# What is the formula of a molecular compound?

Let us consider $\text{empirical formula}$ versus $\text{molecular formula}$.
The $\text{empirical formula}$ is the simplest whole number ratio defining constituent atoms in a species. Given say a $\text{molecule}$ of ${N}_{2} {O}_{4}$ or ${C}_{2} {H}_{6}$...the empirical formulae are $N {O}_{2}$ and $C {H}_{3}$ by the given definition.
And of course, the $\text{molecular formula}$ is a whole number multiple of the $\text{empirical formula}$...in general combustion analysis gives us %C;H;N...and we can use this to approach the empirical formula. For the molecular formula we need a determination of molecular mass.