Calculations on complexes of AlCl3 with acetyl chloride and benzoyl chloride have predicted that the relative stabilities are in the order O bound > neutral Cl bound > ion pair. In the case of benzyl chloride, the results are neutral Cl bound > ion pair. Complexes between Al2Cl6 and the acid chlorides predict the O bound complex once again to be more stable than the ion pair. However, in this case no neutral Cl bound species is present as a Cl- is sponaneously transferred to form the ion pair complex. For benzyl chloride, the neutral Cl bound may be more stable than the ion pair. An analysis of the possible pathways for the formation of organic cations involved in Friedel-Crafts reactions implies that ion pair complexes involving dimeric Al2Cl6 may provide a lower energy route to Rf formation. This is in contrast to the assumed role of monomeric AlCl3 complexes.