trans-2-Decenal

Say itTRANZ-TOO-DES-uh-nal

Fatty-waxy aldehyde that turns to orange zest and fresh cilantro when diluted.

What it is: A molecule made in a lab.
When you smell it: Top notes: the first minutes.
What perfumers do with it: Offsets harsh decanal in aldehydic florals; adds realistic citrus-peel texture in tiny doses.
Worth knowing: Neat, it smells startlingly like chicken fat; at parts per million it reads as orange zest.
Also called: (E)-dec-2-enal

Not on the label of any of the 232 perfumes read so far.

Sources