Dicarbon monoxide

Formula: C₂O
Molecular weight: 40.0208
IUPAC Standard InChI: InChI=1S/C2O/c1-2-3
IUPAC Standard InChIKey: VILAVOFMIJHSJA-UHFFFAOYSA-N
CAS Registry Number: 119754-08-4
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Species with the same structure:
- Dicarbon monoxide
Information on this page:
Other data available:
- Gas phase ion energetics data
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Gas phase thermochemistry data

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

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	286.60	kJ/mol	Review	Chase, 1998	Data last reviewed in September, 1966
Quantity	Value	Units	Method	Reference	Comment
S°_{gas,1 bar}	233.07	J/mol*K	Review	Chase, 1998	Data last reviewed in September, 1966

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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Temperature (K)	298. to 1300.	1300. to 6000.
A	34.22445	60.64080
B	41.04408	4.317511
C	-23.52973	-1.109681
D	5.537273	0.082437
E	-0.129471	-8.056669
F	274.3386	252.4044
G	262.5142	286.0283
H	286.6044	286.6044
Reference	Chase, 1998	Chase, 1998
Comment	Data last reviewed in September, 1966	Data last reviewed in September, 1966

Vibrational and/or electronic energy levels

Go To: Top, Gas phase thermochemistry data, References, Notes

Data compiled by: Marilyn E. Jacox

State: c

Energy (cm^-1)	Med.	References


T_o = 22390 ± 160	gas	Choi, Mordaunt, et al., 1998

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


Σ⁺	3	CC stretch	1234 ± 140	gas	PE	Choi, Mordaunt, et al., 1998

State: ?

Energy (cm^-1)		Med.	References


T_d = 20000	T	Ar	Jacox, Milligan, et al., 1965

State: A

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


T_o = 11651.182	gas	A-X	500	860	Devillers, 1966
					Devillers and Ramsay, 1971
					Pitts, Donnelly, et al., 1981
					Fujitake, Kiryu, et al., 1992
					Ohashi, Kiryu, et al., 1993
					Abe, Kikuchi, et al., 1994
					Abe, Kawamoto, et al., 1996
					Abe, Mukai, et al., 1999
					Garand, Yacovitch, et al., 2008
T_o = 11650 ± 3	Ne				Fulara, Grutter, et al., 1998
T_o = 11860	Ar	A-X	600	850	Smith and Weltner, 1975

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


Σ⁺	1	CO stretch	2045.7	gas	AB	Devillers and Ramsay, 1971
	1	CO stretch	2045 ± 3	Ne	AB	Fulara, Grutter, et al., 1998
Π	2	Bend	594.75	gas	AB DL	Devillers and Ramsay, 1971 Abe, Kikuchi, et al., 1994 Ohashi and Fujitake, 2004
Σ⁺	3	CC stretch	1283.60	gas	DL PE	Devillers and Ramsay, 1971 Abe, Kawamoto, et al., 1996 Garand, Yacovitch, et al., 2008
	3	CC stretch	1279 ± 3	Ne	AB	Fulara, Grutter, et al., 1998

State: b

Energy (cm^-1)	Med.	References


T_o = 8205 ± 5	gas	Zengin, Persson, et al., 1996
		Choi, Mordaunt, et al., 1998
		Garand, Yacovitch, et al., 2008

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


Σ⁺	1	CO stretch	1900 ± 7	gas	PE	Zengin, Persson, et al., 1996 Choi, Mordaunt, et al., 1998 Garand, Yacovitch, et al., 2008

State: a

Energy (cm^-1)	Med.	References


T_o = 5276 ± 5	gas	Zengin, Persson, et al., 1996
		Choi, Mordaunt, et al., 1998
		Garand, Yacovitch, et al., 2008

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


Σ⁺	1	CO stretch	1942.85	gas	PE DL	Zengin, Persson, et al., 1996 Choi, Mordaunt, et al., 1998 Moazzen-Ahmadi and Boere, 1999 Garand, Yacovitch, et al., 2008
	3	CC stretch	1082.03	gas	DL	Abusara, Sorensen, et al., 2004

State: X

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


Σ⁺	1	CO stretch	1970.86		gas	LF DL	Pitts, Donnelly, et al., 1981 Yamada, Kanamori, et al., 1986 Moazzen-Ahmadi, Sandilands, et al., 1997 Garand, Yacovitch, et al., 2008
	1	CO stretch	1969	s	Ar	IR	Jacox, Milligan, et al., 1965 DeKock and Weltner, 1971
	1	CO stretch	1978		Ar	IR	Jacox, Milligan, et al., 1965
	1	CO stretch	1987		N₂	IR	Jacox, Milligan, et al., 1965
Π	2	Bend	379.53		gas	AB	Devillers and Ramsay, 1971 Ohashi, Kiryu, et al., 1993
Π_u	2	Bend	381	m	Ar	IR	Jacox, Milligan, et al., 1965
Σ⁺	3	CC stretch	1066.82		gas	LF DL	Pitts, Donnelly, et al., 1981 Abusara, Sorensen, et al., 2003
	3	CC stretch	1064	w	Ar	IR	Jacox, Milligan, et al., 1965
	3	CC stretch	1074		Ar	IR	Jacox, Milligan, et al., 1965
	3	CC stretch	1077		N₂	IR	Jacox, Milligan, et al., 1965

Additional references: Jacox, 1994, page 69; Jacox, 1998, page 179; Jacox, 2003, page 111; Pitts, Donnelly, et al., 1981, 2; Yamada, Saito, et al., 1985; Ohshima, Endo, et al., 1995

Notes

Weak

Medium

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 thermochemistry data, Vibrational and/or electronic energy levels, Notes

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Choi, Mordaunt, et al., 1998
Choi, H.; Mordaunt, D.H.; Bise, R.T.; Taylor, T.R.; Neumark, D.M., Photodissociation of triplet and singlet states of the CCO radical, J. Chem. Phys., 1998, 108, 10, 4070, https://doi.org/10.1063/1.475839 . [all data]

Jacox, Milligan, et al., 1965
Jacox, M.E.; Milligan, D.E.; Moll, N.G.; Thompson, W.E., Matrix-Isolation Infrared Spectrum of the Free Radical CCO, J. Chem. Phys., 1965, 43, 10, 3734, https://doi.org/10.1063/1.1696543 . [all data]

Devillers, 1966
Devillers, C., Compt. Rend. Acad. Sci. (Paris), 1966, 262C, 1485. [all data]

Devillers and Ramsay, 1971
Devillers, C.; Ramsay, D.A., The Band System of the CCO Molecule, Can. J. Phys., 1971, 49, 22, 2839, https://doi.org/10.1139/p71-342 . [all data]

Pitts, Donnelly, et al., 1981
Pitts, W.M.; Donnelly, V.M.; Baronavski, A.P.; McDonald, J.R., C2O(Ã 3Πi↔-~X3Σ-: laser induced excitation and fluorescence spectra, Chem. Phys., 1981, 61, 3, 451, https://doi.org/10.1016/0301-0104(81)85161-0 . [all data]

Fujitake, Kiryu, et al., 1992
Fujitake, M.; Kiryu, R.; Ohashi, N., Near-infrared diode laser spectroscopy of the CCO radical in the band, J. Mol. Spectrosc., 1992, 154, 1, 169, https://doi.org/10.1016/0022-2852(92)90037-O . [all data]

Ohashi, Kiryu, et al., 1993
Ohashi, N.; Kiryu, R.; Okino, S.; Fujitake, M., Near-Infrared Diode Laser Spectroscopy of the CCO Radical: Molecular Constants for the X3Σ-(010) State, J. Mol. Spectrosc., 1993, 157, 1, 50, https://doi.org/10.1006/jmsp.1993.1004 . [all data]

Abe, Kikuchi, et al., 1994
Abe, H.; Kikuchi, T.; Takahashi, K.; Fujitake, M.; Ohashi, N., Near-Infrared Diode Laser Spectroscopy of the CCO Radical: Analysis of the Ã(010)3Σ(+) and Ã(010)3Σ(-) States, J. Mol. Spectrosc., 1994, 167, 2, 353, https://doi.org/10.1006/jmsp.1994.1241 . [all data]

Abe, Kawamoto, et al., 1996
Abe, H.; Kawamoto, Y.; Fujitake, M.; Ohashi, N.; Momose, T.; Shida, T., Laser Spectroscopy of the CCO Radical in the 0.77-μm Region: Analysis of theÃ(020)κ3Π andÃ3Πi(001) States, J. Mol. Spectrosc., 1996, 180, 2, 277, https://doi.org/10.1006/jmsp.1996.0250 . [all data]

Abe, Mukai, et al., 1999
Abe, H.; Mukai, M.; Fujitaki, M.; Ohashi, N., Near-Infrared Diode--Laser Spectroscopy of the CCO Radical in theÃ(010)3Δ--X(010)3Π(b) Band, J. Mol. Spectrosc., 1999, 195, 2, 317, https://doi.org/10.1006/jmsp.1999.7835 . [all data]

Garand, Yacovitch, et al., 2008
Garand, E.; Yacovitch, T.I.; Neumark, D.M., Slow photoelectron imaging spectroscopy of CCO- and CCS-, J. Chem. Phys., 2008, 129, 7, 074312, https://doi.org/10.1063/1.2969819 . [all data]

Fulara, Grutter, et al., 1998
Fulara, J.; Grutter, M.; Wyss, M.; Maier, J.P., A, J. Phys. Chem. A, 1998, 102, 20, 3459, https://doi.org/10.1021/jp980879t . [all data]

Smith and Weltner, 1975
Smith, G.R.; Weltner, W., Jr., ESR of the triplet molecules CCO and CNN in rare-gas matrices; isotope and matrix effects, J. Chem. Phys., 1975, 62, 12, 4592, https://doi.org/10.1063/1.430432 . [all data]

Ohashi and Fujitake, 2004
Ohashi, N.; Fujitake, M., Spectrochim. Acta, 2004, 60A, 3277. [all data]

Zengin, Persson, et al., 1996
Zengin, V.; Persson, B.J.; Strong, K.M.; Continetti, R.E., Study of the Low-lying Electronic States of CCO by Photoelectron Spectroscopy of CCO- and ab initio calculations., J. Chem. Phys., 1996, 105, 22, 9740, https://doi.org/10.1063/1.473000 . [all data]

Moazzen-Ahmadi and Boere, 1999
Moazzen-Ahmadi, N.; Boere, R.T., Infrared laser spectroscopy of CCO: The ν[sub 1] band of the a[sup 1]Δ electronic state, J. Chem. Phys., 1999, 110, 2, 955, https://doi.org/10.1063/1.478140 . [all data]

Abusara, Sorensen, et al., 2004
Abusara, Z.; Sorensen, T.S.; Moazzen-Ahmadi, N., Infrared laser spectroscopy of CCO: the ν3 band of the electronic state and 3ν3--2ν3 band of the ground electronic state, Chem. Phys. Lett., 2004, 388, 1-3, 62, https://doi.org/10.1016/j.cplett.2004.03.010 . [all data]

Yamada, Kanamori, et al., 1986
Yamada, C.; Kanamori, H.; Horiguchi, H.; Tsuchiya, S.; Hirota, E., Infrared diode laser kinetic spectroscopy of the CCO radical in the X 3Σ- state generated by the excimer laser photolysis of carbon suboxide, J. Chem. Phys., 1986, 84, 5, 2573, https://doi.org/10.1063/1.450835 . [all data]

Moazzen-Ahmadi, Sandilands, et al., 1997
Moazzen-Ahmadi, N.; Sandilands, D.W.D.; Boere, R.T., Infrared diode laser spectroscopy of the ν1 fundamental and the ν1 + ν2 - ν2 sequence bands of the CCO radical, Chem. Phys. Lett., 1997, 265, 6, 563, https://doi.org/10.1016/S0009-2614(96)01451-0 . [all data]

DeKock and Weltner, 1971
DeKock, R.L.; Weltner, W., Jr., C2O, CN2, and C3O molecules, J. Am. Chem. Soc., 1971, 93, 25, 7106, https://doi.org/10.1021/ja00754a081 . [all data]

Abusara, Sorensen, et al., 2003
Abusara, Z.; Sorensen, T.S.; Moazzen-Ahmadi, N., Infrared laser spectroscopy of CCO radical in the region of the C--C stretching fundamental, J. Chem. Phys., 2003, 119, 18, 9491, https://doi.org/10.1063/1.1615752 . [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]

Pitts, Donnelly, et al., 1981, 2
Pitts, W.M.; Donnelly, V.M.; Baronavski, A.P.; McDonald, J.R., Excited state dynamics of C2O( 3Πi), Chem. Phys., 1981, 61, 3, 465, https://doi.org/10.1016/0301-0104(81)85162-2 . [all data]

Yamada, Saito, et al., 1985
Yamada, C.; Saito, S.; Kanamori, H.; Hirota, E., Millimeter-wave spectrum of the CCO radical, Astrophys. J., 1985, 290, L65, https://doi.org/10.1086/184444 . [all data]

Ohshima, Endo, et al., 1995
Ohshima, Y.; Endo, Y.; Ogata, T., Fourier-transform microwave spectroscopy of triplet carbon monoxides, C2O, C4O, C6O, and C8O, J. Chem. Phys., 1995, 102, 4, 1493, https://doi.org/10.1063/1.468881 . [all data]

Notes

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

Symbols used in this document:

S°_{gas,1 bar} Entropy of gas at standard conditions (1 bar)

Δ_fH°_gas Enthalpy of formation of gas at standard conditions
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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S°_{gas,1 bar}	Entropy of gas at standard conditions (1 bar)
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions