The pH dependence of five zinc aqua-hydroxo complexes in water solution. a) Molar fraction distribution of particular zinc species as a function of pH. b) Logarithmic plot of the concentration of particular species [17]. Black, red, green, blue and magenta color lines correspond to [Zn(H2O)x]2+, [Zn(OH)(H2O)x-1]+, [Zn(OH)2(H2O)x-2](aq), [Zn(OH)3(H2O)x-3]-, and [Zn(OH)4]2-, respectively.