Ammonia

"NH3" and "Ammoniac" redirect here. For NH+4, see Ammonium. For the gum ammoniac, see Ammoniacum. For other uses, see NH 3 (disambiguation) and Ammonia (disambiguation).
"R-717" redirects here. For the route in South Africa, see R717 (South Africa).

Ammonia
Stereo structural formula of the ammonia molecule
Ball-and-stick model of the ammonia molecule
Ball-and-stick model of the ammonia molecule
Space-filling model of the ammonia molecule
Space-filling model of the ammonia molecule
Names
IUPAC name
Ammonia[1]
Systematic IUPAC name
Azane
Other names
  • Hydrogen nitride
  • R-717
  • R717 (refrigerant)
  • Amidogen
  • Hydrogen amine
  • Nitrogen hydride
Identifiers
3D model (JSmol)
3DMet
3587154
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.028.760 Edit this at Wikidata
EC Number
  • 231-635-3
79
KEGG
MeSH Ammonia
RTECS number
  • BO0875000
UNII
UN number 1005
  • InChI=1S/H3N/h1H3 checkY
    Key: QGZKDVFQNNGYKY-UHFFFAOYSA-N checkY
  • InChI=1/H3N/h1H3
    Key: QGZKDVFQNNGYKY-UHFFFAOYAF
  • N
Properties
NH3
Molar mass 17.031 g·mol−1
Appearance Colourless gas
Odor Strong pungent odour
Density
  • 0.86 kg/m3 (1.013 bar at boiling point)
  • 0.769 kg/m3 (STP)[2]
  • 0.73 kg/m3 (1.013 bar at 15 °C)
  • 0.6819 g/cm3 at −33.3 °C (liquid)[3] See also Ammonia (data page)
  • 0.817 g/cm3 at −80 °C (transparent solid)[4]
Melting point −77.73 °C (−107.91 °F; 195.42 K) (Triple point at 6.060 kPa, 195.4 K)
Boiling point −33.34 °C (−28.01 °F; 239.81 K)
Critical point (T, P) 132.4 °C (405.5 K), 111.3 atm (11,280 kPa)
  • 530g/l(20 °C)
  • 320g/l(25 °C) [5]
Solubility soluble in chloroform, ether, ethanol, methanol
Vapor pressure 857.3 kPa
Acidity (pKa) 32.5 (−33 °C),[6] 9.24 (of ammonium)
Basicity (pKb) 4.75
Conjugate acid Ammonium
Conjugate base Amide
−18.0×10−6 cm3/mol
1.3327
Viscosity
  • 10.07 µPa·s (25 °C)[7]
  • 0.276 mPa·s (−40 °C)
Structure
C3v
Trigonal pyramid
1.42 D
Thermochemistry
193 J/(mol·K)[8]
−46 kJ/mol[8]
Hazards
GHS labelling:[11]
GHS05: Corrosive GHS06: Toxic GHS09: Environmental hazard
Danger
H314, H331, H410
P260, P273, P280, P303+P361+P353, P304+P340+P311, P305+P351+P338+P310
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazard COR: Corrosive; strong acid or base. E.g. sulfuric acid, potassium hydroxide
3
1
0
COR
651 °C (1,204 °F; 924 K)
Explosive limits 15.0–33.6%
Lethal dose or concentration (LD, LC):
350 mg/kg (rat, oral)[9]
  • 40,300 ppm (rat, 10 min)
  • 28,595 ppm (rat, 20 min)
  • 20,300 ppm (rat, 40 min)
  • 11,590 ppm (rat, 1 hr)
  • 7338 ppm (rat, 1 hr)
  • 4837 ppm (mouse, 1 hr)
  • 9859 ppm (rabbit, 1 hr)
  • 9859 ppm (cat, 1 hr)
  • 2000 ppm (rat, 4 hr)
  • 4230 ppm (mouse, 1 hr)[10]
  • 5000 ppm (mammal, 5 min)
  • 5000 ppm (human, 5 min)[10]
NIOSH (US health exposure limits):[12]
PEL (Permissible)
 50 ppm (25 ppm ACGIH-TLV; 35 ppm STEL)
REL (Recommended)
 TWA 25 ppm (18 mg/m3) ST 35 ppm (27 mg/m3)
IDLH (Immediate danger)
 300 ppm
Safety data sheet (SDS) ICSC 0414 (anhydrous)
Related compounds
Related nitrogen hydrides
Related compounds
Supplementary data page
Ammonia (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the formula NH3. A stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pungent smell. Biologically, it is a common nitrogenous waste, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to fertilisers.[13] Around 70% of ammonia produced industrially is used to make fertilisers[14] in various forms and composition, such as urea and diammonium phosphate. Ammonia in pure form is also applied directly into the soil.

Ammonia, either directly or indirectly, is also a building block for the synthesis of many chemicals.

Ammonia occurs in nature and has been detected in the interstellar medium. In many countries, it is classified as an extremely hazardous substance.[15]

Ammonia is produced biologically in a process called nitrogen fixation, but even more is generated industrially by the Haber process. The process helped revolutionize agriculture by providing cheap fertilizers. The global industrial production of ammonia in 2021 was 235 million tonnes.[16][17] Industrial ammonia is transported by road in tankers, by rail in tank wagons, by sea in gas carriers, or in cylinders.[18]

Ammonia boils at −33.34 °C (−28.012 °F) at a pressure of one atmosphere, but the liquid can often be handled in the laboratory without external cooling. Household ammonia or ammonium hydroxide is a solution of ammonia in water.

  1. ^ "Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005" (PDF). Archived (PDF) from the original on 9 October 2022.
  2. ^ "Gases – Densities". The Engineering Toolbox. Retrieved 3 March 2016.
  3. ^ Yost, Don M. (2007). "Ammonia and Liquid Ammonia Solutions". Systematic Inorganic Chemistry. Read Books. p. 132. ISBN 978-1-4067-7302-6.
  4. ^ Blum, Alexander (1975). "On crystalline character of transparent solid ammonia". Radiation Effects and Defects in Solids. 24 (4): 277. Bibcode:1975RadEf..24..277B. doi:10.1080/00337577508240819.
  5. ^ "Ammonia". The American Chemical Society. 8 February 2021. Retrieved 20 March 2024.
  6. ^ Perrin, D. D. (1982). Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution (2nd ed.). Oxford: Pergamon Press.
  7. ^ Iwasaki, Hiroji; Takahashi, Mitsuo (1968). "Studies on the transport properties of fluids at high pressure". The Review of Physical Chemistry of Japan. 38 (1).
  8. ^ a b Zumdahl, Steven S. (2009). Chemical Principles (6th ed.). Houghton Mifflin. p. A22. ISBN 978-0-618-94690-7.
  9. ^ "Ammonia, Anhydrous Safety Data Sheet" (PDF). University of Florida. Retrieved 19 April 2024.
  10. ^ a b "Ammonia". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  11. ^ Sigma-Aldrich Co., Ammonia.
  12. ^ NIOSH Pocket Guide to Chemical Hazards. "#0028". National Institute for Occupational Safety and Health (NIOSH).
  13. ^ Ritchie, Hannah. "How many people does synthetic fertilizer feed?". Our World in Data. Retrieved 4 September 2021.
  14. ^ "Ammonia Technology Roadmap – Analysis". IEA. 11 October 2021.
  15. ^ "40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities". United States: Government Printing Office.
  16. ^ "Global ammonia annual production capacity". Statistia.
  17. ^ "Mitsubishi Heavy Industries BrandVoice: Scaling Ammonia Production for the World's Food Supply". Forbes. 29 October 2021.
  18. ^ Shreve, R. Norris; Brink, Joseph (1977). Chemical Process Industries (4th ed.). McGraw-Hill. p. 276. ISBN 978-0-07-057145-7.