Azulene

Formula: C₁₀H₈
Molecular weight: 128.1705
IUPAC Standard InChI: InChI=1S/C10H8/c1-2-5-9-7-4-8-10(9)6-3-1/h1-8H
IUPAC Standard InChIKey: CUFNKYGDVFVPHO-UHFFFAOYSA-N
CAS Registry Number: 275-51-4
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: Bicyclo[5.3.0]decapentaene; Cyclopentacycloheptene; Azunamic; Bicyclo(5.3.0)-1,3,5,7,9-decapentaene; Bicyclo(0.3.5)deca-1,3,5,7,9-pentaene; BICYCLO(5.3.0)-DECA-2,4,6,8,10-PENTAENE; Azusalen [as sodium sulfonate]
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:
Options:
- Switch to SI units

Data at NIST subscription sites:

NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

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, Reaction thermochemistry data, References, Notes

Data compiled as indicated in comments:
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	73.5	kcal/mol	Chyd	Roth, Bohm, et al., 1983	ALS
Δ_fH°_gas	66.9	kcal/mol	Ccb	Kovats, Gunthard, et al., 1957	Correction to Kovats, Gunthard, et al., 1955; ALS

Constant pressure heat capacity of gas

C_p,gas (cal/mol*K)	Temperature (K)	Reference	Comment
19.59	200.	Kovats E., 1955	GT
30.691	298.15
30.930	300.
42.151	400.
51.690	500.
59.319	600.
65.559	700.
70.590	800.
74.749	900.
78.241	1000.

Condensed phase thermochemistry data

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

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

Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_liquid	-1265.1 ± 0.6	kcal/mol	Ccb	Quitzsch, Schaffernicht, et al., 1963	Corresponding Δ_fHº_liquid = 51.3 kcal/mol (simple calculation by NIST; no Washburn corrections)
Quantity	Value	Units	Method	Reference	Comment
Δ_fH°_solid	50.7	kcal/mol	Ccb	Kovats, Gunthard, et al., 1957	Correction to Kovats, Gunthard, et al., 1955
Quantity	Value	Units	Method	Reference	Comment
Δ_cH°_solid	-1264.5	kcal/mol	Ccb	Kovats, Gunthard, et al., 1957	Correction to Kovats, Gunthard, et al., 1955; Corresponding Δ_fHº_solid = 50.7 kcal/mol (simple calculation by NIST; no Washburn corrections)

Reaction thermochemistry data

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

Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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

C₁₀H₇^- + = Azulene

By formula: C₁₀H₇^- + H⁺ = C₁₀H₈

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	367.7 ± 2.5	kcal/mol	TDEq	Meot-ner, Liebman, et al., 1988	gas phase; Acidity seriously disagrees with high level calculations. Dissociative to acetylide? C-3is most acidic site by G3MP2B3 calns.; B
Quantity	Value	Units	Method	Reference	Comment
Δ_rG°	360.2 ± 2.0	kcal/mol	TDEq	Meot-ner, Liebman, et al., 1988	gas phase; Acidity seriously disagrees with high level calculations. Dissociative to acetylide? C-3is most acidic site by G3MP2B3 calns.; B

C₆H₇N⁺ + Azulene = (C₆H₇N⁺ • Azulene )

By formula: C₆H₇N⁺ + C₁₀H₈ = (C₆H₇N⁺ • C₁₀H₈)

Bond type: Charge transfer bond (positive ion)

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	14.0	kcal/mol	PHPMS	Meot-Ner (Mautner) and El-Shall, 1986	gas phase; Entropy change calculated or estimated; M
Quantity	Value	Units	Method	Reference	Comment
Δ_rS°	26.	cal/mol*K	N/A	Meot-Ner (Mautner) and El-Shall, 1986	gas phase; Entropy change calculated or estimated; M

Free energy of reaction

Δ_rG° (kcal/mol)	T (K)	Method	Reference	Comment
5.8	315.	PHPMS	Meot-Ner (Mautner) and El-Shall, 1986	gas phase; Entropy change calculated or estimated; M

5 + Azulene =

By formula: 5H₂ + C₁₀H₈ = C₁₀H₁₈

Quantity	Value	Units	Method	Reference	Comment
Δ_rH°	-98.98 ± 0.13	kcal/mol	Chyd	Turner, Meador, et al., 1957	liquid phase; solvent: Acetic acid; ALS

References

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

Roth, Bohm, et al., 1983
Roth, W.R.; Bohm, M.; Lenhartz, H-W.; Vogel, E., Heats of hydrogenation. Part 5. Resonance energy of bridged [10]annulenes, Angew. Chem., 1983, 95, 1011-1012. [all data]

Kovats, Gunthard, et al., 1957
Kovats, E.; Gunthard, H.; Plattner, A., Die tabellen 4 und 5 enthalten numerische fehler und lanten richtig, Helv. Chim. Acta, 1957, 40, 000. [all data]

Kovats, Gunthard, et al., 1955
Kovats, E.; Gunthard, Hs.H.; Plattner, Pl.A., Thermische eigenschaften von azulenen, Helv. Chim. Acta, 1955, 38, 1912-1919. [all data]

Kovats E., 1955
Kovats E., Thermochemical properties of azulene, Helv. Chim. Acta, 1955, 38, 1912-1919. [all data]

Quitzsch, Schaffernicht, et al., 1963
Quitzsch, K.; Schaffernicht, H.; Geiseler, G., Uber ein Mikro-Metallblock-Kalorimeter, Z. Phys. Chem. (Leipzig), 1963, 223, 200-206. [all data]

Meot-ner, Liebman, et al., 1988
Meot-ner, M.; Liebman, J.F.; Kafafi, S.A., Ionic Probes of Aromaticity in Annelated Rings, J. Am. Chem. Soc., 1988, 110, 18, 5937, https://doi.org/10.1021/ja00226a001 . [all data]

Meot-Ner (Mautner) and El-Shall, 1986
Meot-Ner (Mautner), M.; El-Shall, M.S., Ionic Charge Transfer Complexes. 1. Cationic Complexes with Delocalized and Partially Localized pi Systems, J. Am. Chem. Soc., 1986, 108, 15, 4386, https://doi.org/10.1021/ja00275a026 . [all data]

Turner, Meador, et al., 1957
Turner, R.B.; Meador, W.R.; Doering, W.E.; Knox, L.H.; Mayer, J.R.; Wiley, D.W., Heats of hydrogenation. III. Hydrogenation of cycllooctatetraene and of some seven-membered non-benzenoid aromatic compounds, J. Am. Chem. Soc., 1957, 79, 4127-4133. [all data]

Notes

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

Symbols used in this document:

C_p,gas	Constant pressure heat capacity of gas
T	Temperature
Δ_cH°_liquid	Enthalpy of combustion of liquid at standard conditions
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_rS°	Entropy 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.