Isopropyl and tert-butyl are both types of alcohol molecules with different structures. Isopropyl has a linear structure with two carbon atoms, while tert-butyl has a branched structure with three carbon atoms. This difference in structure affects their chemical properties and applications. Isopropyl alcohol is commonly used as a solvent and disinfectant, while tert-butyl alcohol is often used as a solvent in organic reactions due to its steric hindrance. Overall, the main difference lies in their structures and how they interact with other molecules in chemical reactions.