**Chemical Properties and Reactions**:
– Ammonia is a colorless gas with a pungent smell, lighter than air, and liquefies easily due to strong hydrogen bonding.
– Its solid form has cubic crystal symmetry, and the liquid form has strong ionizing powers and can be used as a solvent.
– Ammonia is amphoteric, acting as a weak base that forms ammonium salts and reacts with acids.
– It has specific redox properties, with a narrow range of stability in liquid ammonia solutions and slow oxidation and reduction rates.
– The solubility of salts in liquid ammonia varies, with most ammonium salts being soluble and acting as acids.
**Applications and Uses**:
– Approximately 88% of ammonia in the US is used as fertilizer, and it is also used in explosives production, synthesis of urea, and various organonitrogen compounds.
– Ammonia is a precursor to many nitrogen-containing compounds and inorganic nitrogenous compounds like nitric acid and hydrazine.
– It is used in water purification systems, as a refrigerant in industrial and space applications, and as an antimicrobial agent in food products.
– Ammonia is considered a potential fuel alternative due to its high energy density and ease of storage, with proposed applications in internal combustion engines.
– Additionally, ammonia has been used historically as a cleansing agent in households and manufacturing cleaning products.
**Industrial and Environmental Impact**:
– Ammonia is a by-product in coking wastewater streams, posing environmental challenges when discharged into marine environments.
– Its toxicity can lead to unexplained losses in fish hatcheries and aquatic environments, affecting fish metabolism and health.
– Ammonia is classified as dangerous for the environment, contributing to fine particulate matter formation and pollution.
– Proper disposal methods for ammonia in coking wastewater and aquaculture systems are crucial to mitigate its environmental impact.
– Ammonia storage requires specific considerations to prevent corrosion and ensure safe containment.
**History and Production**:
– Ammonia has a historical significance, with mentions by Pliny and Jabir ibn Hayyan, and was first isolated by Joseph Black in 1756.
– Industrial production of ammonia was pioneered by Fritz Haber and Robert LeRossignol using the Haber-Bosch process, leading to Haber’s Nobel Prize in Chemistry.
– Ammonia is a critical precursor to various compounds, including nitric acid, amines, and metal ammine complexes, and is used in the synthesis of numerous organic compounds.
– Detection and determination methods for ammonia include Nesslers solution and sulfur sticks, with exposure limits set at 25ppm for safety.
– Ammonia has played a significant role in the development of various chemical processes and applications.
**Toxicity and Safety**:
– While ammonia solutions are generally safe for humans due to physiological mechanisms, they can be highly toxic to aquatic animals like fish and amphibians.
– Ammonia is present in tobacco smoke and is a key environmental pollutant, contributing to fine particulate matter formation.
– Safety concerns exist regarding the use of anhydrous ammonia as an antimicrobial agent in food products.
– Proper handling and disposal of ammonia are essential to prevent environmental contamination and ensure safety in various industrial and household applications.
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. Around 70% of ammonia produced industrially is used to make fertilisers in various forms and composition, such as urea and diammonium phosphate. Ammonia in pure form is also applied directly into the soil.
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| Names | |||
|---|---|---|---|
| IUPAC name
Ammonia
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| Systematic IUPAC name
Azane | |||
Other names
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| Identifiers | |||
3D model (JSmol)
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| 3DMet | |||
| 3587154 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| ECHA InfoCard | 100.028.760 | ||
| EC Number |
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| 79 | |||
| KEGG | |||
| MeSH | Ammonia | ||
PubChem CID
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| RTECS number |
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| UNII | |||
| UN number | 1005 | ||
CompTox Dashboard (EPA)
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| Properties | |||
| NH3 | |||
| Molar mass | 17.031 g·mol−1 | ||
| Appearance | Colourless gas | ||
| Odor | Strong pungent odour | ||
| Density |
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| 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) | ||
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| Solubility | soluble in chloroform, ether, ethanol, methanol | ||
| Vapor pressure | 857.3 kPa | ||
| Acidity (pKa) | 32.5 (−33 °C), 9.24 (of ammonium) | ||
| Basicity (pKb) | 4.75 | ||
| Conjugate acid | Ammonium | ||
| Conjugate base | Amide | ||
| −18.0×10−6 cm3/mol | |||
Refractive index (nD)
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1.3327 | ||
| Viscosity |
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| Structure | |||
| C3v | |||
| Trigonal pyramid | |||
| 1.42 D | |||
| Thermochemistry | |||
Std molar
entropy (S⦵298) |
193 J/(mol·K) | ||
Std enthalpy of
formation (ΔfH⦵298) |
−46 kJ/mol | ||
| Hazards | |||
| GHS labelling: | |||
   
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| Danger | |||
| H280, H314, H331, H410 | |||
| P260, P273, P280, P303+P361+P353, P304+P340+P311, P305+P351+P338+P310 | |||
| 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): | |||
LD50 (median dose)
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0.015 mL/kg (human, oral) | ||
LC50 (median concentration)
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LCLo (lowest published)
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5000 ppm (mammal, 5 min) 5000 ppm (human, 5 min) | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible)
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50 ppm (25 ppm ACGIH- TLV; 35 ppm STEL) | ||
REL (Recommended)
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TWA 25 ppm (18 mg/m3) ST 35 ppm (27 mg/m3) | ||
IDLH (Immediate danger)
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300 ppm | ||
| Safety data sheet (SDS) | ICSC 0414 (anhydrous) | ||
| Related compounds | |||
Related nitrogen hydrides
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Hydrazine Hydrazoic acid | ||
Related compounds
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| 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).
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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.
Ammonia is common in nature, both terrestrially and in the outer planets of the Solar System. It is widely used in dilute form, but is both caustic and hazardous in its concentrated form. In many countries it is classified as an extremely hazardous substance, and is subject to strict reporting requirements by facilities that produce, store, or use it in significant quantities.
The global industrial production of ammonia in 2021 was 235 million tonnes. Industrial ammonia is sold either as ammonia liquor (usually 28% ammonia in water) or as pressurised or refrigerated anhydrous liquid ammonia transported in tank cars or cylinders.
Because of the chemical inertness of nitrogen gas, production of ammonia from atmospheric nitrogen is difficult. Biological nitrogen fixation is only performed by a few families of microorganisms, the diazotrophs. The Haber process that enabled industrial production was invented at the beginning of the 20th century, revolutionizing agriculture.
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% of ammonia by weight at 15.5 °C or 59.9 °F) being the typical high-concentration commercial product.