Ammonium nitrate has the chemical formula NH₄NO₃. Produced as small porous pellets, or “prills”, it’s one of the world’s most widely used fertilisers.

What is ammonium nitrate? Ammonium nitrate is a chemical compound with the formula NH₄NO₃. It is a white crystalline solid and is highly soluble in water. What is it used for?

Ammonium nitrate has the chemical formula NH₄NO₃. Produced as small porous pellets, or “prills”, it’s one of the world’s most widely used fertilisers.

Ammonium nitrate has the chemical formula NH₄NO₃. Produced as small porous pellets, or “prills”, it’s one of the world’s most widely used fertilisers.

Lewis said the chemical can be safely stored in its pure form by itself. A Pakistani dealer holds fertilizer containing ammonium nitrate in Multan, Pakistan, on Aug. 25, 2011. Khalid Tanveer / AP file ...

Ammonium nitrate has the chemical formula NH₄NO₃. Produced as small porous pellets, or “prills”, it’s one of the world’s most widely used fertilizers.

Ammonium nitrate has the chemical formula NH₄NO₃. Produced as small porous pellets, or "prills", it's one of the world's most widely used fertilisers.

Ammonium nitrate has the chemical formula NH₄NO₃. Produced as small porous pellets, or “prills”, it’s one of the world’s most widely used fertilisers.