SUPERSATURATED ZINCATE SOLUTIONS - A STRUCTURAL STUDY

Undersaturated and supersaturated zincate solutions have been prepared electrochemically and chemically, and studied using nuclear magnetic resonance (NMR) spectrometry and extended x-ray absorption fine struct ure (EXAFS). Zn-67 NMR spectroscopy shows only one resonance line, the area of which first increases with the Zn concentration until saturat ion and then remains constant for higher concentrations. EXAFS shows f our oxygen neighbors at a distance of 1.979 Angstrom of each zinc atom . Identical results were obtained with undersaturated and saturated zi ncate solutions. No Zn...Zn correlation was found indicating there is no polymeric species in the supersaturated solutions. It is proposed t hat in zincate solution (KOH 8M) the supersaturation is due to the pre sence of oxodihydroxozincate (ZnO(OH)(2)(2-)).