1H-Pyrazole
- Formula: C3H4N2
- Molecular weight: 68.0773
- IUPAC Standard InChIKey: WTKZEGDFNFYCGP-UHFFFAOYSA-N
- CAS Registry Number: 288-13-1
- 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: Pyrazole; 1,2-Diazole
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Gas phase thermochemistry data
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
DRB - Donald R. Burgess, Jr.
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°gas | 42.40 | kcal/mol | N/A | Zaheeruddin and Lodhi, 1991 | Value computed using ΔfHsolid° value of 112.4 kj/mol from Zaheeruddin and Lodhi, 1991 and ΔsubH° value of 65.0 kj/mol from Jimenez, Roux, et al., 1987.; DRB |
ΔfH°gas | 42.9 ± 0.2 | kcal/mol | Ccb | Jimenez, Roux, et al., 1987 | see Jimenez, Roux, et al., 1986; ALS |
ΔfH°gas | 43.3 ± 2.1 | kcal/mol | Ccb | Bedford, Edmondson, et al., 1962 | ALS |
Reaction thermochemistry data
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
B - John E. Bartmess
RCD - Robert C. Dunbar
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.
Individual Reactions
C3H3N2- + =
By formula: C3H3N2- + H+ = C3H4N2
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 353.6 ± 2.4 | kcal/mol | G+TS | Gianola, Ichino, et al., 2006 | gas phase; B |
ΔrH° | 353.6 ± 2.4 | kcal/mol | G+TS | Taft, Anvia, et al., 1986 | gas phase; value altered from reference due to change in acidity scale; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 346.4 ± 2.3 | kcal/mol | N/A | Gianola, Ichino, et al., 2006 | gas phase; B |
ΔrG° | 346.4 ± 2.3 | kcal/mol | IMRE | Taft, Anvia, et al., 1986 | gas phase; value altered from reference due to change in acidity scale; B |
By formula: Li+ + C3H4N2 = (Li+ • C3H4N2)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 44.7 ± 4.0 | kcal/mol | CIDT | Huang and Rodgers, 2002 | RCD |
By formula: Na+ + C3H4N2 = (Na+ • C3H4N2)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 30.6 ± 2.2 | kcal/mol | CIDT | Huang and Rodgers, 2002 | RCD |
By formula: K+ + C3H4N2 = (K+ • C3H4N2)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 20.0 ± 0.8 | kcal/mol | CIDT | Huang and Rodgers, 2002 | RCD |
IR Spectrum
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: Coblentz Society, Inc.
Condensed Phase Spectrum
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Notice: Except where noted, spectra from this collection were measured on dispersive instruments, often in carefully selected solvents, and hence may differ in detail from measurements on FTIR instruments or in other chemical environments. More information on the manner in which spectra in this collection were collected can be found here.
Notice: Concentration information is not available for this spectrum and, therefore, molar absorptivity values cannot be derived.
Additional Data
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Owner | COBLENTZ SOC. Collection (C) 2018 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
---|---|
Origin | DOW CHEMICAL COMPANY |
Source reference | COBLENTZ NO. 06435 |
Date | 1965/06/09 |
Name(s) | 1H-pyrazole |
State | SOLUTION (5% CCl4 FOR 3800-1335, 5% CS2 FOR 1335-400) |
Instrument | BECKMAN IR-9 (GRATING) |
Instrument parameters | ORDER CHANGES: 670, 1200, 2000 CM-1 |
Path length | 0.011 CM, 0.012 CM SPECTRAL CONTAMINATION DUE TO CCl4 AROUND 1555, AND AN UNKNOWN AROUND 400 CM-1 |
Resolution | 2 |
Sampling procedure | TRANSMISSION |
Data processing | DIGITIZED BY COBLENTZ SOCIETY (BATCH I) FROM HARD COPY |
Melting point | 70 C |
Mass spectrum (electron ionization)
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
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Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
---|---|
Origin | Japan AIST/NIMC Database- Spectrum MS-NW-5084 |
NIST MS number | 230189 |
UV/Visible spectrum
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Spectrum
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Additional Data
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Source | Knowles and Elguero, 1967 |
---|---|
Owner | INEP CP RAS, NIST OSRD Collection (C) 2007 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
Origin | INSTITUTE OF ENERGY PROBLEMS OF CHEMICAL PHYSICS, RAS |
Source reference | RAS UV No. 19851 |
Instrument | Cary 11 |
Melting point | 70 |
Gas Chromatography
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Kovats' RI, non-polar column, isothermal
Column type | Active phase | Temperature (C) | I | Reference | Comment |
---|---|---|---|---|---|
Capillary | OV-101 | 110. | 864. | Zhuravleva, 2000 | 50. m/0.3 mm/0.4 μm, He |
Capillary | OV-101 | 110. | 864. | Golovnya, Kuz'menko, et al., 1999 | 50. m/0.3 mm/0.4 μm, He |
Van Den Dool and Kratz RI, non-polar column, temperature ramp
Column type | Active phase | I | Reference | Comment |
---|---|---|---|---|
Packed | SE-30 | 837. | Peng, Ding, et al., 1988 | He, Supelcoport and Chromosorb, 40. C @ 4. min, 10. K/min, 250. C @ 60. min; Column length: 3.05 m |
References
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
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]
Jimenez, Roux, et al., 1987
Jimenez, P.; Roux, M.V.; Turrion, C.,
Thermochemical properties of N-heterocyclic compounds. I. Enthalpies of combustion, vapour pressures and enthalpies of sublimation, and enthalpies of formation of pyrazole, imidazole, indazole, and benzimidazole,
J. Chem. Thermodyn., 1987, 19, 985-992. [all data]
Jimenez, Roux, et al., 1986
Jimenez, P.; Roux, M.V.; Turrion, C.; Gomis, F.,
Thermochemical properties of some N-heterocyclic compounds,
J. Calorim. Anal. Therm. Thermodyn. Chim., 1986, 17, 469-470. [all data]
Bedford, Edmondson, et al., 1962
Bedford, A.F.; Edmondson, P.B.; Mortimer, C.T.,
Heats of formation and bond energies. Part VI. n-Butyliso-butyraldimine, n-butylisobutylamine, pyrazole, and imidazole,
J. Chem. Soc., 1962, 2927-2931. [all data]
Gianola, Ichino, et al., 2006
Gianola, A.J.; Ichino, T.; Kato, S.; Bierbaum, V.M.; Lineberger, W.C.,
Thermochemical studies of pyrazolide,
J. Phys. Chem. A, 2006, 110, 27, 8457-8466, https://doi.org/10.1021/jp057499+
. [all data]
Taft, Anvia, et al., 1986
Taft, R.W.; Anvia, F.; Taagepera, M.; Catalan, J.; Elgueroy, J.,
Electrostatic proximity effects in the relative basicities of pyrazole, imidazole, pyridazine, and pyrimidine,
J. Am. Chem. Soc., 1986, 108, 3237. [all data]
Huang and Rodgers, 2002
Huang, H.; Rodgers, M.T.,
Sigma versus Pi interactions in alkali metal ion binding to azoles: Threshold collision-induced dissociation and ab initio theory studies,
J. Phys. Chem. A, 2002, 106, 16, 4277, https://doi.org/10.1021/jp013630b
. [all data]
Knowles and Elguero, 1967
Knowles, A.; Elguero, J.,
UV atlas of organic compounds, 1967, 3, G1/6. [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]
Peng, Ding, et al., 1988
Peng, C.T.; Ding, S.F.; Hua, R.L.; Yang, Z.C.,
Prediction of Retention Indexes I. Structure-Retention Index Relationship on Apolar Columns,
J. Chromatogr., 1988, 436, 137-172, https://doi.org/10.1016/S0021-9673(00)94575-8
. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, References
- Symbols used in this document:
ΔfH°gas Enthalpy of formation of gas at standard conditions ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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