To consider molecules as comprising of different fragments is common practice in chemistry. However, there is no unique way to quantum mechanically do so. In principle, the framework we propose herein can make use of any partitioning method, regardless if they are, for example, based on topological analysis of electron densities, or population analysis of wavefunctions. By partitioning into atoms, we can recast the Gibbs free energy expression of a molecule, eq. ( ), as a function of atomic electronegativities: