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Acetonitrile

Athanor · official

C2H3N · 41.05 g/mol

Also called MeCN, ACN, methyl cyanide, cyanomethane

Open in Athanor
The structure of Acetonitrile
Drawn from its SMILES with RDKit320
FlammableHarmful or irritantDangerHighly Flammable liquid and vapor · Harmful if swallowed · Harmful in contact with skin · Causes serious eye irritation · Harmful if inhaled

Names and identifiers

IUPAC name
acetonitrile
Synonyms
MeCN, ACN, methyl cyanide
+ 37 more

cyanomethane, Methyl cyanide, Cyanomethane, Ethanenitrile, Ethyl nitrile, Methane, cyano-, Methanecarbonitrile, Acetonitril, Cyanure de methyl, Methylkyanid, USAF EK-488, RCRA waste number U003, NCI-C60822, DTXSID7020009, AI3-00327, Z072SB282N, NSC-7593, DTXCID909, CHEBI:38472, RefChem:6609, 200-835-2, Methylkyanid [Czech], Cyanure de methyl [French], Acetonitril [German, Dutch], Acetonitrile, anhydrous, CH3CN, Acetonitrile with 0.1% ammonium acetate, MFCD00001878, ACETONITRILE WITH 0.1per cent AMMONIUM ACETATE, anhydrous Acetonitrile, ACETONITRILE (2-13C, 99%), Acetonitrile [UN1648] [Flammable liquid], Methyl Cyanide, Cyanomethane, Ethanenitrile, ethyl, Acetonitril (GERMAN, DUTCH), Acetonitrile, for DNA synthesis, acetnitrile, Ethanonitrile

Molecular formula
C2H3N
Empirical formula
C2H3N
Molecular weight
41.05 g/mol
Exact mass
41.02655
CAS number
75-05-8
PubChem CID
6342
Canonical SMILES
CC#N
Isomeric SMILES
CC#N
InChI
InChI=1S/C2H3N/c1-2-3/h1H3
InChIKey
WEVYAHXRMPXWCK-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity
Appearance
Colorless, limpid liquid[6]
6 values

From Hazardous Substances Data Bank (HSDB), the most authoritative source here.

ValueAs writtenSource
–Acetonitrile appears as a colorless limpid liquid with an aromatic odor. Flash point 42 °F. Density 0.783 g / cm3. Toxic by skin absorption. Less dense than water. Vapors are denser than air.[1] CAMEO Chemicals
–CBI; Liquid[2] EPA Chemical Data Reporting (CDR)
–COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–Colorless liquid with an aromatic odor.[4] Occupational Safety and Health Administration (OSHA)
–Colorless liquid with an aromatic odor.[5] The National Institute for Occupational Safety and Health (NIOSH)
–shownColorless, limpid liquid[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 9
Odor
Aromatic odor[6]
2 values

From Hazardous Substances Data Bank (HSDB), the most authoritative source here.

ValueAs writtenSource
–shownAromatic odor[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
–Sweet, ethereal odor[6] Hazardous Substances Data Bank (HSDB)cites DeVito SC; Nitriles. Kirk-Othmer Encyclopedia of Chemical Technology. (1999-2014). New York, NY: John Wiley & Sons. Online Posting Date: Sept 14, 2007.
Melting point
-45 °C (-49 °F, NTP 1992)[1]
5 values

5 of 5 sources agree on it (most common value).

ValueAs writtenSource
−45 °Cshown-49 °F (NTP, 1992)[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−46 °C-46 °C[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−45 °C-49 °F[4] Occupational Safety and Health Administration (OSHA)
−43.8 °C-43.82 °C[7] PAC Chemical Database, U.S. Department of Energy
−45 °C-49 °F[5] The National Institute for Occupational Safety and Health (NIOSH)
Boiling point
81.65 °C @760 [mmHg][7]
5 values

5 of 5 sources agree on it (most common value).

ValueAs writtenSource
81.6 °C178.9 °F at 760 mmHg (NTP, 1992)[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
82 °C82 °C[3] ILO-WHO International Chemical Safety Cards (ICSCs)
82 °C179 °F[4] Occupational Safety and Health Administration (OSHA)
81.7 °Cshown81.65 °C @760 [mm Hg][7] PAC Chemical Database, U.S. Department of Energy
82 °C179 °F[5] The National Institute for Occupational Safety and Health (NIOSH)
Density
0.786 @ 20°C[7]
5 values

5 of 5 sources agree on it (most common value).

ValueAs writtenSource
–0.787 at 68 °F (USCG, 1999) - Less dense than water[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
–Relative density (water = 1): 0.8[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–0.787[4] Occupational Safety and Health Administration (OSHA)
–shown0.786 @ 20°C[7] PAC Chemical Database, U.S. Department of Energy
–0.78[5] The National Institute for Occupational Safety and Health (NIOSH)

6 more values were reported but failed the checks (unreadable or out of range), so they are not shown.

Solubility in water
Solubility in water, g/100ml at 20 °C: 1390 (very good)[3]
7 values

From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.

ValueAs writtenSource
–greater than or equal to 100 mg/mL at 72.5 °F (NTP, 1992)[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–In water, >800 g/L at 25 °C[6] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan, Jain, P. Handbook of Aqueous Solubility Data Second Edition. CRC Press, Boca Raton, FL 2010, p. 27
–In water, infinite solubility at 25 °C[6] Hazardous Substances Data Bank (HSDB)cites Riddick, J.A., W.B. Bunger, Sakano T.K. Techniques of Chemistry 4th ed., Volume II. Organic Solvents. New York, NY: John Wiley and Sons., 1985., p. 583
–Soluble in alcohol[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 9
–For more Solubility (Complete) data for ACETONITRILE (6 total), please visit the HSDB record page.[6] Hazardous Substances Data Bank (HSDB)
–shownSolubility in water, g/100ml at 20 °C: 1390 (very good)[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–Miscible[5] The National Institute for Occupational Safety and Health (NIOSH)
log P
-0.3[3]
2 values

Sources disagree; from ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative.

ValueAs writtenSource
–log Kow = -0.34[6] 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-0.3[3] ILO-WHO International Chemical Safety Cards (ICSCs)
pKa
pKa = -4.30 (conjugate acid)[6]
Vapor pressure
Vapor pressure, kPa at 25 °C: 9.9[3]
4 values

3 of 4 sources agree on it (most common value).

ValueAs writtenSource
73 mmHg73 mmHg at 68 °F (NTP, 1992)[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
88.8 mmHg88.8 mm Hg at 25 °C[6] Hazardous Substances Data Bank (HSDB)cites Boublik, T., Fried, V., and Hala, E., The Vapour Pressures of Pure Substances. Second Revised Edition. Amsterdam: Elsevier, 1984.
74 mmHgshownVapor pressure, kPa at 25 °C: 9.9[3] ILO-WHO International Chemical Safety Cards (ICSCs)
73 mmHg73 [mm Hg] @20 °C[7] PAC Chemical Database, U.S. Department of Energy

2 more values were reported but failed the checks (unreadable or out of range), so they are not shown.

Flash point
6 °C (42 °F) (Open Cup)[6]
4 values

3 of 4 sources agree on it (most common value).

ValueAs writtenSource
6 °C42 °F (NTP, 1992)[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
6 °Cshown42 °F (6 °C) (Open Cup)[6] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-10
2 °C2 °C c.c.[3] ILO-WHO International Chemical Safety Cards (ICSCs)
6 °C42 °F (open cup)[4] Occupational Safety and Health Administration (OSHA)

1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.

Autoignition temperature
524 °C[3]
3 values

3 of 3 sources agree on it (most common value).

ValueAs writtenSource
524 °C975 °F (USCG, 1999)[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
524 °C975 °F (524 °C)[6] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-10
524 °Cshown524 °C[3] ILO-WHO International Chemical Safety Cards (ICSCs)
Viscosity
0.35 cP at 20 °C[3]
2 values

2 of 2 sources agree on it (most common value).

ValueAs writtenSource
–0.35 cP at 20 °C[6] Hazardous Substances Data Bank (HSDB)cites DeVito SC; Nitriles. Kirk-Othmer Encyclopedia of Chemical Technology. (1999-2014). New York, NY: John Wiley & Sons. Online Posting Date: Sept 14, 2007.
–shown0.35 cP at 20 °C[3] 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
3
Rings
0
Aromatic rings
0
Fraction sp³ carbons (Fsp3)
0.5
H-bond donors
0
H-bond acceptors
1
Rotatable bonds
0
TPSA (Ų)
23.8
Formal charge
0
XLogP3
0 PubChem
Complexity
29 PubChem
Stereocenters
None
Double-bond geometry
None specified
Point group
C3v of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

  • C58.51%
  • H7.37%
  • N34.12%

Isotope pattern

100%41.0262.6%42.029

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
0.53 Crippen (Wildman and Crippen 1999)
log S (water solubility)
-0.43 ESOL (Delaney 2004), log mol/L
Synthetic accessibility
3.36 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

  • Molecular weight ≤ 500: 41.05
  • log P ≤ 5 (Crippen): 0.53
  • H-bond donors ≤ 5: 0
  • H-bond acceptors ≤ 10: 1

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 [8].

  • Flammable
  • Harmful or irritant
320
NFPA 704[6]
  • H225Highly Flammable liquid and vapor
  • H302Harmful if swallowed
  • H312Harmful in contact with skin
  • H319Causes serious eye irritation
  • H332Harmful if inhaled

Precautionary statements: P210, P233, P240, P241, P242, P243, P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P317, P321, P330, P337+P317, P362+P364, P370+P378, P403+P235, P501

View all classifications (3)
  • [8] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH225, H302, H312, H319, H332
  • [9] European Chemicals Agency (ECHA) · 1,194 reports · DangerH302, H312, H319, H332
  • [6] Hazardous Substances Data Bank (HSDB) · DangerH225, H302, H312, H319, H332

Exposure limits

  • PEL-TWA (8-Hour Time Weighted Average): 40 ppm (70 mg/m³)[4]
  • PEL: TWA 40 ppm (70 mg/m³) See Appendix G[5]
  • REL-TWA (Time Weighted Average): 20 ppm (34 mg/m³)[4]
  • REL: TWA 20 ppm (34 mg/m³)[5]
  • TLV: 20 ppm as TWA; (skin); A4 (not classifiable as a human carcinogen).[3]
  • IDLH: 137 ppm (NIOSH, 2024)[1]

First aid

  • Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]
  • General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[10]
  • (General first aid procedures) Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: Water flush immediately - If this chemical contacts the skin, immediately flush the contaminated skin with water. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water.[5]
  • Fresh air, rest. Artificial respiration may be needed. No mouth-to-mouth artificial respiration. Refer immediately for medical attention.[3]

Storage

  • Fireproof. Keep in a well-ventilated room. Separated from acids, bases, strong oxidants and food and feedstuffs. Well closed.[3]
  • Protect containers against physical damage. Outdoor or detached storage is preferable. Separate from any sources of ignition and combustible materials. Storage room should be well-ventilated.[6]
  • Inside storage should be in a standard flammable liquids storage warehouse, room, or cabinet. Separate from oxidizing materials. Outside or detached storage is preferred.[6]
  • Store in tightly closed containers in a cool, well ventialted area. Metal containers involving the transfer of this chemical should be grounded and bonded. Where possible, automatically pump liquid from drums or other storage containers to process containers. Drums must be equipped with self-closing valves, pressure vacuum bungs; and flame arresters. Use only non-sparking tools and equipment, especially when opening and closing containers of this chemical.[6]

Incompatibilities

  • Strong oxidizers such as chlorine, bromine, and fluorine; chlorosulfonic acid; oleum or sulfuric acid. May accumulate static electricial charges, and may cause ignition of its vapors.[6]
  • Strong oxidizers.[6]
  • Will react with water, steam, acids to produce toxic & flammable vapors.[6]
  • Nitrogen-fluorine compounds are potentially explosive in contact with acetonitrile. ... A solution of an unspecified lanthanide perchlorate in acetonitrile detonated while being heated under reflux.[6]

Safety data sheets on the supplier’s page: Thermo Fisher Scientific, Oakwood Products, VladaChem.

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. [1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
  2. [2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
  3. [3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
  4. [4]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
  5. [5]The National Institute for Occupational Safety and Health (NIOSH) · Public domain (US CDC) · via PubChem · retrieved 2026-10-14
  6. [6]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
  7. [7]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
  8. [8]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
  9. [9]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
  10. [10]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
  11. [11]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
  12. [12]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
  13. [13]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
  14. [14]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
  15. [15]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
  16. [16]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
  17. ·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
  18. ·Literature on PubChem

Data last updated 2026-10-14.