1,2,4-Triazole

Athanor · official

C₂H₃N₃ · 69.07 g/mol

IUPAC name: 1H-1,2,4-triazole

Also called pyrrodiazole

Rings

Open in Athanor

Drawn from its SMILES with RDKit

DangerHarmful if swallowed · Causes serious eye irritation · May damage fertility; May damage the unborn child

Names and identifiers

IUPAC name: 1H-1,2,4-triazole
Synonyms: pyrrodiazole, 1H-1,2,4-Triazole, Pyrrodiazole
+ 34 more
s-Triazole, DTXSID6027131, 10MS0Y1RDI, NSC-83128, DTXCID207131, CHEBI:35550, RefChem:908322, CHEBI:35560, 206-022-9, 4H-1,2,4-triazole, 1,2,4-1H-Triazole, MFCD00005228, 1H-1,2,4-triazol, 1,2,4 triazole, 1,2,4-triazol, C2H3N3, NSC 83128, 4H-1,4-Triazole, 1,2,4,-triazole, 1, 2, 4 triazole, 1H-[1,2,4]triazole, Triazole-[13C2,15N3], CHEBI:46077, 1H-1,2,4-TRIAZOLE [HSDB], (1,2,4)-triazole, [1,2,4]-triazole, T0340, E76126, 4H-1,2,4-Triazole (VAN), Fluconazole Impurity 20, EINECS 206-022-9, UNII-10MS0Y1RDI, AI3-51031, HSDB 7860
Molecular formula: C₂H₃N₃
Empirical formula: C₂H₃N₃
Molecular weight: 69.07 g/mol
Exact mass: 69.03270
CAS number: 288-88-0
PubChem CID: 9257
Canonical SMILES: C1=NC=NN1
Isomeric SMILES: C1=NC=NN1
InChI: InChI=1S/C2H3N3/c1-3-2-5-4-1/h1-2H,(H,3,4,5)
InChIKey: NSPMIYGKQJPBQR-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Other Solid; Large Crystals[1]
2 values
From EPA Chemical Data Reporting (CDR), the most authoritative source here.
Value As written Source
–shown Other Solid; Large Crystals [1] EPA Chemical Data Reporting (CDR)
– BROWN SOLID IN VARIOUS FORMS WITH CHARACTERISTIC ODOUR. [2] ILO-WHO International Chemical Safety Cards (ICSCs)
Melting point: 120-121 °C[2]
Boiling point: 260 °C[2]
Density: 640 kg/m³[2]
Solubility in water: Solubility in water, g/100ml at 20 °C: 125[2]
log P: -0.6[2]
2 values
Sources disagree; from ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative.
Value As written Source
– log Kow = -0.58 [3] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 4
–shown -0.6 [2] ILO-WHO International Chemical Safety Cards (ICSCs)
Vapor pressure: Vapor pressure, Pa at 20 °C: 0.2[2]
Flash point: 170 °C c.c.[2]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
170 °C 170 °C closed cup [3] Hazardous Substances Data Bank (HSDB)cites European Commission, ESIS; IUCLID Dataset, 1,2,4-Triazole (288-88-0) p.6 (2000 CD-ROM edition). Available from, as of September 23, 2010: https://esis.jrc.ec.europa.eu/
170 °Cshown 170 °C c.c. [2] ILO-WHO International Chemical Safety Cards (ICSCs)
Autoignition temperature: 490 °C[2]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
490 °C 490 °C [3] Hazardous Substances Data Bank (HSDB)cites International Program on Chemical Safety/Commission of the European Communities; International Chemical Safety Card on 1,2,4-Triazole (April 2007). Available from, as of September 23, 2010: https://www.inchem.org/pages/icsc.html
490 °Cshown 490 °C [2] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–shown	Other Solid; Large Crystals	[1] EPA Chemical Data Reporting (CDR)
–	BROWN SOLID IN VARIOUS FORMS WITH CHARACTERISTIC ODOUR.	[2] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	log Kow = -0.58	[3] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 4
–shown	-0.6	[2] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
170 °C	170 °C closed cup	[3] Hazardous Substances Data Bank (HSDB)cites European Commission, ESIS; IUCLID Dataset, 1,2,4-Triazole (288-88-0) p.6 (2000 CD-ROM edition). Available from, as of September 23, 2010: https://esis.jrc.ec.europa.eu/
170 °Cshown	170 °C c.c.	[2] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
490 °C	490 °C	[3] Hazardous Substances Data Bank (HSDB)cites International Program on Chemical Safety/Commission of the European Communities; International Chemical Safety Card on 1,2,4-Triazole (April 2007). Available from, as of September 23, 2010: https://www.inchem.org/pages/icsc.html
490 °Cshown	490 °C	[2] ILO-WHO International Chemical Safety Cards (ICSCs)

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

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: -0.6 PubChem
Complexity: 28 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: Cs 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: 4.1 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

Danger

Harmonized EU classification (CLP Annex VI). Source [4].

Harmful or irritant
Health hazard

H302Harmful if swallowed
H319Causes serious eye irritation
H360FDMay damage fertility; May damage the unborn child

Precautionary statements: P203, P264, P264+P265, P270, P280, P301+P317, P305+P351+P338, P318, P330, P337+P317, P405, P501

View all classifications (2)

[4] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH302, H319, H360FD
[5] European Chemicals Agency (ECHA) · 529 reports · DangerH302, H319, H360FD, H361, H361d, H412

First aid

Fresh air, rest.[2]
Remove contaminated clothes. Remove contaminated clothes. Rinse skin with plenty of water or shower.[2]
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.[2]
Rinse mouth. Give one or two glasses of water to drink. Refer for medical attention .[2]

Storage

Separated from strong oxidants and strong acids. Store in an area without drain or sewer access.[2]
Keep container tightly closed in a dry and well-ventilated place.[3]
Separated from strong oxidants, and strong acids. Store in an area without drain or sewer access.[3]

Incompatibilities

Reacts with strong acids and strong oxidants.[3]

Safety data sheets on the supplier’s page: Ambeed, Sigma-Aldrich, 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]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[2]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[3]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[4]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[5]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[6]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[7]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[8]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[9]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
[10]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.