Formulas (empirical To Skeletal)

Different formulas answer different questions: Empirical formula -> simplest ratio Molecular formula -> actual number of atoms Structural formula -> how atoms are connected Skeletal formula -> simplified carbon framework The same compound can therefore have several correct representations.

Think of formulas as different levels of detail. Empirical tells the simplest ratio. Molecular tells how many atoms are really in the molecule. Structural tells how they are joined. Skeletal gives a quick simplified drawing of the carbon structure.

The molecular and empirical formulas can be different even for the same compound. For example, C₂H₄ has empirical formula CH₂. Structural representations are especially important in organic chemistry because different compounds can share a molecular formula but have different arrangements of atoms.

A molecular formula specifies composition but does not uniquely define molecular connectivity. This is crucial in organic chemistry because constitutional isomers may have the same molecular formula but different structures. Structural and skeletal notation therefore encode information that cannot be obtained from molecular composition alone.

Empirical = simplest ratio · Molecular = actual atom numbers · Structural = connectivity · Displayed = bonds shown clearly · Skeletal = simplified carbon framework · Same molecular formula can represent different structures · Carbon-bound H atoms are usually omitted in skeletal notation