Question

Is ammonium ion a radical?

Answer 1

`"Ammonium ion"` is not a radical species............

Explanation:

The ammonia molecule, `:NH_3` is conceived to have a lone pair of electrons localized on the nitrogen centre.

In aqueous solution, this lone pair is conceived to donate to an hydrogen ion in an acid base reaction as shown:

`NH_3(aq) + H_2O(l) rightleftharpoons NH_4^(+) + HO^-`

All chemical reactions conserve charge. Has charge been conserved here?

Certainly, we can measure the extent of this equilibrium reaction (conveniently by measuring the `pH` of the solution:)

`K_"eq"=([NH_4^+][HO^-])/([NH_3])=10^(-4.75)=1.78xx10^-5`.

In ammonium cation, there are SIX electrons associated with nitrogen, rather than the 7 required for neutrality. The nitrogen in ammonia is (so-called) quaternized, and thus bears a positive charge. Certainly, we can use ammonium salts such as `NH_4Cl`, and `(NH_4)_2SO_4` in the lab.

`"Ammonium nitrate"`, when mixed with fuel oil, is a potent high explosive.