Ammonium phosphate

Ammonium phosphate^[1]

Names
IUPAC name ammonium phosphate
Other names triammonium phosphate
Identifiers
CAS Number	10361-65-6
ChemSpider	140090
Jmol 3D model	Interactive image
InChI InChI=1S/3H3N.H3O4P/c;;;1-5(2,3)4/h3*1H3;(H3,1,2,3,4) Key: ZRIUUUJAJJNDSS-UHFFFAOYSA-N 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	H12N3O4P
Molar mass	149.09 g·mol^−1
Appearance	White, tetrahedral crystals
Solubility in water	58.0 g/100 mL (25 °C)
Hazards
NFPA 704	0 2 0
Thermochemistry
Std enthalpy of formation (ΔfH^o298)	−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).
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Infobox references

Ammonium phosphate is the salt of ammonium and phosphate. It is a highly unstable compound with the formula (NH₄)₃PO₄. Because of its instability, it is elusive and of no commercial value (except for scientific research). In addition to (NH₄)₃PO₄, a related double salt (NH₄)₃PO₄.(NH₄)₂HPO₄ is also recognized. It too is unstable. The instability of these salts results of their facile decomposition with evolution of ammonia:^[2]

(NH₄)₃PO₄ → H(NH₄)₂PO₄ + NH₃

In contrast to the fragile nature of the triammonium salts, diammonium phosphate (H(NH₄)₂PO₄) is a valuable material, mainly used as a fertilizer.

See also

• Ammonium polyphosphate
• Monoammonium phosphate
• Diammonium phosphate

References

1. Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 4–42, 5–19. ISBN 0-8493-0594-2.
2. Klaus Schrödter, Gerhard Bettermann, Thomas Staffel, Friedrich Wahl, Thomas Klein, Thomas Hofmann "Phosphoric Acid and Phosphates" in Ullmann’s Encyclopedia of Industrial Chemistry 2008, Wiley-VCH, Weinheim. doi:10.1002/14356007.a19_465.pub3