Molecular Geometry and Structural Formula

Understanding how atoms in a molecules are arranged and how they are bonded together is very important in giving the molecule its identity. Isomers are compounds in which two molecules can have the same number of atoms, and thus the same molecular formula, but can have completely different physical and chemical properties because of differences in structural formula.

Methylpropane and butane have the same molecular formula of C₄H₁₀, but are structurally different (methylpropane on the left, butane on the right).