Skeletal formula of acetonitrile
Skeletal formula of acetonitrile
Skeletal formula of acetonitrile with all explicit hydrogens added
Skeletal formula of acetonitrile with all explicit hydrogens added
Ball and stick model of acetonitrile
Ball and stick model of acetonitrile
Spacefill model of acetonitrile
Spacefill model of acetonitrile
Preferred IUPAC name
Systematic IUPAC name
Other names
  • Cyanomethane[1]
  • Ethyl nitrile[1]
  • Methanecarbonitrile[1]
  • Methyl cyanide[1]
  • MeCN
  • ACN
3D model (JSmol)
ECHA InfoCard 100.000.760 Edit this at Wikidata
EC Number
  • 200-835-2
MeSH acetonitrile
RTECS number
  • AL7700000
UN number 1648
  • InChI=1S/C2H3N/c1-2-3/h1H3 checkY
  • CC#N
Molar mass 41.053 g·mol−1
Appearance Colorless liquid
Odor Faint, distinct, fruity
Density 0.786 g/cm3 at 25°C
Melting point −46 to −44 °C; −51 to −47 °F; 227 to 229 K
Boiling point 81.3 to 82.1 °C; 178.2 to 179.7 °F; 354.4 to 355.2 K
log P −0.334
Vapor pressure 9.71 kPa (at 20.0 °C)
530 μmol/(Pa·kg)
Acidity (pKa) 25
UV-vismax) 195 nm
Absorbance ≤0.10
−28.0×10−6 cm3/mol
3.92 D
91.69 J/(K·mol)
149.62 J/(K·mol)
40.16–40.96 kJ/mol
−1256.03 – −1256.63 kJ/mol
GHS labelling:
GHS02: Flammable GHS07: Exclamation mark
H225, H302, H312, H319, H332
P210, P280, P305+P351+P338
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
Flash point 2.0 °C (35.6 °F; 275.1 K)
523.0 °C (973.4 °F; 796.1 K)
Explosive limits 4.4–16.0%
Lethal dose or concentration (LD, LC):
  • 2 g/kg (dermal, rabbit)
  • 2.46 g/kg (oral, rat)
5655 ppm (guinea pig, 4 hr)
2828 ppm (rabbit, 4 hr)
53,000 ppm (rat, 30 min)
7500 ppm (rat, 8 hr)
2693 ppm (mouse, 1 hr)[4]
16,000 ppm (dog, 4 hr)[4]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 40 ppm (70 mg/m3)[3]
REL (Recommended)
TWA 20 ppm (34 mg/m3)[3]
IDLH (Immediate danger)
500 ppm[3]
Related compounds
Related alkanenitriles
Related compounds
Supplementary data page
Acetonitrile (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Acetonitrile, often abbreviated MeCN (methyl cyanide), is the chemical compound with the formula CH3CN and structure H3C−C≡N. This colourless liquid is the simplest organic nitrile (hydrogen cyanide is a simpler nitrile, but the cyanide anion is not classed as organic). It is produced mainly as a byproduct of acrylonitrile manufacture. It is used as a polar aprotic solvent in organic synthesis and in the purification of butadiene.[5] The N≡C−C skeleton is linear with a short C≡N distance of 1.16 Å.[6]

Acetonitrile was first prepared in 1847 by the French chemist Jean-Baptiste Dumas.[7]

  1. ^ a b c d "Material Safety Data Sheet: Acetonitrile" (PDF).
  2. ^ a b Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 902. doi:10.1039/9781849733069-FP001 (inactive 2024-05-06). ISBN 978-0-85404-182-4.{{cite book}}: CS1 maint: DOI inactive as of May 2024 (link)
  3. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0006". National Institute for Occupational Safety and Health (NIOSH).
  4. ^ a b "Acetonitrile". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  5. ^ "Archived copy" (PDF). Ashford's Dictionary of Industrial Chemicals, Third edition. p. 76. Archived from the original (PDF) on 2011-05-16. Retrieved 2011-03-31.{{cite web}}: CS1 maint: archived copy as title (link)
  6. ^ Karakida, Ken'ichi; Fukuyama, Tsutomu; Kuchitsu, Kozo (1974). "Molecular Structures of Hydrogen Cyanide and Acetonitrile as Studied by Gas Electron Diffraction". Bulletin of the Chemical Society of Japan. 47 (2): 299–304. doi:10.1246/bcsj.47.299.
  7. ^ Dumas, J.-B. (1847). "Action de l'acide phosphorique anhydre sur les sels ammoniacaux" [Action of anhydrous phosphoric acid on ammonium salts]. Comptes rendus. 25: 383–384.