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 structure (EXAFS). Zn-67 NMR spectroscopy shows only one resonance line, the area of which first increases with the Zn concentration until saturation and then remains constant for higher concentrations. EXAFS shows four oxygen neighbors at a distance of 1.979 Angstrom of each zinc atom. Identical results were obtained with undersaturated and saturated zincate solutions. No Zn...Zn correlation was found indicating there is no polymeric species in the supersaturated solutions. It is proposed that in zincate solution (KOH 8M) the supersaturation is due to the presence of oxodihydroxozincate (ZnO(OH)(2)(2-)).