Furan

Formula: C₄H₄O
Molecular weight: 68.0740
IUPAC Standard InChI: InChI=1S/C4H4O/c1-2-4-5-3-1/h1-4H
IUPAC Standard InChIKey: YLQBMQCUIZJEEH-UHFFFAOYSA-N
CAS Registry Number: 110-00-9
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: Divinylene oxide; Furfuran; Oxacyclopentadiene; Oxole; Tetrole; Furane; Furfurane; NCI-C56202; Rcra waste number U124; UN 2389; 1,4-Epoxy-1,3-butadiene
Permanent link for this species. Use this link for bookmarking this species for future reference.
Information on this page:
Other data available:
Data at other public NIST sites:
- Computational Chemistry Comparison and Benchmark Database
- Gas Phase Kinetics Database
Options:
- Switch to calorie-based units

Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.

Gas phase thermochemistry data

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

Data compiled as indicated in comments:
DRB - Donald R. Burgess, Jr.
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	-27.7	kJ/mol	N/A	Zaheeruddin and Lodhi, 1991	Value computed using Δ_fH_liquid° value of -55.4 kj/mol from Zaheeruddin and Lodhi, 1991 and Δ_vapH° value of 27.6 kj/mol from Guthrie, Scott, et al., 1952.; DRB
Δ_fH°_gas	-34.7	kJ/mol	Ccb	Guthrie, Scott, et al., 1952	ALS
Δ_fH°_gas	-29.8	kJ/mol	N/A	Landrieu, Baylocq, et al., 1929	Value computed using Δ_fH_liquid° value of -57.5 kj/mol from Landrieu, Baylocq, et al., 1929 and Δ_vapH° value of 27.6 kj/mol from Guthrie, Scott, et al., 1952.; DRB

Constant pressure heat capacity of gas

C_p,gas (J/mol*K)	Temperature (K)	Reference	Comment
33.26	50.	Dorofeeva O.V., 1992	p=1 bar. Selected entropies and heat capacities are in good agreement with those obtained in other statistical calculations [ Guthrie G.B., 1952, Bak B., 1955, Rico M., 1967, Soptrajanov B., 1968, Chao J., 1986, Klots T.D., 1994].; GT
33.53	100.
36.39	150.
43.60	200.
59.43	273.15
65.4 ± 1.5	298.15
65.85	300.
88.80	400.
107.82	500.
122.77	600.
134.59	700.
144.13	800.
152.00	900.
158.60	1000.
164.20	1100.
168.97	1200.
173.08	1300.
176.62	1400.
179.69	1500.

Constant pressure heat capacity of gas

C_p,gas (J/mol*K)	Temperature (K)	Reference	Comment
70.29	317.25	Guthrie G.B., 1952	GT
80.12	358.20
90.00	402.20
99.58	449.20
106.48	487.20

Condensed phase thermochemistry data

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

Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_liquid			Ccb	Zaheeruddin and Lodhi, 1991	uncertain value: -55.36 kJ/mol; ALS
Δ_fH°_liquid	-62.34	kJ/mol	Ccb	Guthrie, Scott, et al., 1952	ALS
Δ_fH°_liquid	-57.45	kJ/mol	Ccb	Landrieu, Baylocq, et al., 1929	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid			Ccb	Zaheeruddin and Lodhi, 1991	uncertain value: -2090.36 kJ/mol; ALS
Δ_cH°_liquid	-2083.5	kJ/mol	Ccb	Guthrie, Scott, et al., 1952	Corresponding Δ_fHº_liquid = -62.17 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Δ_cH°_liquid	-2088.	kJ/mol	Ccb	Landrieu, Baylocq, et al., 1929	Corresponding Δ_fHº_liquid = -57.3 kJ/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity	Value	Units	Method	Reference	Comment
S°_liquid	176.65	J/mol*K	N/A	Guthrie, Scott, et al., 1952, 2	DH

Constant pressure heat capacity of liquid

C_p,liquid (J/mol*K)	Temperature (K)	Reference	Comment
114.56	298.15	Guthrie, Scott, et al., 1952, 2	T = 11 to 300 K.; DH

Gas phase ion energetics data

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

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
MM - Michael M. Meot-Ner (Mautner)
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 C₄H₄O⁺ (ion structure unspecified)

Quantity	Value	Units	Method	Reference	Comment
IE (evaluated)	8.88 ± 0.01	eV	N/A	N/A	L
Quantity	Value	Units	Method	Reference	Comment
Proton affinity (review)	803.4	kJ/mol	N/A	Hunter and Lias, 1998	HL
Quantity	Value	Units	Method	Reference	Comment
Gas basicity	770.9	kJ/mol	N/A	Hunter and Lias, 1998	HL

Proton affinity at 298K

Proton affinity (kJ/mol)	Reference	Comment
812. ± 8.	van Beelen, Koblenz, et al., 2004	T = 298K; PA derived by authors from GB with protonation entropy equated to Rlnσ(B)/σ(BH+); MM
813. ± 8.	van Beelen, Koblenz, et al., 2004	T = 298K; PA derived by authors from GB with protonation entropy equated to Rlnσ(B)/σ(BH+); MM

Gas basicity at 298K

Gas basicity (review) (kJ/mol)	Reference	Comment
781. ± 8.	van Beelen, Koblenz, et al., 2004	T = 298K; PA derived by authors from GB with protonation entropy equated to Rlnσ(B)/σ(BH+); MM
782. ± 8.	van Beelen, Koblenz, et al., 2004	T = 298K; PA derived by authors from GB with protonation entropy equated to Rlnσ(B)/σ(BH+); MM

Ionization energy determinations

IE (eV)	Method	Reference	Comment
8.9	PE	Klapstein, MacPherson, et al., 1990	LL
8.88	PE	Veszpremi, Nyulaszi, et al., 1987	LBLHLM
8.98 ± 0.03	EI	Arimura and Yoshikawa, 1984	LBLHLM
8.83	PE	Klasinc, Sabljic, et al., 1982	LBLHLM
8.87	PE	Kimura, Katsumata, et al., 1981	LLK
8.83	PE	Galasso, Klasinc, et al., 1981	LLK
8.88	PE	Willett and Baer, 1980	LLK
9.0 ± 0.1	CEMS	Tedder and Vidaud, 1980	LLK
8.88 ± 0.05	EI	Holmes and Terlouw, 1979	LLK
~8.8	EI	Van Veen, 1976	LLK
8.89	CTS	Aloisi, Santini, et al., 1975	LLK
8.85 ± 0.05	EI	Thorstad and Undheim, 1974	LLK
8.99 ± 0.05	EI	Linda, Marino, et al., 1971	LLK
8.883	PE	Derrick, Asbrink, et al., 1971	LLK
8.883	S	Derrick, Asbrink, et al., 1971	LLK
8.91 ± 0.01	PI	Potapov and Bazhenov, 1970	RDSH
8.87 ± 0.03	EI	Johnstone, Mellon, et al., 1970	RDSH
8.89 ± 0.05	PE	Baker, Betteridge, et al., 1970	RDSH
8.89 ± 0.01	PI	Watanabe, 1957	RDSH
8.90	PE	Zykov, Erchak, et al., 1983	Vertical value; LBLHLM
8.88	PE	Bock and Roth, 1983	Vertical value; LBLHLM
8.89	PE	Kobayashi, Kubota, et al., 1982	Vertical value; LBLHLM
8.89	PE	Bieri, Asbrink, et al., 1982	Vertical value; LBLHLM
8.88	PE	Schweig and Thiel, 1974	Vertical value; LLK

Appearance energy determinations

Ion	AE (eV)	Other Products	Method	Reference	Comment
CHO⁺	13.2 ± 0.1	C₃H₃	PE	Willett and Baer, 1980	LLK
CHO⁺	13.7 ± 0.1	C₃H₃	CEMS	Tedder and Vidaud, 1980	LLK
C₂HO⁺	12.5 ± 0.2	C₂H₃	CEMS	Tedder and Vidaud, 1980	LLK
C₂H₂O⁺	11.80 ± 0.10	C₂H₂	PE	Willett and Baer, 1980	LLK
C₃H₃⁺	12.10 ± 0.10	CHO	PE	Willett and Baer, 1980	LLK
C₃H₃⁺	12.8 ± 0.1	CHO	CEMS	Tedder and Vidaud, 1980	LLK
C₃H₄⁺	11.48 ± 0.05	CO	EI	Mommers, Burgers, et al., 1984	LBLHLM
C₃H₄⁺	11.60 ± 0.10	CO	PE	Willett and Baer, 1980	LLK
C₃H₄⁺	12.7 ± 0.1	CO	CEMS	Tedder and Vidaud, 1980	LLK

De-protonation reactions

C₄H₃O^- + = Furan

By formula: C₄H₃O^- + H⁺ = C₄H₄O

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1636.2 ± 1.5	kJ/mol	G+TS	Grabowski and Owusu	gas phase; B
Δ_rH°	1624. ± 13.	kJ/mol	G+TS	DePuy, Kass, et al., 1988	gas phase; Order:H2O < furan < 2-Me-furan < MeOH. D exchange indicates anion at C-2.; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1602.1 ± 0.84	kJ/mol	IMRE	Grabowski and Owusu	gas phase; B
Δ_rG°	1590. ± 13.	kJ/mol	IMRB	DePuy, Kass, et al., 1988	gas phase; Order:H2O < furan < 2-Me-furan < MeOH. D exchange indicates anion at C-2.; B

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Gas phase ion energetics data, Notes

Zaheeruddin and Lodhi, 1991
Zaheeruddin, M.; Lodhi, Z.H., Enthalpies of formation of some cyclic compounds, Phys. Chem. (Peshawar Pak.), 1991, 10, 111-118. [all data]

Guthrie, Scott, et al., 1952
Guthrie, G.B., Jr.; Scott, D.W.; Hubbard, W.N.; Katz, C.; McCullough, J.P.; Gross, M.E.; Williamson, K.D.; Waddington, G., Thermodynamic properties of furan, J. Am. Chem. Soc., 1952, 74, 4662-46. [all data]

Landrieu, Baylocq, et al., 1929
Landrieu, P.; Baylocq, F.; Johnson, J.R., Etude thermochimique dans la serie furanique, Bull. Soc. Chim. France, 1929, 45, 36-49. [all data]

Dorofeeva O.V., 1992
Dorofeeva O.V., Ideal gas thermodynamic properties of oxygen heterocyclic compounds. Part 1. Three-membered, four-membered and five-membered rings, Thermochim. Acta, 1992, 194, 9-46. [all data]

Guthrie G.B., 1952
Guthrie G.B., Jr., Thermodynamic properties of furan, J. Am. Chem. Soc., 1952, 74, 4662-4669. [all data]

Bak B., 1955
Bak B., Infrared absorption spectra of alpha and beta monodeutero, and alpha, alpha' dideutero furan vapors. Heat capacity and entropy of furan, Acta Chem. Scand., 1955, 9, 749-762. [all data]

Rico M., 1967
Rico M., Fundamental vibrations of furan and deuterated derivatives, J. Mol. Spectrosc., 1967, 24, 133-148. [all data]

Soptrajanov B., 1968
Soptrajanov B., Thermodynamic functions of furan and deuterated furans, Croat. Chem. Acta, 1968, 40, 241-245. [all data]

Chao J., 1986
Chao J., Thermodynamic properties of key organic oxygen compounds in the carbon range C1 to C4. Part 2. Ideal gas properties, J. Phys. Chem. Ref. Data, 1986, 15, 1369-1436. [all data]

Klots T.D., 1994
Klots T.D., Complete vapor phase assignment for the fundamental vibrations of furan, pyrrole and thiophene, Spectrochim. Acta, 1994, A50, 765-795. [all data]

Guthrie, Scott, et al., 1952, 2
Guthrie, G.B., Jr.; Scott, D.W.; Hubbard, W.N.; Katz, C.; McCullough, J.P.; Gross, M.E.; Williamson, K.D.; Waddington, G., Thermodynamic properties of furan, J. Am. Chem. Soc., 1952, 74, 4662-4669. [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]

van Beelen, Koblenz, et al., 2004
van Beelen, E.S.E.; Koblenz, T.A.; Ingemann, S.; Hammerum, S., Experimental and theoretical evaluation of proton affinities of furan, the methylphenols, and the related anisoles, J. Phys. Chem. A, 2004, 108, 2787. [all data]

Klapstein, MacPherson, et al., 1990
Klapstein, D.; MacPherson, C.D.; O'Brien, R.T., The photoelectron spectra and electronic structure of 2-carbonyl furans, Can. J. Chem., 1990, 68, 747. [all data]

Veszpremi, Nyulaszi, et al., 1987
Veszpremi, T.; Nyulaszi, L.; Nagy, J., Ultraviolet photoelectron spectroscopy and quantum-mechanical study of alkyl- and trimethylsilyl-furanes, J. Organomet. Chem., 1987, 331, 175. [all data]

Arimura and Yoshikawa, 1984
Arimura, M.; Yoshikawa, Y., Ionization efficiency and ionization energy of cyclic compounds by electron impact, Mass Spectrosc. (Tokyo), 1984, 32, 375. [all data]

Klasinc, Sabljic, et al., 1982
Klasinc, L.; Sabljic, A.; Kluge, G.; Rieger, J.; Scholz, M., Chemistry of excited states. Part 13. Assignment of lowest .PI.-ionizations in photoelectron spectra of thiophen, furan, and pyrrole, J. Chem. Soc. Perkin Trans. 2, 1982, 539. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Galasso, Klasinc, et al., 1981
Galasso, V.; Klasinc, L.; Sabluic, A.; Trinajstic, N.; Pappalardo, G.C.; Steglich, W., Conformation and photoelectron spectra of 2-(2-Furyl)pyrrole and 2-(2-tThienyl)pyrrole, J. Chem. Soc. Perkin Trans. 2, 1981, 127. [all data]

Willett and Baer, 1980
Willett, G.D.; Baer, T., Thermochemistry and dissociation dynamics of state-selected C₄H₄X ions. 2. Furan 3-butyn-2-one, J. Am. Chem. Soc., 1980, 102, 6769. [all data]

Tedder and Vidaud, 1980
Tedder, J.M.; Vidaud, P.H., Charge exchange mass spectra of thiophene, pyrrole and furan, J. Chem. Soc. Faraday Trans. 2, 1980, 76, 1516. [all data]

Holmes and Terlouw, 1979
Holmes, J.L.; Terlouw, J.K., Structures of [C₄H₄O]⁺ ions produced from 2- and 4-pyrone, J. Am. Chem. Soc., 1979, 101, 4973. [all data]

Van Veen, 1976
Van Veen, E.H., Triplet π-π^* transitions in thiophene, furan and pyrrole by low-energy electron-impact spectroscopy, Chem. Phys. Lett., 1976, 41, 535. [all data]

Aloisi, Santini, et al., 1975
Aloisi, G.; Santini, S.; Savelli, G., Molecular complexes of heteroaromatic five membered ring compounds with tetracyanoethylene. Charge transfer spectra, equilibrium constants and ionization potentials of the donors, J. Chem. Soc. Faraday Trans. 1, 1975, 70, 2045. [all data]

Thorstad and Undheim, 1974
Thorstad, O.; Undheim, K., Mass spectrometry of onium compounds. XXIV. Ionisation potential in structure analysis of pyridodiazo-oxides, Chem. Scr., 1974, 6, 222. [all data]

Linda, Marino, et al., 1971
Linda, P.; Marino, G.; Pignataro, S., A comparison of sensitivities to substituent effects of five- membered heteroaromatic rings in gas phase ionization, J. Chem. Soc. B, 1971, 1585. [all data]

Derrick, Asbrink, et al., 1971
Derrick, P.J.; Asbrink, L.; Edqvist, O.; Jonsson, B.-O.; Lindholm, E., Rydberg series in small molecules. X. Photoelectron spectroscopy and electronic structure of furan, Intern. J. Mass Spectrom. Ion Phys., 1971, 6, 161. [all data]

Potapov and Bazhenov, 1970
Potapov, V.K.; Bazhenov, B.A., The photionization of pyrrole, furan, and thiophene, High Energy Chem., 1970, 505, In original 553. [all data]

Johnstone, Mellon, et al., 1970
Johnstone, R.A.W.; Mellon, F.A.; Ward, S.D., Online acquisition of ionization efficiency data, Intern. J. Mass Spectrom. Ion Phys., 1970, 5, 241. [all data]

Baker, Betteridge, et al., 1970
Baker, A.D.; Betteridge, D.; Kemp, N.R.; Kirby, R.E., Application of photoelectron spectrometry to pesticide analysis. Photoelectron spectra of fivemembered heterocycles and related molecules, Anal. Chem., 1970, 42, 1064. [all data]

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Zykov, Erchak, et al., 1983
Zykov, B.G.; Erchak, N.P.; Khvostenko, V.I.; Lukevits, E.; Matorykina, V.F.; Asfandiarov, N.L., Photoelectron spectra of furylsilanes and their carbon analogs, J. Organomet. Chem., 1983, 253, 301. [all data]

Bock and Roth, 1983
Bock, H.; Roth, B., Radical ions. 49. Redox reactions of some thiophene derivatives, Phosphorus Sulfur, 1983, 14, 211. [all data]

Kobayashi, Kubota, et al., 1982
Kobayashi, T.; Kubota, T.; Ezumi, K.; Utsunomiya, C., Photoelectron angular distribution study of some isoxazoles combined with perturbation theoretic approach, Bull. Chem. Soc. Jpn., 1982, 55, 3915. [all data]

Bieri, Asbrink, et al., 1982
Bieri, G.; Asbrink, L.; Von Niessen, W., 30.4-nm He(II) photoelectron spectra of organic molecules, J. Electron Spectrosc. Relat. Phenom., 1982, 27, 129. [all data]

Schweig and Thiel, 1974
Schweig, A.; Thiel, W., Photoionization cross sections: He I- and He II-photoelectron spectra of homologous oxygen and sulphur compounds, Mol. Phys., 1974, 27, 265. [all data]

Mommers, Burgers, et al., 1984
Mommers, A.A.; Burgers, P.C.; Holmes, J.L.; Terlouw, J.K., Isomeric [C₃H₄]⁺ ions: Their identification and generation in dissociative ionizations, Org. Mass Spectrom., 1984, 19, 7. [all data]

Grabowski and Owusu
Grabowski, J.J.; Owusu, D., , as cited in 98CLI/WEN. [all data]

DePuy, Kass, et al., 1988
DePuy, C.H.; Kass, S.R.; Bean, G.P., Formation and Reactions of Heteroaromatic Anions in the Gas Phase, J. Org. Chem., 1988, 53, 19, 4427, https://doi.org/10.1021/jo00254a001 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Gas phase ion energetics data, References

Symbols used in this document:

AE	Appearance energy
C_p,gas	Constant pressure heat capacity of gas
C_p,liquid	Constant pressure heat capacity of liquid
IE (evaluated)	Recommended ionization energy
S°_liquid	Entropy of liquid at standard conditions
Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_liquid	Enthalpy of formation of liquid 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
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.