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Ammonia

Athanor · official

H3N · 17.031 g/mol

IUPAC name: azane

Also called NH3, hyperammonaemia, urea cycle

Open in Athanor
The structure of Ammonia
Drawn from its SMILES with RDKit130
Compressed gasCorrosiveAcute toxicityEnvironmental hazardDangerFlammable gas · Causes severe skin burns and eye damage · Toxic if inhaled · Very toxic to aquatic life

Names and identifiers

IUPAC name
azane
Synonyms
NH3, hyperammonaemia, urea cycle
+ 38 more

azane, Ammonia gas, Nitro-sil, Ammonia anhydrous, Ammonia, anhydrous, Anhydrous ammonia, Ammoniak, Liquid Ammonia, AM-Fol, ammoniac, Aqueous ammonia, Refrigerent R717, amoniaco, Ammoniaca, Amoniak, R 717, R 717 (ammonia), Aqua ammonia, Ammonia inhalant, Ammonium causticum, DTXSID0023872, 5138Q19F1X, CHEBI:16134, Ammonia (anhydrous), Inhalant, Smelling Salts, Smelling Salt, Ammonia Pad, Ammonia Inhalants, AmmoniaSport RAW, Ammonia 2%, VYV Smelling Salts, WXMX Smelling Salts, Summit Smelling Salts, AmmoniaSport SQUEEZE, Ammonia (29%), GO TIME, RefChem:6611

Molecular formula
H3N
Empirical formula
H3N
Molecular weight
17.031 g/mol
Exact mass
17.02655
CAS number
7664-41-7
PubChem CID
222
Canonical SMILES
N
Isomeric SMILES
N
InChI
InChI=1S/H3N/h1H3
InChIKey
QGZKDVFQNNGYKY-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity
Appearance
Colorless gas or compressed liquid (compressed under its own pressure)[6]
9 values

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

ValueAs writtenSource
–Ammonia solutions (containing more than 35% but not more than 50% ammonia) appears as a clear colorless liquid consisting of ammonia dissolved in water. Corrosive to tissue and metals. Although ammonia is lighter than air, the vapors from a leak will initially hug the ground. Long term exposure to low concentrations or short term exposure to high concentrations may result in adverse health conditions from inhalation. Prolonged exposure of containers to fire or heat may result in their violent rupturing and rocketing.[1] CAMEO Chemicals
–Ammonia, anhydrous appears as a clear colorless gas with a strong odor. Shipped as a liquid under its own vapor pressure. Density (liquid) 6 lb / gal. Contact with the unconfined liquid can cause frostbite. Gas generally regarded as nonflammable but does burn within certain vapor concentration limits and with strong ignition. Fire hazard increases in the presence of oil or other combustible materials. Although gas is lighter than air, vapors from a leak initially hug the ground. Prolonged exposure of containers to fire or heat may cause violent rupturing and rocketing. Long-term inhalation of [1] CAMEO Chemicals
–Ammonia, solution, with more than 10% but not more than 35% ammonia appears as a colorless aqueous liquid solution with a strong odor of ammonia. Both liquid and vapors extremely irritating, especially to the eyes.[1] CAMEO Chemicals
–Liquid; Gas Vapor; Liquid; Other Solid; Gas Vapor; CBI[2] EPA Chemical Data Reporting (CDR)
–COLOURLESS GAS OR COMPRESSED LIQUEFIED GAS WITH PUNGENT ODOUR.[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–Colorless gas with a pungent, suffocating odor. Often used in aqueous solution.[4] Occupational Safety and Health Administration (OSHA)
–Colorless gas with a pungent, suffocating odor. [Note: Shipped as a liquefied compressed gas. Easily liquefied under pressure.][5] The National Institute for Occupational Safety and Health (NIOSH)
–Clear, colorless, gas. Clear, colorless liquid under pressure.[5] The National Institute for Occupational Safety and Health (NIOSH)
–shownColorless gas or compressed liquid (compressed under its own pressure)[6] Hazardous Substances Data Bank (HSDB)cites NOAA; CAMEO Chemicals. Database of Hazardous Materials. Ammonia, Anhydrous (7664-41-7). Natl Ocean Atmos Admin, Off Resp Rest; NOAA Ocean Serv. Available from, as of Sept 30, 2016: https://cameochemicals.noaa.gov/
Odor
Sharp, cloying, repellent[6]
3 values

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

ValueAs writtenSource
–shownSharp, cloying, repellent[6] Hazardous Substances Data Bank (HSDB)cites Booth, N.H., L.E. McDonald (eds.). Veterinary Pharmacology and Therapeutics. 5th ed. Ames, Iowa: Iowa State University Press, 1982., p. 938
–Pungent, suffocating 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
–Sharp, intensely irritating odor[6] Hazardous Substances Data Bank (HSDB)cites Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 75
Melting point
-77.7 °C (-107.9 °F, EPA 1998)[1]
5 values

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

ValueAs writtenSource
−77.7 °Cshown-107.9 °F (EPA, 1998)[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
−78 °C-78 °C[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−77.7 °C-107.9 °F[4] Occupational Safety and Health Administration (OSHA)
−77.7 °C-77.7 °C[7] PAC Chemical Database, U.S. Department of Energy
−78 °C-108 °F[5] The National Institute for Occupational Safety and Health (NIOSH)
Boiling point
-33.35 °C (-28.03 °F) at 760 mmHg (EPA, 1998)[1]
5 values

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

ValueAs writtenSource
−33.4 °Cshown-28.03 °F at 760 mmHg (EPA, 1998)[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
−33 °C-33 °C[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−33 °C-28 °F[4] Occupational Safety and Health Administration (OSHA)
−33.3 °C-33.3 °C @760 [mm Hg][7] PAC Chemical Database, U.S. Department of Energy
−33 °C-28 °F[5] The National Institute for Occupational Safety and Health (NIOSH)
Density
0.89801 g/L at 20 °C (28% aqueous solution)[6]
7 values

Only one source reports it.

ValueAs writtenSource
–0.6818 at -28.03 °F (EPA, 1998) - Less dense than water[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
0.000771 g/mLDensity: 0.7710 g/L (gas)[6] Hazardous Substances Data Bank (HSDB)cites ATSDR; Toxicological Profile for Ammonia. Atlanta, GA: Agency for Toxic Substances and Disease Registry, US Public Health Service (2004). Available from, as of July 5, 2016: https://www.atsdr.cdc.gov/toxprofiles/index.asp
0.00089801 g/mLshown0.89801 g/L at 20 °C (28% aqueous solution)[6] Hazardous Substances Data Bank (HSDB)cites ATSDR; Toxicological Profile for Ammonia. Atlanta, GA: Agency for Toxic Substances and Disease Registry, US Public Health Service (2004). Available from, as of July 5, 2016: https://www.atsdr.cdc.gov/toxprofiles/index.asp
–Relative density (water = 1): 0.7 (-33 °C)[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–0.6818 at -28.03 °F[4] Occupational Safety and Health Administration (OSHA)
–0.771 @25 °C[7] PAC Chemical Database, U.S. Department of Energy
–0.60(relative gas density)[5] The National Institute for Occupational Safety and Health (NIOSH)
Solubility in water
Solubility in water, g/100ml at 20 °C: 54[3]
5 values

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

ValueAs writtenSource
–34 % (NIOSH, 2024)[1] CAMEO Chemicals
–Soluble in water forming alkaline solutions; soluble in oxygenated solvents.[6] Hazardous Substances Data Bank (HSDB)cites Ashford, R.D. Ashford's Dictionary of Industrial Chemicals. London, England: Wavelength Publications Ltd., 1994., p. 77
–For more Solubility (Complete) data for Ammonia (7 total), please visit the HSDB record page.[6] Hazardous Substances Data Bank (HSDB)
–shownSolubility in water, g/100ml at 20 °C: 54[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–34%[5] The National Institute for Occupational Safety and Health (NIOSH)
log P
log Kow = -2.66 (estimate for ammonium hydroxide which is the form of ammonia in water)[6]
Vapor pressure
7500 mmHg at 25 °C[6]
4 values

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

ValueAs writtenSource
400 mmHg400 mmHg at -49.72 °F (EPA, 1998)[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
7500 mmHgshown7500 mm Hg at 25 °C[6] Hazardous Substances Data Bank (HSDB)cites Daubert TE, Danner RP; Physical and Thermodynamic Properties of Pure Chemicals: Data Compilation. Design Institute for Physical Property Data, American Institute of Chemical Engineers. New York, NY: Hemisphere Pub Corp (1999)
7600 mmHgVapor pressure, kPa at 26 °C: 1013[3] ILO-WHO International Chemical Safety Cards (ICSCs)
7600 mmHg7600 [mm Hg] @25 °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
132 °C (270 °F) - closed cup[6]
Autoignition temperature
651 °C (1204 °F)[6]
3 values

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

ValueAs writtenSource
651 °C1204 °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.
651 °Cshown1204 °F (651 °C)[6] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 49-18
630 °C630 °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
1
Rings
0
Aromatic rings
0
Fraction sp³ carbons (Fsp3)
0
H-bond donors
1
H-bond acceptors
1
Rotatable bonds
0
TPSA (Ų)
35 computed here · PubChem 1
Formal charge
0
XLogP3
-0.7 PubChem
Complexity
0 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

  • H17.76%
  • N82.24%

Isotope pattern

100%17.02618.024

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
0.16 Crippen (Wildman and Crippen 1999)
log S (water solubility)
-0.05 ESOL (Delaney 2004), log mol/L
Synthetic accessibility
6.67 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

  • Molecular weight ≤ 500: 17.03
  • log P ≤ 5 (Crippen): 0.16
  • H-bond donors ≤ 5: 1
  • H-bond acceptors ≤ 10: 1

Passes all four rules.

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].

  • Compressed gas
  • Corrosive
  • Acute toxicity
  • Environmental hazard
130
NFPA 704[6]
  • H221Flammable gas
  • H314Causes severe skin burns and eye damage
  • H331Toxic if inhaled
  • H400Very toxic to aquatic life

Precautionary statements: P210, P260, P261, P264, P271, P273, P280, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P321, P363, P377, P381, P391, P403, P403+P233, P405, P501

View all classifications (4)
  • [8] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH221, H314, H331, H400
  • [9] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for < 0.1% (1 of 3570) of reports.
  • [9] European Chemicals Agency (ECHA) · 3,570 reports · DangerH221, H280, H331, H332, H335, H411
  • [6] Hazardous Substances Data Bank (HSDB) · DangerH221, H280, H314, H318, H331, H400, H410

Exposure limits

  • PEL-TWA (8-Hour Time Weighted Average): 50 ppm (35 mg/m³)[4]
  • PEL: TWA 50 ppm (35 mg/m3) See Appendix G[5]
  • REL-TWA (Time Weighted Average): 25 ppm (18 mg/m³)[4]
  • REL-STEL (Short Term Exposure Limit): 35 ppm (27 mg/m³)[4]
  • REL: TWA 25 ppm (18 mg/m3) ST 35 ppm (27 mg/m3)[5]
  • TLV: 25 ppm as TWA; 35 ppm as STEL.[3]

First aid

  • Excerpt from ERG Guide 125 [Gases - Toxic and/or Corrosive]: Refer to the "General First Aid" section. Specific First Aid: In case of contact with liquefied gas, only medical personnel should attempt thawing frosted parts. In case of skin contact with hydrogen fluoride, anhydrous (UN1052), if calcium gluconate gel is available, rinse 5 minutes, then apply gel. Otherwise, continue rinsing until medical treatment is available. (ERG, 2024)[1]
  • Warning: Ammonia is extremely corrosive to the skin, eyes, and mucous membranes. Contact with the liquified gas may cause frostbite. Caution is advised. Signs and Symptoms of Acute Ammonia Exposure: Inhalation of ammonia may cause irritation and burns of the respiratory tract, laryngitis, dyspnea (shortness of breath), stridor (high-pitched respirations), and chest pain. Pulmonary edema and pneumonia may also result from inhalation. A pink frothy sputum, convulsions, and coma are often seen following exposure to high concentrations.[1]
  • Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]: Refer to the "General First Aid" section. Specific First Aid: For corrosives, in case of contact, immediately flush skin or eyes with running water for at least 30 minutes. Additional flushing may be required. (ERG, 2024)[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]

Storage

  • Fireproof. Separated from oxidants, acids and halogens. Cool. Keep in a well-ventilated room.[3]
  • Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Storage class (TRGS 510): Gases[6]
  • Before entering confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. Protect against physical damage. Outside or detached storage is preferred. Inside storage should be in a cool, well-ventilated, noncombustible location, preferably with automatic monitoring systems, away from all possible sources of ignition. Separate from other chemicals, particularly oxidizing gases, chlorine, bromine, iodine, and acids.[6]
  • Srp: Operations involving entry into tanks or closed vessels, and emergency situations, require consideration of potentially oxygen deficient, or "immediately dangerous to life and health" IDLH environments. This may necessitate use of a self-contained breathing apparatus (SCBA), or a positive pressure supplied air respirator.[6]

Incompatibilities

  • Incompatible materials: Oxidizing agents, iron, zinc, copper, silver/silver oxides, cadmium/cadmium oxides, alcohols, acids, halogens, aldehydes.[6]
  • Shock-sensitive compounds may be formed with gold, halogens, mercury, mercury oxide, and silver oxide.[6]
  • Attacks some coatings, plastics, rubber, copper, brass, bronze. Aluminum, steel, tin, zinc, and their alloys.[6]
  • Potentially violent or explosive reactions on contact with interhalogens (e.g., bromine pentafluoride, chlorine trifluoride), 1,2-dichloroethane (with liquid ammonia), boron halides, chloroformamideium nitrate, ethylene oxide (polymerization reaction), magnesium perchlorate, nitrogen trichloride, oxygen + platinum, or strong oxidants (e.g., potassium chlorate, nitryl chloride, chromyl chloride, dichlorine oxide, chromium trioxide, trioxygen difluoride, nitric acid, hydrogen peroxide, tetramethylammonium amide, thiocarbonyl azide thiocyanate, sulfinyl chloride, thiotriazyl chloride, ammonium…[6]

Safety data sheets on the supplier’s page: 10X CHEM, Accela ChemBio Inc., LGC Standards.

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]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
  13. [13]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
  14. ·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
  15. ·Literature on PubChem

Data last updated 2026-10-14.