Moderately reactive molecules forming stable ionic compounds with superhalogens

An explanation of the ability of selected moderately reactive molecules to form stable systems with superhalogens (AlF(4) and AlCl(4)) is provided on the basis of theoretical considerations supported by ab initio calculations. It is demonstrated that even the molecules possessing high ionization potentials (such as SiO(2), NH(3), CHCl(3), CCl(2)F(2)) should form stable and strongly bound ionic compounds when combined with a properly chosen superhalogen system (acting as an oxidizing agent). The conclusion is supported by providing the structural parameters and interaction energies for the SiO(2)AlF(4), NH(3)AlF(4), CHCl(3)AlF(4), CCl(2)F(2)AlF(4), SiO(2)AlCl(4), and NH(3)AlCl(4) compounds obtained at the CCSD(T)/6-311++G(d,p)//MP2/6-311++G(d,p) level. On the other hand, the AlF(4) and AlCl(4) superhalogens were found to be incapable of reacting with molecules whose ionization potentials (IP) exceed 13 eV (e.g., CO(2), CH(4)). Finally, it is demonstrated that the competition between the electron binding energy of the superhalogen system and the IP of the molecule the superhalogen is combined with is a key factor for predicting the stability of certain species.