Anantharaman and Melius developed an alternative formulation for correcting ∆H f (M, 298 K) that incorporates bond distances from the calculated 3D geometry of the molecule and considers information about neighboring atoms. Equation set (4) shows the details of calculating Melius-type BACs. We have adapted our own notation here to help emphasize and distinguish some parameters. For example, variables with subscripts (e.g., α a ) are fitted parameters (with one parameter per element per level of theory), while variables with superscripts (e.g., S M ) are properties of the atoms, bonds, or molecules such as spin and bond