Title: Geosmin
CAS Registry Number: 19700-21-1
CAS Name: [4S-(4a,4aa,8ab)]-Octahydro-4,8a-dimethyl-4a(2H)-naphthalenol
Additional Names: octahydro-4a,8ab-dimethyl-4aa(2H)-naphthol; 1,10-trans-dimethyl-trans-(9)-decalol
Molecular Formula: C12H22O
Molecular Weight: 182.30
Percent Composition: C 79.06%, H 12.16%, O 8.78%
Literature References: Major volatile component of beet essence, also determined to be the potent earthy odor contaminant of fish, beans, water: A. C. Thaysen, Ann. Appl. Biol. 23, 99 (1936); J. Silvey, A. W. Roach, J. Am. Water Works Assoc. 56, 60 (1964); A. A. Rosen et al., Water Treat. Exam. 19 (Pt. 2), 106 (1970); R. G. Buttery et al., J. Agric. Food Chem. 24, 419, 1246 (1976). Isoln from Actinomyetes, algae: N. N. Gerber, H. A. Lechevalier, Appl. Microbiol. 13, 935 (1965); A. A. Rosen et al., ibid. 16, 178 (1968); R. S. Safferman et al., Environ. Sci. Technol. 1, 429 (1967). Isoln from beets: K. E. Murray, P. A. Bannister, Chem. Ind. (London) 1975, 973; L. D. Tyler et al., J. Agric. Food Chem. 26, 1466 (1978). Structure: N. N. Gerber, Biotechnol. Bioeng. 9, 321 (1967); eidem, Tetrahedron Lett. 1968, 2971. Biological degradation: L. V. Narayan, W. J. Nunez, J. Am. Water Works Assoc. 66 (Pt. 1), 532 (1974).
Properties: Colorless neutral oil, bp 270°. [a]D25 -16.5°. Threshold odor conc: 0.1 ppb. Decomp in acid to odorless compds.
Boiling point: bp 270°
Optical Rotation: [a]D25 -16.5°
Gepefrine Gephyrotoxin Geraniol Geranium Geranylhydroquinone

CAS number 19700-21-1 YesY
PubChem 29746
ChemSpider 27642 YesY
ChEBI CHEBI:46702 YesY
Jmol-3D images Image 1
Molecular formula C12H22O
Molar mass 182.30 g mol−1
Boiling point 270 to 271 °C; 518 to 520 °F; 543 to 544 K
Flash point 104 °C; 219 °F; 377 K
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Geosmin is an organic compound with a distinct earthy flavor and aroma, and is responsible for the earthy taste of beets and a contributor to the strong scent (petrichor) that occurs in the air when rain falls after a dry spell of weather or when soil is disturbed. It is produced by a type of Actinobacteria. In chemical terms, it is a bicyclic alcohol with formula C12H22O, a derivative of decalin. Its name is derived from the Greek γεω- "earth" and ὀσμή "smell".