Question

What is the empirical formula of a compound with the molecular formula `N_2O_4`?

Answer 1

The empirical formula is the SIMPLEST whole number ratio that defines constituent atoms in a species. Does `N_2O_4` satisfy that definition?

Explanation:

Of course, the empirical formula of `N_2O_4` is `NO_2`. Why?

The equilibrium `N_2O_4(g) rightleftharpoons 2NO_2(g)` has been well-studied. Dimerization of `NO_2` to give `N_2O_4` can be rationalized on the basis that the Lewis structure of `NO_2` (with 17 valence electrons!) places a single electron on the cationic nitrogen centre: `""^(-)O-^*N^(+)=O`.