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

1 Answer
Aug 15, 2016

We use molecular formula to describe molecules; however, not all chemical substances are molecular. We would use an empirical formula to describe a salt.

Explanation:

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 NaCl.

On the other hand, there are discrete molecular substances. Ethane consistes of discrete molecules of H3CCH3. A simpler formula that represented the elemental makeup would be CH3. However, because we have a very good idea of the mass of the molecule, we present the molecular formula as written.