1,2,3-Triazole (C2H3N3): structure, properties and hazards

Names and identifiers

IUPAC name: 2H-triazole
Synonyms: click chemistry product, osotriazole, 1H-1,2,3-Triazole
+ 35 more
2H-1,2,3-triazole, 1,2,3-1H-Triazole, 2H-triazole, Osotriazole, triazol, 1,2,3-triazol, V-triazole, MFCD00014490, Triazacyclopentadiene, racemic triazole, 1H-1,2,3-triazol, 2,3-Diazapyrrole, 1,2,3 triazole, 1H-[1,2,3]triazole, 2H-(1,2,3)-triazole, 1-H-1, 2, 3-triazole, 1~{H}-1,2,3-triazole, CHEBI:35565, DTXSID30870495, BCP18903, EM7554254W, AB01140, A25412, 1H-(1,2,3)-triazole, 1H-[1,2,3]-triazole, A8189, [1,2,3]triazole, Triazoles, HUH, MFCD00962232, 1h1,2,3-triazole, 1H-1,2,3 triazole, SCHEMBL102, 1-H-1,2,3-triazole, 2H-[1,2,3]triazole
Molecular formula: C₂H₃N₃
Empirical formula: C₂H₃N₃
Molecular weight: 69.07 g/mol
Exact mass: 69.03270
CAS number: 288-36-8
PubChem CID: 67516
Canonical SMILES: C1=NNN=C1
Isomeric SMILES: C1=NNN=C1
InChI: InChI=1S/C2H3N3/c1-2-4-5-3-1/h1-2H,(H,3,4,5)
InChIKey: QWENRTYMTSOGBR-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Calculated

Heavy atoms: 5
Rings: 1
Aromatic rings: 1
Fraction sp³ carbons (Fsp3): 0
H-bond donors: 1
H-bond acceptors: 2
Rotatable bonds: 0
TPSA (Å²): 41.6
Formal charge: 0
XLogP3: -0.3 PubChem
Complexity: 24 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C2v of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C34.78%
H4.38%
N60.84%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: -0.2 Crippen (Wildman and Crippen 1999)
log S (water solubility): -0.89 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 3.73 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 69.07
log P ≤ 5 (Crippen): -0.2
H-bond donors ≤ 5: 1
H-bond acceptors ≤ 10: 2

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Warning

Most widely reported: 91 company reports to ECHA. Source [1].

Harmful or irritant

H315Causes skin irritation
H319Causes serious eye irritation
H335May cause respiratory irritation (96.7% of reports)

Precautionary statements: P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501

Safety data sheets on the supplier’s page: Debye Scientific Co., Ltd, RR Scientific, Alfa Chemistry.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[2]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[3]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[4]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[5]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[6]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
[7]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.

Isomers in the library

1,2,4-Triazole