The Science · Chapter 2 of 5
The Molecules
Every fragrance is chemistry: the molecule constellation, the molecular explorer in three dimensions, GC-MS decoded and olfactory thresholds.
About 7 minutes of reading
The Molecule Constellation
Every scent family is built from particular molecules. Choose a molecule to see it turned in three dimensions, engraved like every plate in the house - and the family it belongs to.
Floral
Wood
Amber
Aldehyde
Marine
Musk
Citrus
Hedione
Geometry: PubChem CID 102861, a computed 3D conformer - a model, drawn schematically; not an experimental structure.
1 sourced
Evidence for this section: 1 sourced
Sources cited here include: PubChem Compound Summary for CID 102861, Hedione
The Molecular Explorer
Every fragrance is chemistry. Explore the molecules that shape modern perfumery - their structures, their scent profiles, and the fragrances that made them famous. Turn any of them in 3D and fit it into a schematic receptor pocket.
No molecule of this family in the explorer yet
The greens are coming with the next plates.
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Methyl dihydrojasmonate (Hedione)
methyl 2-(3-oxo-2-pentylcyclopentyl)acetate
- Formula
- C13H22O3
- Molar mass
- 226.31 g/mol
- CAS
- 24851-98-7
- PubChem
- CID 102861
InChIKey KVWWIYGFBYDJQC-UHFFFAOYSA-N · the record · the data
Radiant jasmine, airy and fresh, with a wide diffusion that seems to lift a fragrance off the skin. Light, transparent, dewy.
Discovery & significance
Developed at Firmenich and made famous by Edmond Roudnitska's Eau Sauvage for Dior. Laboratory research has reported that it activates a human receptor of the VN1R family; what that means for how people perceive it is still an open question.
Known from Eau Sauvage · CK One · J’adore · Acqua di Giò · Light Blue
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Iso E Super
1-(2,3,8,8-tetramethyl-1,3,4,5,6,7-hexahydronaphthalen-2-yl)ethanone
- Formula
- C16H26O
- Molar mass
- 234.38 g/mol
- CAS
- 54464-57-2
- PubChem
- CID 108242
InChIKey FVUGZKDGWGKCFE-UHFFFAOYSA-N · the record · the data
Velvety cedarwood, smooth and skin-like; an intimate, diffusive woody note that some people barely notice at all.
Discovery & significance
First made in the early 1970s by the chemist John B. Hall. Some people perceive it only faintly or not at all - see the Ghost Molecule below. Geza Schoen built Molecule 01 around it as a single-ingredient fragrance.
Known from Molecule 01 · Terre d’Hermès · Fahrenheit · Encre Noire · Jubilation XXV
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Ambroxan
(3aR,5aS,9aS,9bR)-3a,6,6,9a-tetramethyl-2,4,5,5a,7,8,9,9b-octahydro-1H-benzo[e][1]benzofuran
- Formula
- C16H28O
- Molar mass
- 236.39 g/mol
- CAS
- 6790-58-5
- PubChem
- CID 10857465
Warm, salty, mineral, skin-like - the air of skin after a day by the sea. Clean yet faintly animalic; perfumery's stand-in for ambergris.
Discovery & significance
Made from sclareol, a natural product of clary sage, or by full synthesis. Prized for its radiant skin-scent effect; it sits at the center of several widely worn masculine fragrances.
Known from Sauvage · Bleu de Chanel · Molecule 02 · Baccarat Rouge 540 · Not a Perfume
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Aldehyde C-11
undecanal
- Formula
- C11H22O
- Molar mass
- 170.29 g/mol
- CAS
- 112-44-7
- PubChem
- CID 8186
Fresh, clean, citrus-aldehydic with waxy, soapy undertones - the 'clean linen' note. Lends lift and diffusion to florals.
Discovery & significance
One of the fatty aldehydes (C-9 to C-12) that give the aldehydic florals their sparkle; Chanel No. 5 made the family famous.
Known from Chanel No. 5 · Arpège · White Linen · Calèche
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Calone
7-methyl-1,5-benzodioxepin-3-one
- Formula
- C10H10O3
- Molar mass
- 178.18 g/mol
- CAS
- 28940-11-6
- PubChem
- CID 120101
Sea breeze, watermelon rind, ozone - a marine freshness that smells like nothing in nature. The sea, reimagined in a bottle.
Discovery & significance
Made in a pharmaceutical laboratory in the 1960s and taken up by perfumery much later; the marine fragrances of the early 1990s, L'Eau d'Issey among them, turned it into a whole genre.
Known from L’Eau d’Issey · Cool Water · Escape · Acqua di Giò · CK One
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Galaxolide
4,6,6,7,8,8-hexamethyl-1,3,4,7-tetrahydrocyclopenta[g]isochromene
- Formula
- C18H26O
- Molar mass
- 258.40 g/mol
- CAS
- 1222-05-5
- PubChem
- CID 91497
Clean white musk - powdery, sweet, laundry-fresh. The archetype of 'clean', soft and long-lasting.
Discovery & significance
A polycyclic musk from IFF, as common in laundry products as in fine fragrance. Its persistence in the environment is monitored and debated, and some houses now choose other musks.
Known from White Musk (TBS) · Clean Skin · Happy · Chance
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Coumarin
chromen-2-one
- Formula
- C9H6O2
- Molar mass
- 146.14 g/mol
- CAS
- 91-64-5
- PubChem
- CID 323
InChIKey ZYGHJZDHTFUPRJ-UHFFFAOYSA-N · the record · the data
New-mown hay, tonka bean, sweet tobacco and almond - warm and balsamic, close to vanilla.
Discovery & significance
An early aroma molecule made in a laboratory, by Perkin in 1868. Houbigant's Fougère Royale used it and gave its name to a whole family, the fougères.
Known from Fougère Royale · Jicky · Drakkar Noir · Cool Water · Shalimar
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Linalool
3,7-dimethylocta-1,6-dien-3-ol
- Formula
- C10H18O
- Molar mass
- 154.25 g/mol
- CAS
- 78-70-6
- PubChem
- CID 6549
InChIKey CDOSHBSSFJOMGT-UHFFFAOYSA-N · the record · the data
Fresh lavender, clean floral, with citrus and wood undertones. Light, lifting, easy to love - the backbone of countless florals.
Discovery & significance
Found in many plants, lavender, coriander and rosewood among them, and a terpene alcohol widely used in perfumery. Its two mirror-image forms smell different: one woodier and more lavender-like, the other more floral.
Known from Pour Un Homme · Cool Water · Chanel No. 5 · Most florals
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Vanillin
4-hydroxy-3-methoxybenzaldehyde
- Formula
- C8H8O3
- Molar mass
- 152.15 g/mol
- CAS
- 121-33-5
- PubChem
- CID 1183
InChIKey MWOOGOJBHIARFG-UHFFFAOYSA-N · the record · the data
Sweet, warm vanilla - creamy and comforting. The molecule most responsible for vanilla's familiar scent.
Discovery & significance
Made in a laboratory from 1874, when Tiemann and Haarmann patented a synthesis from coniferin. Synthetic vanillin costs a small fraction of natural vanilla extract, which is what made gourmand perfumery affordable; it appears in a great many modern fragrances.
Known from Shalimar · Angel · Tobacco Vanille · Black Opium · Hypnotic Poison
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Cashmeran
1,1,2,3,3-pentamethyl-2,5,6,7-tetrahydroinden-4-one
- Formula
- C14H22O
- Molar mass
- 206.32 g/mol
- CAS
- 33704-61-9
- PubChem
- CID 92292
Woody-musky, soft and velvety, with spicy-amber undertones - warm, enveloping, like cashmere. A good fixative.
Discovery & significance
Created at IFF and named for its cashmere-like softness. It gives the velvet texture to many modern woody fragrances, working as both a heart note and a fixative.
Known from Dolce & Gabbana · Invictus · Gucci Guilty · Narciso Rodriguez
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Indole
1H-indole
- Formula
- C8H7N
- Molar mass
- 117.15 g/mol
- CAS
- 120-72-9
- PubChem
- CID 798
InChIKey SIKJAQJRHWYJAI-UHFFFAOYSA-N · the record · the data
At trace levels heady, narcotic, jasmine-like; at high concentration fecal and animalic. The same molecule reads as flower or decay depending on the dose.
Discovery & significance
Found naturally in jasmine, orange blossom and tuberose - and in decay. At the trace levels present in white flowers it gives narcotic depth without the fecal side.
Known from Chanel No. 5 · Joy · Carnal Flower · À la Nuit · Fracas
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Limonene
1-methyl-4-prop-1-en-2-ylcyclohexene
- Formula
- C10H16
- Molar mass
- 136.23 g/mol
- CAS
- 138-86-3
- PubChem
- CID 22311
InChIKey XMGQYMWWDOXHJM-UHFFFAOYSA-N · the record · the data
Fresh citrus, orange peel, zesty, clean and bright, and widely recognized.
Discovery & significance
The main terpene of citrus peel oils. Its two mirror-image forms have different scents - a small demonstration of how a molecule's handedness changes its smell.
Known from Eau de Cologne · Acqua di Parma · CK One · Light Blue · Most colognes
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β-Damascenone
(E)-1-(2,6,6-trimethylcyclohexa-1,3-dien-1-yl)but-2-en-1-one
- Formula
- C13H18O
- Molar mass
- 190.28 g/mol
- CAS
- 23696-85-7
- PubChem
- CID 5366074
InChIKey POIARNZEYGURDG-FNORWQNLSA-N · the record · the data
Rose, apple, dried fruit and honey - rich and complex; detected at 0.006 µg/kg in water.
Discovery & significance
A key contributor to the character of rose, and essential to rose reconstructions; also found in wine, tea and tobacco.
Known from Portrait of a Lady · Joy · Nahéma · Rose 31 · Sa Majesté la Rose
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Ethyl Maltol
2-ethyl-3-hydroxypyran-4-one
- Formula
- C7H8O3
- Molar mass
- 140.14 g/mol
- CAS
- 4940-11-8
- PubChem
- CID 21059
Cotton candy, burnt sugar and caramel - an intense sweetness, stronger than maltol's.
Discovery & significance
Its use at an unusually high dose in Mugler's Angel is widely credited with opening the gourmand family. The burnt-sugar sweetness was divisive and hugely influential.
Known from Angel · La Vie Est Belle · Black Opium · Good Girl · Cloud
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Javanol
- Formula
- C₁₅H₂₆O US EPA CompTox, DTXSID8051837
- CAS
- 198404-98-7
Creamy sandalwood - rich, warm, milky-sweet.
Discovery & significance
Developed by Givaudan as a sandalwood substitute at a time when sandalwood from Mysore had become scarce and protected. It is now central to modern creamy-woody fragrances.
Known from Le Labo Santal 33 · Tam Dao · Modern sandalwoods
No 3D model: PubChem has no record of this molecule
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Muscenone
3-methylcyclopentadec-5-en-1-one
- Formula
- C16H28O
- Molar mass
- 236.39 g/mol
- CAS
- 63314-79-4
- PubChem
- CID 54116156
An elegant macrocyclic musk - clean, animalic-powdery and long-lasting, close to the character of natural muscone.
Discovery & significance
A Firmenich macrocyclic musk. Macrocyclic musks are often described as natural-smelling, close to the animal note.
Known from Narciso Rodriguez · Le Labo Another 13 · Fine niche brands
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α-Isomethyl Ionone
(E)-3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one
- Formula
- C14H22O
- Molar mass
- 206.32 g/mol
- CAS
- 127-51-5
- PubChem
- CID 5372174
Powdery violet and iris - soft and romantic, with woody undertones.
Discovery & significance
One of the ionones, first made in the late nineteenth century. Violet flowers give almost no extractable oil, so the ionones made violet perfumery possible, and their powdery character marked decades of feminine fragrance.
Known from Après l’Ondée · Insolence · Ultraviolet · Fahrenheit
identity (formula, molar mass, IUPAC name, CID): PubChem (NCBI); the 3D models are PubChem’s computed conformers, drawn schematically. Scent descriptions are the house’s own.
Play and learn Which molecule does a source say smells of vanilla, hay or violets? Pair them in Molecule Match.
18 sourced
Evidence for this section: 18 sourced
Sources cited here include: PubChem Compound Summary for CID 102861, Hedione; PubChem Compound Summary for CID 108242, 1-(1,2,3,4,5,6,7,8-Octahydro-2,3,8,8-tetramethyl-2-naphthalenyl)ethanone; PubChem Compound Summary for CID 10857465, (-)-Ambroxide. National Center for Biotechnology Information
The GC-MS Decoder
Every fragrance formula is a trade secret. But gas chromatography–mass spectrometry can separate a mixture into its components and identify most of them, and houses routinely analyze each other’s launches. Here’s what it reveals — and what it can’t.
An illustrative chromatogram of rose
Illustrative, modeled: the compounds are documented rose constituents; the retention times and peak heights are invented for this picture and its sound.
Sound is off. Each peak becomes a note: when it leaves the column sets when you hear it, its height sets how loud, its chemical family sets the instrument.
The peaks, in order
- The list of peaks appears here with the script.
A gas chromatograph separates a mixture by boiling point — each component exits the column at a different time. The mass spectrometer fragments each molecule and measures the fragments. The result is a chromatogram: each peak a compound, identified from its mass spectrum, with a rough idea of how much of it there is.
A trained analyst can read much of a commercial fragrance this way. The large houses run their own instruments; independent perfumers can use university facilities or commercial analytical labs.
Lists of “what GC-MS found” in famous fragrances — this molecule at this percentage — travel widely, usually without the study behind them. The house prints none of them until each can be traced to a published analysis.
2 labeled · 3 unsourced
Evidence for this section: 2 labeled · 3 unsourced
Olfactory Thresholds
The concentration at which a molecule first becomes perceptible differs enormously from one odorant to the next. Understanding it is part of formula design: it tells you how much of each material you actually need.
A detection threshold is usually defined as the lowest concentration that half of a test panel can perceive, measured in air or in water. The lower the number, the more powerful the odorant.
| Molecule | Odor character | Why it matters | Detection threshold, with its medium |
|---|---|---|---|
| β-Damascenone | Rose, fruity, tobacco | Detected at a few parts per trillion: a trace changes a whole accord | 0.006 µg/kg in water |
| Indole | Floral or fecal, by concentration | Present in jasmine; its double nature makes it both essential and risky | 11 µg/kg in water |
| Ethyl mercaptan | Sulfurous, onion | Added to natural gas so leaks can be smelled; the same power in a trace is what perfumers call “skank” | 0.0000087 ppm (v/v) in air |
| Iso E Super | Woody, cedar, transparent | A modern synthetic often used generously; some people perceive it only faintly or not at all | — |
| Ambroxan | Ambergris, skin-warm | Works at low levels and diffuses, lifting the whole composition | — |
| Muscone | Diffusive musk | The reference character for natural musk | — |
| Linalool | Floral, lavender | Common but relatively weak; needs a real concentration to register | 3.2 ng/L in air; 0.58 µg/kg in water (the racemate) |
| Geraniol | Rose, geranium | Among the weaker major aroma chemicals; used in larger quantities | 1.1 µg/kg in water |
| Calone | Marine, watermelon | Strong at very low concentrations; the signature of the aquatic family | — |
| Coumarin | Hay, tonka, sweet | The backbone of the fougère: noticeable at moderate levels, comfortable at high ones | — |
| α-Ionone | Violet, orris-like | Violet reconstructions; known for fading from notice quickly as the nose adapts | — |
| Vanillin | Vanilla | Relatively weak, one reason oriental formulas use it in large amounts | 53 µg/kg in water |
the house’s own descriptions. The thresholds are read from the records: in water, the Leibniz-LSB@TUM Odorant Database (the method of Czerny et al. 2008); in air, Elsharif et al. 2015 (GC-olfactometry) for linalool and Nagata’s triangle odor bag method (Ministry of the Environment, Japan) for ethyl mercaptan. Values in water and in air are not comparable with each other. “Not on record”: published values for that molecule differ by orders of magnitude between methods and panels, and it will be printed once traced to its study.
3 unsourced
Evidence for this section: 3 unsourced
