Argon-39
A trace radioisotope of argon with atomic mass of 38.964313 and a half-life of 269 years. — ChEBI
Safety documents & references
Supplier matching mattersFind the safety document for your specific supplier, product number and grade.
Find a product-specific SDS
Safety guides and government classification records are not a manufacturer’s SDS. Match supplier, product number, concentration, physical form, region and revision before using a document.
Identity & molecular properties
Source-linked values| CAS number | 25729-41-3 | ChEBI ↗ |
| Molecular formula | [39Ar] | ChEBI ↗ |
| Molar mass | 38.964 g/mol | ChEBI ↗ |
| Monoisotopic mass | 38.96431 Da | ChEBI ↗ |
| Formal charge | 0 | ChEBI ↗ |
| ChEBI identifier | CHEBI:155827 | ChEBI ↗ |
Cross-source molecular data
PubChem| Molar mass | 38.96431 g/mol | PubChem ↗ |
| Exact mass | 38.96431 Da | PubChem ↗ |
PubChem computed values are shown separately from the ChEBI record. An exact InChIKey match was used to connect the records. Molecular descriptors do not describe a supplied product’s purity, particle size or performance.
Names & structural identifiers
Copy any identifierargon-39 atomargon-39XKRFYHLGVUSROY-BJUDXGSMSA-N[39Ar]InChI=1S/Ar/i1-1Classification & relationships
ChEBI ontologyRoles recorded in ChEBI
Database role annotations describe reported biological or chemical roles; they are not product approvals or recommendations for use.
Mass ↔ amount of substance
Calculated from sourced massUses 38.964 g/mol from ChEBI. Assumes the substance described by this record; no purity or concentration correction is applied.
Research & patent references
Selected source associationsSources & record history
Checked 27 Sep 2026Release 255, 9 September 2026. ChEBI three-star (manually annotated) source entry. View original record ↗ · CC BY 4.0
PubCAS formats source data, connects references and computes explicitly labelled conversions. CAS cross-references are supplied by ChEBI; they do not constitute CAS verification or endorsement.