ammoniae

Ammoniae is a term encountered in some historical or Latin-language sources as a form related to ammonia. In modern usage, the standard term is ammonia, with chemical formula NH3, and ammoniae is not common in current scientific literature. The substance described by ammoniae is the same chemical species known as ammonia.

Ammonia is a colorless gas with a pungent odor. It is highly soluble in water, where it forms ammonium hydroxide (NH4OH), a weak base. In aqueous solution, ammonia acts as a Brønsted–Lowry base by accepting a proton to give NH4+ and OH−. Its conjugate acid, the ammonium ion, has a pKa around 9.25, corresponding to a pKb for NH3 of about 4.75. At room temperature, ammonia has a boiling point of −33.3 °C and is typically encountered as a gas, although it is readily liquefied under pressure. It is lighter than air and is highly reactive with acids and many oxidizers.

Industrial production of ammonia is dominated by the Haber–Bosch process, which combines nitrogen and hydrogen (the latter often sourced from natural gas via steam reforming) over an iron catalyst at high pressure and temperature to yield NH3. Ammonia is a key feedstock for fertilizers (e.g., anhydrous ammonia, ammonium sulfate, ammonium nitrate) and for urea production, as well as a precursor in the synthesis of nitric acid via the Ostwald process. It also serves as a cleaning agent and a reagent in various chemical syntheses.

In the environment, ammonia occurs in trace amounts in soil and water and is produced by microbial activity and decomposition. It can be irritating and caustic to skin, eyes, and the respiratory tract, and handling requires appropriate safety measures.