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Structural formula
Structural formula of nitrotriazolone
Surname Nitrotriazolone
other names
  • NTO
  • 3-nitro-1,2,4-triazol-5-one
  • 5-nitro-2,4-dihydro-3 H -1,2,4-triazol-3-one
  • Oxynitrotriazole (ONTA)
Molecular formula C 2 H 2 N 4 O 3
External identifiers / databases
CAS number 932-64-9
EC number 213-254-4
ECHA InfoCard 100.012.050
PubChem 3453883
Wikidata Q906444
Molar mass 130.06 g mol −1
Physical state



1.91 g cm −3

Melting point

190–250 ° C (decomposition)


little in water (12.8 g l −1 at 19 ° C)

Refractive index


safety instructions
GHS labeling of hazardous substances
01 - Explosive 07 - Warning


H and P phrases H: 201-315-319-335
P: 210-280
Toxicological data

> 5000 mg kg −1 ( LD 50ratoral )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Nitrotriazolone ( NTO for short ) is an energetic, heterocyclic compound that is used as a component in many modern security explosives . The addition of nitrotriazolone can significantly reduce the sensitivity of explosives without compromising performance. Nitrotriazolone can be manufactured inexpensively in two steps.


NTO was first manufactured in 1905 by Wilhelm Manchot and R. Noll.

Extraction and presentation

NTO can be achieved by nitration of 1,2,4-triazole-5-one (TO) in 65% nitric acid produced at 65-70 ° C. Recrystallization from water with surfactants gives the suitable round grain shape.


NTO forms colorless crystals that are soluble in water , ethanol , methanol and acetic acid. It is sparingly soluble in acetone and ethyl acetate . It does not dissolve in non-polar solvents such as ether , chloroform and benzene . The compound can be recrystallized from dimethyl sulfoxide or methylene chloride .

NTO occurs in two polymorphic forms, the α-form being stable and the β-form can only be obtained by recrystallization.

NTO is a monobasic weak acid . It forms with silver - ion a light yellow silver salt which evaporates when heated. The value for the enthalpy of formation is ΔH f = −996 kJ / kg; So NTO is an exothermic compound. The detonation speed at maximum density is around 8600 m / s. With a density of 1.91 g / cm 3 , it has a detonation speed of 8200 m / s to 8400 m / s and a detonation pressure of 294 kbar.


NTO produces mixtures that can be poured with TNT , which are significantly less sensitive than comparable RDX- TNT mixtures. In a mixture with a thermoplastic binder, NTO is used in pressed charges for insensitive ammunition. With NTO, castable explosives with favorable safety properties and good performance values ​​can be produced.

NTO is used as a component of the explosive mixes IMX-101 and IMX-104, for example in the American 155 mm grenades of the type M795 .

Legal provisions

The manufacture and processing of NTO is prohibited in Germany without a permit under the Explosives Act.

Individual evidence

  1. a b c d Entry on 1,2-dihydro-5-nitro-3H-1,2,4-triazol-3-one in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
  2. ^ Carl L. Yaws: The Yaws Handbook of Physical Properties for Hydrocarbons and Chemicals . Gulf Professional Publishing, 2015, ISBN 978-0-12-801146-1 , pp. 13 ( limited preview in Google Book search).
  3. Safety data sheet 2,4-dihydro-5-nitro-3H-1,2,4-triazol-3-one from Apollo Scientific, accessed on March 1, 2015 (PDF).
  4. NTO , accessed March 1, 2015.
  5. W. Manchot, R. Noll: Ueber Derivate des Triazol. In: Justus Liebig's Annals of Chemistry. 343, 1905, pp. 1-27, doi: 10.1002 / jlac.19053430102 .
  6. Registration dossier on 1,2-dihydro-5-nitro-3H-1,2,4-triazol-3-one at the European Chemicals Agency (ECHA), accessed on March 1, 2015.
  7. Jai Prakash Agrawal: High Energy Materials: Propellants, Explosives and Pyrotechnics . John Wiley & Sons, 2010, ISBN 978-3-527-32610-5 , pp. 112 ( limited preview in Google Book search).
  8. a b Chemring Nobel: NTO , accessed on March 1, 2015.
  9. eurenco: EXE fiches eurenco NTO , accessed on March 1, 2015.
  10. Timothy E. Dawag, Dr. Jacob Morris: Nitrotriazolone Process Optimization ( Memento February 15, 2017 in the Internet Archive ). U.S. Army Research, Development and Engineering Command, May 15, 2012, accessed March 1, 2015.