997, 107, 2, 665, https://doi.org/10.1063/1.474427 . [all data]

Brock, Mischler, et al., 1999
Brock, L.R.; Mischler, B.; Rohlfing, E.A., Laser-induced fluorescence spectroscopy of the B [sup 2]Π--X [sup 2]A[sup ´´] band system of HCCO and DCCO, J. Chem. Phys., 1999, 110, 14, 6773, https://doi.org/10.1063/1.478581 . [all data]

Wilhelm, McNavage, et al., 2008
Wilhelm, M.J.; McNavage, W.; Groller, R.; Dai, H.-L., The ν[sub 1] CH stretching mode of the ketenyl (HCCO) radical, J. Chem. Phys., 2008, 128, 6, 064313, https://doi.org/10.1063/1.2829400 . [all data]

Unfried and Curl, 1991
Unfried, K.G.; Curl, R.F., Infrared flash kinetic spectroscopy of ν2 of ketenyl radical, J. Mol. Spectrosc., 1991, 150, 1, 86, https://doi.org/10.1016/0022-2852(91)90195-G . [all data]

Forney, Jacox, et al., 1995
Forney, D.; Jacox, M.E.; Thompson, W.E., The Infrared and Near-Infrared Spectra of HCC and DCC Trapped in Solid Neon, J. Mol. Spectrosc., 1995, 170, 1, 178, https://doi.org/10.1006/jmsp.1995.1065 . [all data]

Jacox and Olson, 1987
Jacox, M.E.; Olson, W.B., The A 2Π--X 2Σ+ transition of HC2 isolated in solid argon, J. Chem. Phys., 1987, 86, 6, 3134, https://doi.org/10.1063/1.452024 . [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]

Endo and Hirota, 1987
Endo, Y.; Hirota, E., The submillimeter-wave spectrum of the HCCO radical, J. Chem. Phys., 1987, 86, 8, 4319, https://doi.org/10.1063/1.451892 . [all data]

Ohshima and Endo, 1993
Ohshima, Y.; Endo, Y., Determination of the Hyperfine Constants for HCCO by Pulsed-Discharge-Nozzle Fourier-Transform Microwave Spectroscopy, J. Mol. Spectrosc., 1993, 159, 2, 458, https://doi.org/10.1006/jmsp.1993.1142 . [all data]

Schafer-Bung, Engels, et al., 2001, 2
Schafer-Bung, B.; Engels, B.; Taylor, T.R.; Neumark, D.M.; Botschwina, P.; Peric, M., Measurement and theoretical simulation of the HCCO[sup -] anion photoelectron spectrum, J. Chem. Phys., 2001, 115, 4, 1777, https://doi.org/10.1063/1.1378041 . [all data]

Notes

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

Symbols used in this document:

EA Electron affinity
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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