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1,2,3-triazole numbering.png
IUPAC name
Other names
3D model (JSmol)
ECHA InfoCard 100.128.405
Molar mass 69.0654
Appearance colorless liquid
Density 1.192
Melting point 23 to 25 °C (73 to 77 °F; 296 to 298 K)
Boiling point 203 °C (397 °F; 476 K)
very soluble
Acidity (pKa) 1.2
Basicity (pKb) 9.4
Related compounds
Related compounds
1,2,4-triazole imidazole
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

1,2,3-Triazole is one of a pair of isomeric chemical compounds with molecular formula C2H3N3, called triazoles, which have a five-membered ring of two carbon atoms and three nitrogen atoms. 1,2,3-Triazole is a basic aromatic heterocycle.[1]

Substituted 1,2,3-triazoles can be produced using the azide alkyne Huisgen cycloaddition in which an azide and an alkyne undergo a 1,3-dipolar cycloaddition reaction.

It is a surprisingly stable structure compared to other organic compounds with three adjacent nitrogen atoms. However, flash vacuum pyrolysis at 500 °C leads to loss of molecular nitrogen (N2) leaving a three-member aziridine ring. Certain triazoles are relatively easy to cleave due to ring-chain tautomerism. One manifestation is found in the Dimroth rearrangement.

1,2,3-Triazole finds use in research as a bioisostere in medicinal chemistry[2] building block for more complex chemical compounds, including pharmaceutical drugs such as mubritinib and tazobactam.


  1. ^ Heterocyclic chemistry T.L. Gilchrist ISBN 0-582-01421-2
  2. ^ Bonandi, E.; Christodoulou, M. S.; Fumagalli, G.; Perdicchia, D.; Rastelli, G.; Passarella, D. (2017). "The 1,2,3-triazole ring as a bioisostere in medicinal chemistry". Drug Discov Today: 1572–1581. doi:10.1016/j.drudis.2017.05.014.