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Chemical substance record

Water

7732-18-5H2O18.015 g/mol

An oxygen hydride consisting of an oxygen atom that is covalently bonded to two hydrogen atoms — ChEBI

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Identity & molecular properties

Source-linked values
CAS number7732-18-5ChEBI ↗
Molecular formulaH2OChEBI ↗
Molar mass18.015 g/molChEBI ↗
Monoisotopic mass18.01056 DaChEBI ↗
Formal charge0ChEBI ↗
ChEBI identifierCHEBI:15377ChEBI ↗

Cross-source molecular data

PubChem
Molar mass18.015 g/molPubChem ↗
Exact mass18.010564683 DaPubChem ↗

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 identifier
water
oxidane
XLYOFNOQVPJJNP-UHFFFAOYSA-N
[H]O[H]
InChI=1S/H2O/h1H2

Names & synonyms

oxidane

Names are supplied by ChEBI. Trade names and related synonyms may describe a broader product context.

Classification & relationships

ChEBI ontology

Roles recorded in ChEBI

amphiprotic solventmouse metaboliteSaccharomyces cerevisiae metabolitegreenhouse gasEscherichia coli metabolitehuman metabolite

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 mass
Equivalent amount
0.0555093 mol

Uses 18.015 g/mol from ChEBI. Assumes the substance described by this record; no purity or concentration correction is applied.

Elemental composition

Theoretical mass fractions
O
Oxygen · 1 atom
88.81%
H
Hydrogen · 2 atoms
11.19%

Calculated theoretical mass fractions from the reported formula and PubChem periodic-table atomic masses. These are not assay or purity results.

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Sources & record history

Checked 27 Sep 2026
EMBL-EBI ChEBI · CHEBI:15377

Release 255, 9 September 2026. ChEBI three-star (manually annotated) source entry. View original record ↗ · CC BY 4.0

NCBI PubChem · CID 962 · retrieved 2026-09-27

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.