Ammonium phosphate. The normal phosphate, (NH₄)₃PO₄,is obtained as a crystalline powder, on mixing concentrated solutions of ammonia and phosphoric acid, or on the addition of excess of ammonia to the acid phosphate (NH₄)₂HPO₄. It is soluble in water, and the aqueous solution on boiling loses ammonia and the acid phosphate NH₄H₂PO₄ is formed. In chemistry, a phosphate is a polyatomic ion or radical consisting of one phosphorus atom and four oxygen. ... Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is a weak mineral acid with the chemical formula H3PO4. ... Ammonia is a chemical compound with the formula NH3. ...

Diammonium hydrogen phosphate, (NH₄)₂HPO₄, is formed by evaporating a solution of phosphoric acid with excess of ammonia. It crystallizes in large transparent prisms, which melt on heating and decompose, leaving a residue of metaphosphoric acid, (HPO₃).

Ammonium dihydrogen phosphate, or monoammonium phosphate, NH₄•H₂PO₄, is formed when a solution of phosphoric acid is added to ammonia until the solution is distinctly acid. It crystallizes in quadratic prisms. Monoammonium phosphate is a component of the ABC powder in some dry powder fire extinguishers. Fire extinguisher A fire extinguisher is a device used to put out a fire, often in an emergency situation. ...