Unexpected Solute Occupancy and Anisotropic Polarizability in Lewis Basic Solutions.

Density functional computation revealed that in YOH solvation (Y = Li, Na, and K), the Y cation locates eccentrically at the interstitial hollow site to form the Y·4HO unit, and the hydroxyl adds an excessive electron lone pair ":" to form a OH·HO unit where the hydroxide stays in the the center. The surrounding four oriented HO neighbors interact with the Y through Y ↔ H repulsion and Y:O attraction, causing the Y eccentric dislocation by some 0.80 Å. The ":" turns one O:H-O bond into the O: ⇔ :O super hydrogen bond by altering HO·4HO into HO·4HO. The repulsive Y ↔ H enlarges its separation and the attractive Y:O shortens itself, showing the anisotropic polarization of the Y cation. The anisotropic Y polarizability, O: ⇔ :O compressibility, and the H-O bond contraction of the solute OH distorts the solute bonding network and disperses the O:H-O segmental phonon frequencies, as confirmed spectroscopically.