Ammonium chloride crystallizes in the crystal lattice of cesium iodide, but at 184° C it turns into the crystal lattice of sodium chloride.
The ammonium chloride compound dissolves well in water with cooling the resulting solution, but is hardly soluble in organic solutions. It can be stored easily because its crystals do not clump together or leak. The watery solutions of ammonium chloride are acidic (a solution 1% has a PH= 5.3). Heating up to 338° C leads to heat the ammonium chloride, and the resulting steam decomposes into ammonia and hydrogen chloride.
It is widely used as a conductive medium for ions in dry batteries. Ammonium chloride is used in metal welding processes where ammonium chloride breaks down at the hot end of the barbecue rod to release hydrogen chloride which is effective against metal oxides and other impurities on the metal surface, especially in the presence of ammonia which leads to a better welding process.
In medicine, it is used in the preparation of sputum solutions.