Two internal structures
Both ions contain covalent bonds inside them.
Ionic attraction organizes the cations and anions into the solid.
Ionic solid · ammonium nitrate salt
Ammonium nitrate
NH₄NO₃
Ammonium nitrate is NH₄NO₃, an ionic solid composed of NH₄⁺ and NO₃⁻. Both ions are polyatomic: ammonium has covalent N–H bonds, while nitrate has a resonance-delocalized N–O framework.
Safety-relevant chemistry: ammonium nitrate is an oxidizing salt and can participate in hazardous reactions under inappropriate conditions. This page covers identity, structure and solution chemistry only.
Essentials
NH₄NO₃ is one ammonium ion plus one nitrate ion.
The +1 and −1 charges balance in a 1:1 formula unit. The formula is not a chain of nine atoms joined by ordinary covalent bonds.
Detail
Ammonium is tetrahedral; nitrate is trigonal planar.
The two ions have very different local geometries even though both are built around nitrogen. Ammonium has four N–H bonds; nitrate has three delocalized N–O positions.
Same element, different environment
Nitrogen appears in two chemically different ions.
Oxidation state, bonding and geometry differ strongly between NH₄⁺ and NO₃⁻.
Understand
Dissolution separates the ionic lattice into hydrated ions.
Water solvates NH₄⁺ and NO₃⁻. The dissolution process absorbs heat under ordinary conditions, which is a bulk thermodynamic effect rather than a change in chemical identity.
Acid–base side
NH₄⁺ can donate a proton weakly in water.
Nitrate is the conjugate base of a strong acid and is correspondingly very weak as a Brønsted base.
Reference identifiers
Names and identifiers that pin down the chemical identity.
| Formula | NH₄NO₃ |
|---|---|
| CAS Registry Number | 6484-52-2 |
| Ions | NH₄⁺ and NO₃⁻ |
Advanced
Push past the first model without losing the simple picture.
Is NH₄NO₃ a molecule?
No. The solid is ionic and is represented by formula units.
Why are there two nitrogen atoms with different behavior?
One belongs to ammonium and one to nitrate; their bonding, charge and oxidation-state environments are different.
Does endothermic dissolution mean the compound is unstable?
No. Heat flow during dissolution and chemical stability are different concepts.
Constituent elements