Can we speak of molecular formulae in describing an ionic salt?
We use molecular formula to describe molecules; however, not all chemical substances are molecular. We would use an empirical formula to describe a 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
On the other hand, there are discrete molecular substances. Ethane consistes of discrete molecules of