1H-Indazole

Formula: C₇H₆N₂
Molecular weight: 118.1359
IUPAC Standard InChI: InChI=1S/C7H6N2/c1-2-4-7-6(3-1)5-8-9-7/h1-5H,(H,8,9)
IUPAC Standard InChIKey: BAXOFTOLAUCFNW-UHFFFAOYSA-N
CAS Registry Number: 271-44-3
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: Isoindazole; 1,2-Diazaindene; 1H-Benzopyrazole; 2-Azaindole; Indazole; Benzopyrazole
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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	243.0 ± 1.3	kJ/mol	Ccb	Jimenez, Roux, et al., 1987	see Jimenez, Roux, et al., 1986
Δ_fH°_gas	254.2 ± 4.6	kJ/mol	Ccb	Faour and Akasheh, 1985

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°_solid	151.9 ± 1.3	kJ/mol	Ccb	Jimenez, Roux, et al., 1987	see Jimenez, Roux, et al., 1986; ALS
Δ_fH°_solid	166.5 ± 3.7	kJ/mol	Ccb	Faour and Akasheh, 1985	ALS
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_solid	-3764.0 ± 0.9	kJ/mol	Ccb	Jimenez, Roux, et al., 1987	see Jimenez, Roux, et al., 1986; ALS
Δ_cH°_solid	-3778.6 ± 3.5	kJ/mol	Ccb	Faour and Akasheh, 1985	ALS
Δ_cH°_solid	-3764.	kJ/mol	Ccb	Zimmerman and Geisenfelder, 1961	ALS

Constant pressure heat capacity of solid

C_p,solid (J/mol*K)	Temperature (K)	Reference	Comment
128.8	298.15	Jimenez, Roux, et al., 1987	Cp given as 1.09 J K-1 g-1.; 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
DRB - Donald R. Burgess, Jr.
AC - William E. Acree, Jr., James S. Chickos

Quantity	Value	Units	Method	Reference	Comment
T_fus	419.3	K	N/A	Rondestvedt and Blanchard, 1955	Uncertainty assigned by TRC = 0.6 K; TRC
Quantity	Value	Units	Method	Reference	Comment
Δ_subH°	91.1 ± 0.2	kJ/mol	V	Jimenez, Roux, et al., 1987	see Jimenez, Roux, et al., 1986; ALS
Δ_subH°	91.1	kJ/mol	N/A	Jimenez, Roux, et al., 1987	DRB
Δ_subH°	91.1 ± 0.2	kJ/mol	N/A	Jimenez, Roux, et al., 1987	See also Jimenez, Roux, et al., 1986, 2.; AC
Δ_subH°	87.7	kJ/mol	N/A	Faour and Akasheh, 1985	DRB
Δ_subH°	97.1	kJ/mol	V	Zimmerman and Geisenfelder, 1961	ALS

Reduced pressure boiling point

T_boil (K)	Pressure (bar)	Reference	Comment
543.2	0.991	Aldrich Chemical Company Inc., 1990	BS

Enthalpy of sublimation

Δ_subH (kJ/mol)	Temperature (K)	Method	Reference	Comment
90.9 ± 0.2	318.	ME	Jimenez, Roux, et al., 1987	Based on data from 308. to 317. K.; 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:

Reaction thermochemistry data

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Data compiled by: John E. Bartmess

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Individual Reactions

C₇H₅N₂^- + = 1H-Indazole

By formula: C₇H₅N₂^- + H⁺ = C₇H₆N₂

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	1457. ± 8.8	kJ/mol	G+TS	Catalan, Claramunt, et al., 1988	gas phase
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	1425. ± 8.4	kJ/mol	IMRE	Catalan, Claramunt, et al., 1988	gas phase

References

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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]

Faour and Akasheh, 1985
Faour, M.; Akasheh, T.S., Heat of combustion of some N-heterocycle compounds. Part 1, J. Chem. Soc. Perkin Trans. 2, 1985, 811-713. [all data]

Zimmerman and Geisenfelder, 1961
Zimmerman, H.; Geisenfelder, H., Uber die Mesomerieenergie von Azolen, Z. Electrochem., 1961, 65, 368-371. [all data]

Rondestvedt and Blanchard, 1955
Rondestvedt, C.S.; Blanchard, H.S., Arylation of Unsaturated Systems by Free Radicals I. Arylation of Alkylbenzenes, J. Am. Chem. Soc., 1955, 77, 1769. [all data]

Jimenez, Roux, et al., 1986, 2
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. [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]

Catalan, Claramunt, et al., 1988
Catalan, J.; Claramunt, R.M.; Elguero, J.; Menedez, M.; Anvia, F.; Quian, J.H.; Taagepera, M.; Taft, R.W., Basicity and Acidity of Azoles. The Annelation Effect in Azoles., J. Am. Chem. Soc., 1988, 110, 13, 4107, https://doi.org/10.1021/ja00221a001 . [all data]

Notes

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Symbols used in this document:

C_p,solid	Constant pressure heat capacity of solid
T_boil	Boiling point
T_fus	Fusion (melting) point
Δ_cH°_solid	Enthalpy of combustion of solid at standard conditions
Δ_fH°_gas	Enthalpy of formation of gas at standard conditions
Δ_fH°_solid	Enthalpy of formation of solid at standard conditions
Δ_rG°	Free energy of reaction at standard conditions
Δ_rH°	Enthalpy of reaction at standard conditions
Δ_subH	Enthalpy of sublimation
Δ_subH°	Enthalpy of sublimation at standard conditions

Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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