For isolated molecules, guidelines exist that rely on the molecular formula to tailor the frontier (highest occupied or lowest unoccupied) molecular orbital energy levels and optical absorption ...

You can work out the molecular formula from the empirical formula, if you know the relative mass formula (M r) of the compound. Add up the atomic masses of the atoms in the empirical formula.

Both have a molecular formula of \({C_4}{H_{10}}\). The structural formulae are different though, so they are isomers of each other. Polar and ionic compounds tend to be soluble in polar solvents ...