Ionic species, stabilization energies

Parr and Pearson 1301 defined a parameter 17, which they called "absolute hardness" (17 V4[IP-EA]), and calculated 17 for a variety of neutral and ionic Lewis acids and bases possessing from one to four atoms. These authors showed that the qualitative predictions of the HSAB model regarding the relative reactivities of these species toward one another may be obtained using the results from simple calculations of stabilization energies using 17 and electronegativity values. 

In liquids of low dielectric constant, dispersants tend not to form ionic species in solution, but can form ions in adsorbed films on particle surfaces where acid-base interactions and proton transfer occurs between the particle surface and the dispersant. Particle potentials develop when adsorbed dispersant ions desorb into the organic medium where they become the counter-ions. Zeta-potentials well over a hundred millivolts result from the stronger acid-base interactions. Debye lengths in concentrated dispersions are typically 5 to 20 nm, and the DLVO energy barriers, of ten exceed 25 kT with stability ratios of 10° or more. 

Before we analyze the results obtained for a large variety of compounds, we recall the main formulas we have previously deduced for calculating the stabilization energy of neutral species, molecules and free radicals, and of ionic species, carbocations and carbanions. Furthermore,... 

Finally, the stabilization energies of ionic species may be related to some properties of the corresponding molecules such as their heterolytic bond dissociation energy (HBDE) and their gas-phase acidity (AH°dC,). 

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