Ammonium phosphate

Ammonium phosphate is the inorganic compound with the formula (NH₄)₃PO₄. It is the ammonium salt of orthophosphoric acid. A related "double salt", (NH₄)₃PO₄^.(NH₄)₂HPO₄ is also recognized but is impractical to use. Both triammonium salts evolve ammonia. In contrast to the unstable nature of the triammonium salts, the diammonium phosphate (NH₄)₂HPO₄ and monoammonium salt (NH₄)H₂PO₄ are stable materials that are commonly used as fertilizers to provide plants with fixed nitrogen and phosphorus.^[3]

Ammonium phosphate^[1]

Ball-and-stick model of three ammonium cations and one phosphate anion
Names
IUPAC name ammonium phosphate
Other names triammonium phosphate
Identifiers
CAS Number	10361-65-6  Y
3D model (JSmol)	Interactive image
ChemSpider	140090 Y
ECHA InfoCard	100.030.709
EC Number	269-789-9
PubChem CID	159282
UNII	2ZJF06M0I9 N
CompTox Dashboard (EPA)	DTXSID8052778
InChI InChI=1S/3H3N.H3O4P/c;;;1-5(2,3)4/h3*1H3;(H3,1,2,3,4) Y Key: ZRIUUUJAJJNDSS-UHFFFAOYSA-N Y InChI=1/3H3N.H3O4P/c;;;1-5(2,3)4/h3*1H3;(H3,1,2,3,4) Key: ZRIUUUJAJJNDSS-UHFFFAOYAA
SMILES [O-]P([O-])([O-])=O.[NH4+].[NH4+].[NH4+]
Properties
Chemical formula	(NH4)3PO4
Molar mass	149.09 g/mol
Appearance	White, tetrahedral crystals
Solubility in water	58.0 g/100 mL (25 °C)
Solubility	Insoluble in acetone[2]
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H319
Precautionary statements	P264, P270, P280, P301+P312, P305+P351+P338, P330, P337+P313, P501
NFPA 704 (fire diamond)	2 0 0
Thermochemistry
Std enthalpy of formation (ΔfH⦵298)	−1671.9 kJ/mol
Related compounds
Other cations	Trisodium phosphate Tripotassium phosphate
Related compounds	Diammonium phosphate Monoammonium phosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Ammonium phosphate is the main ingredient in pink fire retardant. ^[4]

Preparation of triammonium phosphate

Triammonium phosphate can be prepared in the laboratory by treating 85% phosphoric acid with 30% ammonia solution:^{[citation needed]}

H₃PO₄ + 3 NH₃ → (NH₄)₃PO₄

(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.

See also

• Ammonium polyphosphate
• Monoammonium phosphate
• Diammonium phosphate