Some chemical/physical properties of ammonia are:
- At room temperature, ammonia is a colorless, highly irritating gas with a pungent, suffocating odor
- In pure form, it is known as anhydrous ammonia and is hygroscopic (readily absorbs moisture)
- Ammonia has alkaline properties and is corrosive
- Ammonia gas dissolves easily in water to form ammonium hydroxide, a caustic solution and weak base
- Ammonia gas is easily compressed and forms a clear liquid under pressure
- Its usually shipped as a compressed liquid in steel containers
- Ammonia is not highly flammable, but containers of ammonia may explode when exposed to high heat
Ammonia can be easily liquefied under 1 atm at −33 °C or under 10 atm at 20 °C, while hydrogen needs very low temperature (−253 °C) or high pressure (250 atm).
In addition, ammonia provides higher volumetric density than hydrogen.
Several firms are developing green ammonia, a route to ammonia in which hydrogen derived from water electrolysis powered by alternative energy replaces hydrocarbon-based hydrogen, making ammonia production virtually carbon dioxide–free.
But establishing an ammonia fuel industry won’t be easy.
By most estimates, green ammonia will cost 2 to 4 times as much to make as conventional ammonia.
And some of the technologies needed to harness the molecule, such as ammonia-burning engines, are still experimental.