Ammonium Phosphate - (NH4)3PO4

What is Ammonium phosphate?

Ammonium phosphate is an unstable compound made of ammonium and phosphate salt with the chemical formula (NH4)3PO4.

Ammonium phosphate is manufactured by mixing together ammonium phosphate and urea in a molten condition. Considerable heat is generated which transform the ammonium phosphate to the molten state. It includes a group of nitrogen phosphorus materials: mono ammonium phosphates and diammonium phosphates, mixtures of the two or combinations with ammonium nitrate or ammonium sulfate.

Other names – triammonium phosphate, diazanium hydrogen phosphate

Table of Contents

Ammonium phosphate Structure – (NH4)3PO4

Ammonium phosphate

General Properties of Ammonium phosphate – (NH4)3PO4

(NH4)3PO4 Ammonium phosphate
Density 1.619 g/cubic cm
Molecular Weight/ Molar Mass 149.09 g/mol
Boiling Point 130°C
Melting Point 155 °C (311 °F; 428 K) decomposes
Chemical Formula H9N2O4P

Physical Properties of Ammonium phosphate – (NH4)3PO4

Odour Ammonia odour
Appearance White, tetrahedral crystals
Complexity 46.5
Covalently-Bonded Unit 3
Hydrogen Bond Donor 3
Solubility Readily soluble in water
Solubility pH 4 to 4.5

Chemical Properties of Ammonium phosphate – (NH4)3PO4

    • Ammonium phosphate readily undergoes a decomposition reaction, emitting very toxic fumes. It forms phosphoric acid and ammonia.

(NH4)3PO4 → 3NH3 + H3PO4

    • Ammonium phosphate reacts with lead nitrate forming lead phosphate and ammonium nitrate.

4(NH4)3PO4 + 3Pb(NO3)4 → Pb3(PO4)4 + 12NH4NO3

Uses of Ammonium phosphate – (NH4)3PO4

  • Ammonium phosphate is a broad generic name for a variety of fertilizer materials containing both nitrogen and phosphate.
  • Ammonium phosphates are becoming increasingly important as a source of available P2O5. P2O5 is somewhat higher in ammonium phosphates than in triple superphosphate.
  • Mainly used as a solid fertilizer but can also be utilized in solution.
  • Used as components of intumescent paints and mastics where they function as an acid catalyst.
  • Used in paints in which pentaerythritol is the carbonific component and melamine is the specific compound.

Frequently Asked Questions – FAQs


What is ammonium phosphate used for?

Ammonium phosphate is a high source of elemental nitrogen used as an ingredient in certain fertilizers. This is also used in thermoplastic formulations as a flame retardant.


What is ammonium phosphate fertilizer?

Ammonium phosphate adds nitrogen and phosphates to the lawns which lack the nutrients. Ammonium phosphate is a fast-release fertilizer that can be used for new grass planting, cleaning, monitoring, or lawn renovation.


What’s the difference between ammonia and ammonium?

Ammonia contains one nitrogen and three hydrogens opposed to one nitrogen and four hydrogens formed by ammonium. Ammonia is a low, unionized foundation. In the other side, it is ionized to ammonium. Some major distinctions between the two is that Ammonia gives off a heavy odour while Ammonium does not smell at all.


Is ammonium phosphate an acid?

Ammonium phosphate is an orthophosphoric acid ammonium salt. Formula (NH4)3PO4 is a highly unstable compound. It is elusive, and of little economic interest due to its uncertainty.


Why is ammonium phosphate soluble in water?

It is soluble in water, and ammonia loses and the acid phosphate (NH4)(H2PO4) is formed as the aqueous solution on the boil. Ammonium phosphate is a high source of elemental nitrogen used as an ingredient in certain fertilizers. This is also used in thermoplastic formulations as a flame retardant.

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