Isoxazole

Formula: C₃H₃NO
Molecular weight: 69.0620
IUPAC Standard InChI: InChI=1S/C3H3NO/c1-2-4-5-3-1/h1-3H
IUPAC Standard InChIKey: CTAPFRYPJLPFDF-UHFFFAOYSA-N
CAS Registry Number: 288-14-2
Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Other names: 1-Oxa-2-azacyclopentadiene; Isooxazole
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Gas phase thermochemistry data

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Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_gas	82.0 ± 0.6	kJ/mol	Ccr	Steele, Chirico, et al., 1996
Δ_fH°_gas	78.58 ± 0.54	kJ/mol	Ccb	McCormick and Hamilton, 1978	see McCormick, 1977

Condensed phase thermochemistry data

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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	44.78 ± 0.56	kJ/mol	Ccr	Steele, Chirico, et al., 1996	ALS
Δ_fH°_liquid	42.13 ± 0.54	kJ/mol	Ccb	McCormick and Hamilton, 1978	see McCormick, 1977; ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-1654.05 ± 0.32	kJ/mol	Ccr	Steele, Chirico, et al., 1996	ALS
Δ_cH°_liquid	-1651.4 ± 0.50	kJ/mol	Ccb	McCormick and Hamilton, 1978	see McCormick, 1977; ALS

Constant pressure heat capacity of liquid

C_p,liquid (J/mol*K)	Temperature (K)	Reference	Comment
108.1	298.15	Steele, Chirico, et al., 1993	DH

Phase change data

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Data compiled as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
AC - William E. Acree, Jr., James S. Chickos

Quantity	Value	Units	Method	Reference	Comment
T_boil	367.2	K	N/A	Aldrich Chemical Company Inc., 1990	BS
T_boil	368.7	K	N/A	Weast and Grasselli, 1989	BS
Quantity	Value	Units	Method	Reference	Comment
T_c	590.	K	N/A	Steele, Chirico, et al., 1996, 2	Uncertainty assigned by TRC = 3. K; fitting parameter in Wagner equation for vapor pressure; TRC
Quantity	Value	Units	Method	Reference	Comment
P_c	61.00	bar	N/A	Steele, Chirico, et al., 1996, 2	Uncertainty assigned by TRC = 4.00 bar; from extrapolation of obs. vapor pressure to Tc; TRC
Quantity	Value	Units	Method	Reference	Comment
ρ_c	5.237	mol/l	N/A	Steele, Chirico, et al., 1996, 2	Uncertainty assigned by TRC = 0.29 mol/l; TRC
Quantity	Value	Units	Method	Reference	Comment
Δ_vapH°	37.24 ± 0.22	kJ/mol	V	Steele, Chirico, et al., 1996	ALS
Δ_vapH°	37.2 ± 0.2	kJ/mol	EB	Steele, Chirico, et al., 1996	Based on data from 314. to 404. K.; AC
Δ_vapH°	36.4 ± 0.04	kJ/mol	C	McCormick and Hamilton, 1978	see McCormick, 1977; ALS
Δ_vapH°	36.5 ± 0.1	kJ/mol	C	McCormick and Hamilton, 1978	AC

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:

Gas Chromatography

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Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Kovats' RI, non-polar column, isothermal

View large format table.

Column type	Active phase	Temperature (C)	I	Reference	Comment
Capillary	OV-101	110.	590.	Zhuravleva, 2000	50. m/0.3 mm/0.4 μm, He
Capillary	OV-101	110.	590.	Golovnya, Kuz'menko, et al., 1999	50. m/0.3 mm/0.4 μm, He

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Gas Chromatography, Notes

Steele, Chirico, et al., 1996
Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Smith, N.K.; Tasker, I.R., Thermodynamic properties and ideal-gas enthalpies of formation for cyclohexene, phthalan (2,5-dihydrobenzo-3,4-furan), isoxazole, octylamine, dioctylamine, trioctylamine, phenyl isocyanate, and 1,4,5,6-tetrahydropyrimidine, J. Chem. Eng. Data, 1996, 41, 1269-1284. [all data]

McCormick and Hamilton, 1978
McCormick, D.G.; Hamilton, W.S., The enthalpies of combustion and formation of oxazole and isoxazole, J. Chem. Thermodyn., 1978, 10, 275-278. [all data]

McCormick, 1977
McCormick, D.G., The resonance energies of oxazole and isoxazole determined from the enthalpies of combustion and formation (Order No. 7801771), Diss. Abstr. Int. B, 1977, 38, 4271. [all data]

Steele, Chirico, et al., 1993
Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Tasker, I.R., Determination of ideal gas enthalpies of formation for key compounds the 1991 project results, DIPPR Project, 1993, 871, NIPER-716. [all data]

Aldrich Chemical Company Inc., 1990
Aldrich Chemical Company Inc., Catalog Handbook of Fine Chemicals, Aldrich Chemical Company, Inc., Milwaukee WI, 1990, 1. [all data]

Weast and Grasselli, 1989
CRC Handbook of Data on Organic Compounds, 2nd Editon, Weast,R.C and Grasselli, J.G., ed(s)., CRC Press, Inc., Boca Raton, FL, 1989, 1. [all data]

Steele, Chirico, et al., 1996, 2
Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Smith, N.K.; Tasker, I.R., Thermodynamic Properties and Ideal-Gas Enthalpies of Formation for Dioctylamine, trioctylamine, Phenyl Isocyanate, and 1,4,5,6-Tetrahydropyrimidine, J. Chem. Eng. Data, 1996, 41, 1269-84. [all data]

Zhuravleva, 2000
Zhuravleva, I.L., Evaluation of the polarity and boiling points of nitrogen-containing heterocyclic compounds by gas chromatography, Russ. Chem. Bull. (Engl. Transl.), 2000, 49, 2, 325-328, https://doi.org/10.1007/BF02494682 . [all data]

Golovnya, Kuz'menko, et al., 1999
Golovnya, R.V.; Kuz'menko, T.E.; Zhuravleva, I.L., Gas chromatographic indicator of the ability of five- and six-membered heterocyclic nitrogen-containing compounds for self-association in pure liquids, Russ. Chem. Bull. (Engl. Transl.), 1999, 48, 4, 726-729, https://doi.org/10.1007/BF02496256 . [all data]

Notes

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Symbols used in this document:

C_p,liquid	Constant pressure heat capacity of liquid
P_c	Critical pressure
T_boil	Boiling point
T_c	Critical temperature
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_vapH°	Enthalpy of vaporization at standard conditions
ρ_c	Critical density

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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