Azulene

Azulene
Names
	Preferred IUPAC name Azulene
	Systematic IUPAC name Bicyclo[5.3.0]decapentaene
Identifiers
CAS Number	275-51-4 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:31249 ;
ChemSpider	8876 ;
ECHA InfoCard	100.005.449
KEGG	C13392 ;
PubChem CID	9231;
UNII	82R6M9MGLP ;
CompTox Dashboard (EPA)	DTXSID2059770 ;
	InChI InChI=1S/C10H8/c1-2-5-9-7-4-8-10(9)6-3-1/h1-8H Key: CUFNKYGDVFVPHO-UHFFFAOYSA-N ; InChI=1/C10H8/c1-2-5-9-7-4-8-10(9)6-3-1/h1-8H Key: CUFNKYGDVFVPHO-UHFFFAOYAT;
	SMILES c1cccc2cccc2c1;
Properties
Chemical formula	C10H8
Molar mass	128.174 g·mol−1
Melting point	99 to 100 °C (210 to 212 °F; 372 to 373 K)
Boiling point	242 °C (468 °F; 515 K)
Magnetic susceptibility (χ)	-98.5·10−6 cm3/mol g/L
Thermochemistry
Std enthalpy of; combustion (ΔcH⦵298)	−1266.5 kcal/mol
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Azulene is an aromatic organic compound and an isomer of naphthalene. Naphthalene is colourless, whereas azulene is dark blue. The compound is named after its colour, as "azul" is Spanish for blue. Two terpenoids, vetivazulene (4,8-dimethyl-2-isopropylazulene) and guaiazulene (1,4-dimethyl-7-isopropylazulene), that feature the azulene skeleton are found in nature as constituents of pigments in mushrooms, guaiac wood oil, and some marine invertebrates.

Azulene has a long history, dating back to the 15th century as the azure-blue chromophore obtained by steam distillation of German chamomile. The chromophore was discovered in yarrow and wormwood and named in 1863 by Septimus Piesse. Its structure was first reported by Lavoslav Ružička, followed by its organic synthesis in 1937 by Placidus Plattner.

^ International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 207. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
^ Sweet, L. I.; Meier, P. G. (1997). "Lethal and Sublethal Effects of Azulene and Longifolene to Microtox®, Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas" (PDF). Bulletin of Environmental Contamination and Toxicology. 58 (2): 268–274. Bibcode:1997BuECT..58..268S. doi:10.1007/s001289900330. hdl:2027.42/42354. PMID 8975804.
^ Salter, Carl; Foresman, James B. (1998). "Naphthalene and Azulene I: Semimicro Bomb Calorimetry and Quantum Mechanical Calculations". Journal of Chemical Education. 75 (10): 1341. Bibcode:1998JChEd..75.1341S. doi:10.1021/ed075p1341.

[1] International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 207. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.

[2] Sweet, L. I.; Meier, P. G. (1997). "Lethal and Sublethal Effects of Azulene and Longifolene to Microtox®, Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas" (PDF). Bulletin of Environmental Contamination and Toxicology. 58 (2): 268–274. Bibcode:1997BuECT..58..268S. doi:10.1007/s001289900330. hdl:2027.42/42354. PMID 8975804.

[3] Salter, Carl; Foresman, James B. (1998). "Naphthalene and Azulene I: Semimicro Bomb Calorimetry and Quantum Mechanical Calculations". Journal of Chemical Education. 75 (10): 1341. Bibcode:1998JChEd..75.1341S. doi:10.1021/ed075p1341.

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