Skip to content
[P]pubcas
Independent chemical reference Compare
Chemical substance record

Dihydrogen

1333-74-0H22.016 g/mol
ElementChEBI source record

An elemental molecule consisting of two hydrogens joined by a single bond. — ChEBI

Safety references

Safety documents & references

1 indexed references
JP · NITE

Government GHS classification

H30-C-085-MHLW · FY2018

View classification

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 number1333-74-0ChEBI ↗
Molecular formulaH2ChEBI ↗
Molar mass2.016 g/molChEBI ↗
Monoisotopic mass2.01565 DaChEBI ↗
Formal charge0ChEBI ↗
ChEBI identifierCHEBI:18276ChEBI ↗

Cross-source molecular data

PubChem
Molar mass2.016 g/molPubChem ↗
Exact mass2.0156500638 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
dihydrogen
dihydrogen
UFHFLCQGNIYNRP-UHFFFAOYSA-N
[H][H]
InChI=1S/H2/h1H

Classification & relationships

ChEBI ontology

Roles recorded in ChEBI

electron donorantioxidantfuelhuman metabolitefood packaging gas

Database role annotations describe reported biological or chemical roles; they are not product approvals or recommendations for use.

Safety classification · Japan

NITE / Japanese government
Japan · FY2018 source classification
Hydrogen · H30-C-085-MHLW
EndpointReported classification
Flammable gases (including chemically unstable gases)Category 1

Selected source-reported endpoints. Other endpoints, rationales and conditions remain in the original classification. Missing or unlisted information does not mean non-hazardous. This is not a global classification or transport decision.

Read the original NITE classification

Mass ↔ amount of substance

Calculated from sourced mass
Equivalent amount
0.496032 mol

Uses 2.016 g/mol from ChEBI. Assumes the substance described by this record; no purity or concentration correction is applied.

Elemental composition

Theoretical mass fractions
H
Hydrogen · 2 atoms
100.00%

Calculated 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 associations
Hydrogen-based, hollow-fiber membrane biofilm reactor for reduction of perchlorate and other oxidized contaminants. ↗Water science and technology : a journal of the International Association on Water Pollution Research · 2004 · PMID 15303745

Sources & record history

Checked 27 Sep 2026
EMBL-EBI ChEBI · CHEBI:18276

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

NCBI PubChem · CID 783 · 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.