Water
An oxygen hydride consisting of an oxygen atom that is covalently bonded to two hydrogen atoms — ChEBI
Quick answers about Water
Identity · formula · massWhat is Water, CAS 7732-18-5?
Water is the substance linked to CAS 7732-18-5 in ChEBI entry CHEBI:15377. The reported formula is H2O. Confirm the structural identifiers when distinguishing salts, hydrates, isomers or isotopically labelled materials.
Source ↗What is the molar mass of Water?
The ChEBI-reported molar mass is 18.015 g/mol for formula H2O. Its source-reported monoisotopic mass is 18.01056 Da; that uses a specific isotope composition and is a different quantity.
Source ↗Which PubChem properties are available for Water?
CID 962 is connected to this record by an exact InChIKey match. PubChem reports exact mass 18.010564683 Da. Values and source conventions are shown separately in the property tables below.
Source ↗Identity & molecular properties
Source-linked values| CAS number | 7732-18-5 | ChEBI ↗ |
| Chemical formula | H2O | ChEBI ↗ |
| Molar mass | 18.015 g/mol | ChEBI ↗ |
| Monoisotopic mass | 18.01056 Da | ChEBI ↗ |
| Formal charge | 0 | ChEBI ↗ |
| ChEBI identifier | CHEBI:15377 | ChEBI ↗ |
PubChem molecular properties
PubChem| Molar mass | 18.015 g/mol | PubChem ↗ |
| Exact mass | 18.010564683 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 identifierwateroxidaneXLYOFNOQVPJJNP-UHFFFAOYSA-N[H]O[H]InChI=1S/H2O/h1H2Names & synonyms
Names are supplied by ChEBI. Trade names and related synonyms may describe a broader product context.
Classification & relationships
ChEBI ontologyRoles recorded in ChEBI
Database role annotations describe reported biological or chemical roles; they are not product approvals or recommendations for use.
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.
Mass ↔ amount of substance
Calculated from sourced massUses 18.015 g/mol from ChEBI; basis: the substance and formula represented in this record. No purity or concentration correction is applied.
Elemental composition
Theoretical mass fractionsOHCalculated theoretical mass fractions from the reported formula and PubChem periodic-table atomic masses. These are not assay or purity results.
Research & patent references
Selected source associationsExplore literature using this exact identifier.
Sources & 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.