Ammonia

Ammonia
Ball-and-stick 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 (refrigerant)

R717 (refrigerant alternative spelling)
Identifiers
3D model (JSmol)
3DMet
3587154
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.028.760
EC Number
  • 231-635-3
79
KEGG
MeSH Ammonia
RTECS number
  • BO0875000
UNII
UN number 1005
  • InChI=1S/H3N/h1H3 Y
    Key: QGZKDVFQNNGYKY-UHFFFAOYSA-N Y
  • InChI=1/H3N/h1H3
    Key: QGZKDVFQNNGYKY-UHFFFAOYAF
  • N
Properties
NH3
Molar mass 17.031 g/mol
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)
681.9 kg/m3 at −33.3 °C (liquid)[3] See also Ammonia (data page)
817 kg/m3 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)
47% w/w (0 °C)
31% w/w (25 °C)
18% w/w (50 °C)[5]
Solubility soluble in chloroform, ether, ethanol, methanol
Vapor pressure 857.3 kPa
Acidity (pKa) 32.5 (−33 °C),[6] 10.5 (DMSO)
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−1·K−1[8]
−46 kJ·mol−1[8]
Hazards
Safety data sheet See: data page
ICSC 0414 (anhydrous)
GHS pictograms [9]
GHS Signal word Danger
H290, H301, H311, H314, H330, H334, H336, H360, H362, H373, H400
P202, P221, P233, P261, P263, P271, P273, P280, P305+351+338, P310[9]
NFPA 704 (fire diamond)
Flash point 132 °C (270 °F; 405 K)
651 °C (1,204 °F; 924 K)
Explosive limits 15,0–33,6%
Lethal dose or concentration (LD, LC):
0.015 mL/kg (human, oral)
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):[11]
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
Related compounds
Other cations
Phosphine
Arsine
Stibine
Bismuthine
Related nitrogen hydrides
Hydrazine
Hydrazoic acid
Related compounds
Ammonium hydroxide
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solidliquidgas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

Ammonia is a 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 distinct pungent smell. It is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45 percent of world's food[12] and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water.

Although common in nature  both terrestrially and in the outer planets of the solar system  and in wide use, ammonia is both caustic and hazardous in its concentrated form. It is classified as an extremely hazardous substance in the United States, and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.[13]

The global industrial production of ammonia in 2018 was 175 million tonnes,[14] with no significant change relative to the 2013 global industrial production of 175 million tonnes.[15] Industrial ammonia is sold either as ammonia liquor (usually 28% ammonia in water) or as pressurized or refrigerated anhydrous liquid ammonia transported in tank cars or cylinders.[16]

NH3 boils at −33.34 °C (−28.012 °F) at a pressure of one atmosphere, so the liquid must be stored under pressure or at low temperature. Household ammonia or ammonium hydroxide is a solution of NH3 in water. The concentration of such solutions is measured in units of the Baumé scale (density), with 26 degrees Baumé (about 30% (by weight) ammonia at 15.5 °C or 59.9 °F) being the typical high-concentration commercial product.[17]