The Kelvin equation [lnS=ln(csc)=vRTD4vss,L] predicts that solubility increases to infinity as the crystal diameter decrease to zero. However for several inorganic salts in water, there are ample experimental evidences showing a maximum in the solubility curve and a solubility that approaches zero as crystal size is reduced to zero. The underlying explanation for this observation is that the surface energy of the crystals depends not only on interfacial tension, but also on surface electrical charge, given by 2q2vs/RTDp4