Ammonium chloride is a combination of ammonia and chlorine. The modern name "ammonium" comes from sal ammoniac. The substance was known as nushadir salt. The Romans called the ammonium chloride deposits they collected from near the Temple of Jupiter Amun. In nature, the substance occurs in volcanic regions, forming on volcanic rocks near fume-releasing vents. The crystals deposit directly from the gaseous state, and tend to be short-lived, as they dissolve easily in water. Ammonium chloride is prepared commercially by reacting ammonia, NH3, with hydrogen chloride, HCl.

It is an acid whose effects are undesirable in acidic soil. It is sold in blocks at hardware stores for use in cleaning the tip of a soldering iron and can also be included in solder as flux.

It can be used to feed to cattle as supplement, in hair shampoo, in textile printing, in the glue that bonds plywood, as an ingredient in nutritive media for yeast, in cleaning products and as cough medicine. Ammonium chloride is used in snow treatment, namely on ski slopes at temperatures above 0°C, to harden the snow and slow its melting.