Glossary · Molecule

Aldehyde C-9

Aldehyde C-9 (IUPAC: nonanal; CAS 124-19-6) is a synthetic aliphatic aldehyde with a fatty, waxy, and slightly green character, used in fine fragrance to add naturalness and diffusion to floral and chypre compositions (Perfumer & Flavorist, accessed 2026-05-27).

Technical detail

At nine carbons, Aldehyde C-9 occupies the lighter end of the classic aliphatic aldehyde range. Its olfactive profile combines a green, grassy, slightly rose-like quality with the characteristic waxy fatty facet of the series. It occurs naturally in trace amounts in many citrus and floral essential oils, giving its use in perfumery a naturalistic effect even when synthetically sourced (IFRA ingredient data, accessed 2026-05-27).

Compared to C-10 and C-12, C-9 is used less frequently in canonical aldehydic florals but appears more often in chypre and green floral structures where its lighter, more herbaceous quality adds freshness. It is also found as a trace contributor in rose absolute reconstructions (Basenotes molecule guide, accessed 2026-05-27).

Examples

  • Green floral chypres: Aldehyde C-9 contributes green naturalness to the fresh top layers.
  • Rose reconstructions: trace C-9 adds a naturalistic waxy-green facet to synthetic rose accords.
  • Often found alongside C-10, C-11, C-12 in the classic aldehyde palette of pre-1940 French perfumery compositions.

Sources

Published 2026-05-27 · Updated 2026-05-27 · Last fact check: 2026-05-27 · Osmetheca