|Water is an example of a molecular compound. The hydrogen and oxygen atoms combine to form molecules. |
Many elements combine in a very different way. For example, the compound sodium chloride is not molecular. A single atom of sodium and a single atom of chlorine do not combine to form a molecule.
Instead, many atoms of sodium and chlorine combine together to form sodium chloride particles. We use the word lattice rather than molecule to describe the collection of sodium chloride atoms. The same number of sodium atoms as chlorine atoms combine together to form the sodium chloride lattice so we can still use the formula, NaCl.