# Can we speak of molecular formulae in describing an ionic salt?

Ionic species are definitely non-molecular. They consist of an infinite lattice of postive and negative ions that are held together by strong electrostatic bonds. In common salt, for every sodium cation, there is a correpsonding chloride anion; the charge is balanced by the pairing of postive and negative ions. The simplest formula that represents this is $N a C l$.
On the other hand, there are discrete molecular substances. Ethane consistes of discrete molecules of ${H}_{3} C - C {H}_{3}$. A simpler formula that represented the elemental makeup would be $C {H}_{3}$. However, because we have a very good idea of the mass of the molecule, we present the molecular formula as written.