The name along with the formula in a molecular compound describe the number of atoms in a molecular compound along with the type that it is. Sometimes even Roman numerals are utilized to distinguish between different ions of transition metals. For example:
LiCl --> Lithium Chloride
PbSO4--> Lead Sulfate
Na3N--> Sodium Nitride
BaO--> Barium Oxide
P2O5--> Diphosphorus Pentaoxide