where Pi and Pj are the specific properties of the i th and j th atoms, respectively, d is the Kronecker delta, and dij is the number of bonds separating these two atoms. A RAC can have a "start" in the summation, which constrains the atoms that correspond to the summation starts with i, e.g., the metal, from which we can branch out to generate RACs while "scope" dictates the atoms that are permissible as the ends of these branches, e.g., axial ligands, in the summation starting with atom j. The start definition includes RACs that are metal-centered (mc) (i.e., the metal is the start atom), ligand-centered (lc) which are centered on the coordination atoms of ligand (i.e., the ligand coordinating atoms are the start atoms), or over the full molecule (f). The scope definition includes RACs that span to axial (ax) ligands, equatorial (eq) ligands, or all ligands and the metal. This results in six types of RAC start/scope definitions: f/all, f/ax, f/eq, mc/all, lc/ax, and lc/eq. Each of the five atomic property product RACs (eq. 1) have 6d+6 associated RACs (taking into account the six start/scope definitions), resulting in a total of 30d+30 product RACs. Difference RACs, which are defined as