Ammonium dihydrogen phosphate (ADP), also known as monoammonium phosphate (MAP), is formed when a solution of phosphoric acid is added to ammonia until the solution is distinctly acidic. It crystallizes in tetragonal prisms.
A 2128 (OTTO) Ammonium dihydrogenphosphate, for HPLC 99% Cas 7722-76-1 - used in an emerald green, amethyst and aquamarine crystal growing box kit for children.