3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||149.09 g/mol|
|Appearance||White, tetrahedral crystals|
|58.0 g/100 mL (25 °C)|
|GHS Signal word||Warning|
|P264, P270, P280, P301+312, P305+351+338, P330, P337+313, P501|
|NFPA 704 (fire diamond)|
Std enthalpy of
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|(what is ?)|
Ammonium phosphate is an ammonium salt of orthophosphoric acid. It is a highly unstable compound with the formula (NH4)3PO4. Because of its instability, it is elusive and of no commercial value. A related "double salt", (NH4)3PO4.(NH4)2HPO4 is also recognized but is too unstable for practical use. Both triammonium salts evolve ammonia. In contrast to the unstable nature of the triammonium salts, the diammonium phosphate (NH4)2HPO4 monoammonium salt (NH4)H2PO4, are stable materials that are commonly used as fertilizers to provide plants with fixed nitrogen and phosphorus.
Triammonium phosphate can be prepared in the laboratory by treating 85% phosphoric acid with 30% ammonia solution:
(NH4)3PO4 is a colorless, crystalline solid. The solid, which has the odor of ammonia, is readily soluble in water. The salt converts to diammonium hydrogen phosphate (NH4)2HPO4.