The results of our solubility assays summarized

https://www.echemi.com/products/pd20170228091501218-zinc-hydroxide.htmlThe results of our solubility assays are summarized in Table 1, where S represents the total molar concentration of dissolved zinc. Silltn and Martell (3, 4) and Schindler (5) cite earlier investigations. Our results at 25°C are generally consistent with those of earlier researchers, although there are significant differences, especially near the upper and lower ends of the pH range. No earlier solubility data are available for higher temperatures to compare our results with.
We first interpret our solubility results in terms of Zn(OH),(c) in equilibrium with a saturated solution that can contain the Zn(OH)+(aq), Zn(OH),(aq) , Zn(OH), -(aq), and Zn(OH),'-(aq). It is convenient to relate these species to each other and to our solubility data by the following equilibria and corresponding equilibrium constants:
The square brackets above "should" indicate the thermodynamic activity of the enclosed species, but we use molarity instead, which means that the equilibrium constant we estimate is best known as the equilibrium quotient. The results of approximating a z m are discussed later in this article. zinc hydroxide

Another approach is to use all of our solubility-pH data at each temperature to perform computer calculations, resulting in an overall "best" fit of [7] to obtain the desired K value. Different weighting procedures resulted in slightly different K values, but all K values obtained in this way were in good agreement with those already listed in Table 2. For further calculations and comparisons with earlier investigators' results, we will use the values listed in Table 2 as the best that can be derived from our solubility combined with the activity coefficient that we ignore.
Whether or not our K values have the importance we ascribe to them, the use of these K values in [7] does result in calculated solubilities that agree well with the experimental values in Table 1 over the entire temperature and pH range. In this sense, our K value has an uncertainty of a few percent.

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