Application Limits of HSAB Principle

the exchange reactions in gas-phase between two acid-base complexes have been considered and the reaction energy has assumed as a measure of the stabilization of hard-hard and soft-soft adducts in comparison to the corresponding hard-soft and soft-hard counterparts. The used general scheme for the acid-base reactions during which a base (X), bonded to the hard acid (H+), removes a hard base (OH ) from a soft acid (HO ) is  

With the aim to test the above expanded second derivative compact difference schemes for chemical hardness calculation, in Tables 3.9-3.14 are reported the hardness values for the bases (X=NH3, CH O, H O, CN,  

TABLE 3.9 The Hartree-Fock, B3LYP, SVWN, and BP86/6-31G Chemical Hardness Computations for the [CHjO] Molecule by Using Orbital Energies and Vertical Total Energies for Ionization Potential and Electron Affinity Calculation, Respectively IRHT=intemaUy resolved hardness tensor, H/L=HOMO/LUMO (Putz et al., 2004) 

Other 5.29 from IRHT methock 3.18 from H/L method 6 from EA/fP  

---