Theoretical chemistry is a branch of chemistry which deals with the study of chemical properties and the fundamental principles governing the behavior of chemical systems using mathematical models and computational methods. It can also be referred to as mathematical chemistry, computational chemistry, or theoretical chemical physics. Mathematical chemistry emphasizes the use of mathematical tools like graph theory and combinatorics to analyze chemical phenomena. Computational chemistry involves the use of computer simulations to predict chemical properties. Theoretical chemical physics focuses on the understanding of chemical processes using quantum mechanics. Regardless of the term used, these areas of study are all unified in their goal of understanding chemistry through theoretical analysis.