Compounds · Alcohols · Microbial origin
2-Methylisoborneol
Also known as MIB — an analysis may use any of these names
Damp earth, mould, dark cellar. Together with geosmin it builds the smell of first rain.
- CAS
- 2371-42-8
- Formula
- C11H20O
- Molar mass
- 168.28
- Odour threshold
- 0.015 ppbin water
- Boiling point
- ≈ 207 °C estimated
For this compound the two axes sit close together. Volatility tells you whether it leaves a surface early or late; the threshold tells you how much of it the nose needs before it notices.
Where it comes from
Biosynthetic pathway: Microbial origin — made by bacteria and yeasts, not by plants.
About the threshold figure
In the same extremely potent group as geosmin, and likewise produced by microorganisms in soil and water.
Published thresholds differ by several orders of magnitude, because of differences in measuring method, sample purity and panel. The figure here is an order of magnitude for relative comparison, not a measurement. We give it only for compounds where the literature broadly agrees — 52 of the 106 compounds in the library. The rest are left blank rather than guessed.
Why it sits where it does
A rather bulky bicyclic alcohol; its hydroxyl group is partly shielded, so it boils lower than its mass would suggest.
Where else you meet it
Damp earth, tap water with algae, and fish farmed in stagnant ponds.
Dictionary entries that mention this compound
About the boiling-point figure
Not yet cross-checked against a primary source. The value is provisional, used to place the compound on the volatility axis. Why this detail matters