Chemistry Formulas

Ammonium Phosphate Formula

Ammonium phosphate is the salt of two substances that are the ammonium and phosphate. Moreover, it is highly unstable and it is a compound that has the formula (NH4)3PO4. Because of its instability, it is elusive and it does not have any commercial value. A related “double salt”, (NH4)3PO4.(NH4)2HPO4 is also present there but it is too unstable for any practical use. Moreover, both the triammonium salts evolve the ammonia. In respect of the fragile nature of the triammonium salts, the diammonium phosphate (NH4)2HPO4, the monoammonium salt (NH4)H2PO4, is the stable materials that are commonly useful in the form of fertilizers to provide plants with a set amount of nitrogen and phosphorus. Let’s study about the Ammonium Phosphate Formula below.

Structure and Formula

The molecular formula for the ammonium phosphate is (NH4)3PO4. And the structure of the ammonium phosphate is present below in the form of an image:

Ammonium Phosphate Formula


The production of the ammonium phosphate (NH4H2PO4) takes place by the process of reacting phosphoric acid (H3PO4) with the anhydrous ammonia (NH3):

NH3 + H3PO4 → NH4H2PO4

On the other hand, ammoniated superphosphates are made by the process of adding normal superphosphates or triple superphosphates in the mixture. However, we can call the production of the liquid ammonium phosphate and ammoniated superphosphates in fertilizer mixing plants as a separate process.


It is obtained in the form of a crystalline powder upon mixing concentrated solutions of the ammonia and the phosphoric acid or on the addition of a large amount of the ammonia to the acid phosphate i.e. (NH4)2(HPO4). It is soluble when putting inside the water, and the aqueous solution loses ammonia on boiling and the formation of the acid phosphate takes place i.e. (NH4)(H2PO4).

Physical Properties

The ammonium phosphate has an odour of the ammonia in it. Moreover, it is of white colour in appearance and is in the form of white colour tetrahedral crystals. The level of complexity of the ammonium phosphate is 46.5. Whereas, the Covalently-Bonded Unit is 3. The numbers of the Hydrogen Bond Donor in the ammonium sulphate is 3. On the other hand, the ammonium sulphate is easily soluble when we put it inside the water (H2O). It has a pH of about 4 to 4.5.

Chemical Properties

The ammonium phosphate undergoes the process of the decomposition reaction that is emitting very toxic fumes. Moreover, through this the formation of the phosphoric acid and ammonia takes place.

(NH4)3PO4 → 3NH3 + H3PO4

The ammonium phosphate reacts with the lead nitrate that results in forming of lead phosphate and ammonium nitrate.

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


Ammonium phosphate is much popular and it is a broad generic name for a variety of fertiliser materials that contain both nitrogen and phosphate at the same time. The ammonium phosphates are now becoming increasingly important as a source of available P2O5. However, the P2O5 is somewhat higher in the ammonium phosphates than in the triple superphosphate.

It is mainly useful as a solid fertilizer but we can also use it in the solution. Moreover, it comes in use as the components of intumescent paints and mastics where they perform as an acid catalyst. These are also used in paints which are the pentaerythritol as the carbonific components and melamine as the spumific compounds.

Safety Hazards

The ammonium phosphate may cause eye irritation. Moreover, it can also harm the skin or can cause skin irritation also. It can also be a reason behind the gastrointestinal irritation with nausea, vomiting, and diarrhea at the same time. Inhalation problems might occur and it can also cause respiratory tract irritation if not handled carefully.

Solved Example for You:

Question: A sample of ammonium phosphate, (NH4)3PO4 contains 3.18 mol of hydrogen atoms. The number of moles of oxygen atoms in the sample will be:

(A). 0.265

(B). 0.795

(C). 1.06

(D). 3.18

Answer: (C). 1.06

Solution: (NH4)3PO4

12 mol hydrogen atom contains = 4 atoms of oxygen

1 mol hydrogen atom contains 412

3.18 mol hydrogen atom contain =412×3.18=1.08mole.

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