Citronellal
Citronellal or rhodinal or 3,7-dimethyloct-6-en-1-al (C10H18O) is a monoterpenoid, the main component in the mixture of terpenoid chemical compounds that give citronella oil its distinctive lemon scent.
Citronellal is a major isolate in distilled oils from the plants Cymbopogon, lemon-scented gum, and lemon-scented teatree. The (–)-(S)-enantiomer of citronellal makes up up to 80% of the leaf oil from kaffir lime leaves and is the compound responsible for its characteristic aroma.