Summary
Ammonia (NH₃) is a simple molecule—one nitrogen atom and three hydrogen atoms. It occurs naturally in the nitrogen cycle, has been produced, stored and shipped at industrial scale for more than a century, and today is essential to food production and many industries. It’s colorless with a sharp smell, highly soluble in water, and—while toxic at high concentrations—well understood and safely handled under proven standards.
Key facts
Property | Value / Behavior | Why it matters |
---|---|---|
Chemical formula | NH₃ (one nitrogen + three hydrogen atoms) | Defines the molecule used across fertilizer, industry, and energy. |
State & odor | Colorless gas with a sharp, recognizable smell | Early human detection at low levels helps people move away quickly. |
Boiling point | −33 °C (−28 °F) | Liquefies under moderate pressure/cooling—useful for storage and shipping. |
Solubility | Highly soluble in water (forms ammonium hydroxide) | Important for handling procedures and emergency response design. |
Relative density (gas) | Typically lighter than air when warm; cold releases can form a visible aerosol cloud | Explains why plumes may rise in warm conditions or hug the ground when cold. |
Flammability | Narrow flammable range in air (~15–28% by volume); high ignition energy | Lower open-air fire/explosion risk vs. many hydrocarbons; confined-space risks still engineered for. |
Human exposure cues | Odor noticeable at low ppm; IDLH reference: 300 ppm | Guides workplace limits, detection, and PPE planning. |
Global scale today | ~150–180 million tonnes produced per year (majority for fertilizers) | Shows the maturity of production, storage, and transport infrastructure. |
Ammonia in nature
Ammonia itself is also naturally present in the environment. As an important nitrogen source for plants and animals, it is an essential nutrient for sustaining life on Earth. It plays a major role in the so-called nitrogen cycle – the process where nitrogen converts into different forms, repeatedly passing from the atmosphere to the soil to organisms and eventually returning to the atmosphere.
In short—how the nitrogen cycle works
- Nitrogen fixation: Lightning and certain bacteria convert atmospheric N2 into ammonium/ammonia in soil or root nodules.
- Assimilation: Plants take up ammonium and nitrate and turn them into proteins and chlorophyll; animals get nitrogen by eating plants.
- Ammonification: Decomposers break down dead material and manure, releasing ammonium back into the soil.
- Nitrification: Soil bacteria convert ammonium → nitrite → nitrate, a highly plant-available form that can also leach with water.
- Denitrification: In wet/low-oxygen zones, bacteria turn nitrate back into N2 (and small amounts of N2O), closing the loop.
Why it matters: Healthy soils and good nutrient management keep more nitrogen in crops and less lost to air or water.