Nickel iodate, solubility

Nickel Iodate, Ni(I03)2, discovered by Rammelsberg, is interesting on account of its hydrates. The anhydrous salt is obtained as microscopic yellow needles by heating to 100° C. a mixture of nickel nitrate, iodic acid, and nitric acid.3 It is but slightly soluble in water, the solubility decreasing with rise of temperature. 

Other Systems.—In the case of sodium sulphate there is only one stable hydrate. Other salts are known which exhibit a similar behaviour and we shall therefore expect that the solubility relationships will be represented by a diagram similar to that for sodium sulphate. A considerable number of such cases have, indeed, been found, and in some cases there is more than one metastable hydrate. This is found, for example, in the case of nickel iodate, the solubility curves for which are given in Fig. 76. As can be seen from the figure, suspended transformation occurs, the solubility curves having in some cases been followed to a considerable distance beyond the transition point. One of the most brilliant examples, however, of suspended transformation in the case of salt hydrates, and the sluggish transition... 

Fio. 23.—Solubility Curves of the Cobalt Fio. 24.—Solubility Curves of the Iodates. Nickel Iodatea. 

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