Azelaic Acid Structure, Formula and Molecular Identity (CAS 123-99-9)
Azelaic Acid is the nine-carbon alpha,omega-dicarboxylic acid identified by CAS 123-99-9. Its IUPAC name is nonanedioic acid, its molecular formula is C9H16O4, and its molecular weight is 188.2209 g/mol. For unambiguous material matching, use the CAS together with the structural formula, InChIKey or SMILES—not the formula alone.
Azelaic Acid identity at a glance
| Common name | Azelaic Acid |
|---|---|
| IUPAC name | Nonanedioic acid |
| CAS Registry Number | 123-99-9 |
| EC number | 204-669-1 |
| Fórmula molecular | C9H16O4 |
| Peso molecular | 188.2209 g/mol (NIST; commonly rounded to 188.22) |
| Condensed structural formula | HOOC-(CH2)7-COOH |
| InChIKey | BDJRBEYXGGNYIS-UHFFFAOYSA-N |
| Canonical SMILES | C(CCCC(=O)O)CCCC(=O)O |
| PubChem CID | 2266 |
Identity references: NIST Chemistry WebBook: Azelaic Acid, PubChem CID 2266 y ECHA substance information.
What does the Azelaic Acid structure show?
The condensed structure HOOC-(CH2)7-COOH has a carboxylic-acid group at each end of a seven-methylene chain. Counting both carboxyl carbons gives nine carbons in total, which is why the systematic name is nonanedioic acid.
The two terminal carboxylic-acid groups make Azelaic Acid an alpha,omega-dicarboxylic acid. The molecule has no double bond or aromatic ring. Its structure should not be confused with sebacic acid, suberic acid, oleic acid or a salt/ester derived from Azelaic Acid.
Molecular formula versus structural formula
| Identifier | What it tells you | What it cannot prove alone |
|---|---|---|
| C9H16O4 | Element counts in one neutral molecule | A formula is not always a unique substance identifier |
| HOOC-(CH2)7-COOH | Functional groups and their chain arrangement | Grade, purity, impurity profile or lot identity |
| CAS 123-99-9 | The intended registry record | That a shipment meets the buyer’s specification |
| InChIKey / SMILES | Machine-readable connectivity for structure checking | Manufacturing route, regulatory status or application suitability |
| Current specification and lot COA | Test limits, methods and applicable lot results | Buyer-process performance without qualification testing |
Azelaic Acid molecular weight
NIST reports a molecular weight of 188.2209 g/mol; 188.22 g/mol is the common rounded value. Calculations should use the precision required by the buyer’s method and should distinguish the neutral acid from salts, esters, solvates or mixtures.
Azelaic Acid melting point
NIST phase-change records report fusion temperatures of 379.7 and 380.0 K, approximately 106.6–106.9 °C. A literature melting point is useful for identity context, but it is not a Longchang release specification or a substitute for the current test method, acceptance range and applicable lot result.
Reference: NIST Azelaic Acid phase-change data.
Azelaic Acid solubility in water
PubChem’s compiled records include water solubility of 2.4 g/L at 20 °C and describe greater solubility in hot water and alcohol. Solubility depends on temperature, solvent composition, particle characteristics, pH and the test method. Formulators should verify the exact conditions needed for their process instead of treating one reference value as a formulation guarantee.
How to verify CAS 123-99-9 before sourcing
- Match the name Azelaic Acid or nonanedioic acid with CAS 123-99-9.
- Confirm formula C9H16O4 and the two-terminal-carboxyl structure.
- Use InChIKey
BDJRBEYXGGNYIS-UHFFFAOYSA-Nor the SMILES when database matching matters. - Define assay method/basis, appearance, water, color, acid-value and impurity requirements in the RFQ.
- Review the current supplier specification, SDS status and applicable lot COA before accepting a shipment.
Regulatory and product-use boundaries
Azelaic Acid appears in specific finished topical-drug labels, but a finished product’s label, concentration and approval do not establish pharmaceutical grade or an approved use for a raw-material offer. For example, the DailyMed Azelex label applies to that named 20% cream and its documented formulation.
Azelaic Acid is also not food additive E900. The consolidated EU food-additives regulation identifies E 900 as dimethyl polysiloxane. Do not infer food-additive, GRAS, pharmaceutical, cosmetic or other regulated-grade suitability from the CAS identity page.
From molecular identity to application qualification
Once the identity is confirmed, use the Azelaic Acid properties and industrial sourcing guide to define application-screening questions, specification fields and an RFQ.
Review the Azelaic Acid CAS 123-99-9 sourcing page or email info@longchangchemical.com with the intended use, required tests, quantity, destination and document needs.
Frequently asked questions
What is the chemical formula of Azelaic Acid?
The molecular formula is C9H16O4.
What is the structural formula of Azelaic Acid?
The condensed structural formula is HOOC-(CH2)7-COOH, with one carboxylic-acid group at each end of the chain.
What is the IUPAC name of Azelaic Acid?
The IUPAC name is nonanedioic acid.
What is the molecular weight of Azelaic Acid?
NIST reports 188.2209 g/mol, commonly rounded to 188.22 g/mol.
Is Azelaic Acid the same as E900?
No. EU food-additives legislation identifies E 900 as dimethyl polysiloxane, not Azelaic Acid.
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