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

Other name – triammonium phosphate, diazanium hydrogen phosphate

(NH4)3PO4 Ammonium phosphate
Density 1.619 g/cu 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

Ammonium phosphate Structure

Ammonium phosphate

Physical Properties of Ammonium phosphate – (NH4)3PO4

Odour Ammonia odor
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 decomposition reaction emitting very toxic fumes. It formes 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 fertiliser 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 which pentaerythritol as the carbonific component and melamine as the spumific compound.

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