We discuss a chemical interpretation of the charge states of point defects in materials. Notably, we use molecular orbital theory and symmetry principles to guide our understanding of the charge state(s) of a defect, as the framework qualitatively captures the local defect-host interactions leading to molecular orbital states in the electronic structure. The chemical interactions between the defect atom and host atoms can be understood from symmetry principles, as some interactions are forbidden. While the present analysis neglects second-order effects such as lattice distortions and next-nearest neighbor interactions, many of the charge states appearing in the formation energies of native defects in Mg 2 Si are understood qualitatively from the molecular orbital theory framework.