RC1 is not considered in this work, as it is defined as a basic error-canceling reaction but not necessarily an isodesmic reaction, since the number of each bond type is not always conserved propylene are treated as different bond types. Finally, RC4 adds the further constraint that the identity of the neighboring atoms (i.e. atoms who are also bonded to at least one of the atoms in the original bond in question), as well as their own coordination numbers must also be conserved. The interested reader should see Buerger et al. for excellent examples and illustrations that make the distinctions between these reaction classes clear.