Di-iodates

Potassium di-iodate. Potassium tri-iodate. Potassium molybdamo- Potassiumsulphato-... 

Figs. 16 to 18.—Trimorphism of Potassium Di-iodate, KI03.HI03. 

H. Klinger made the di-iodate by mixing 20 grms. of potassium chlorate, 21 grms. of iodine, and 100 c.c. of water in a half-litre tubulated retort with a thermometer fitted in the tubulure, and the neck directed upwards. The mixture is heated by a small flame. The liquid becomes yellow, and violet vapours condense in the neck of the retort. The materials begin to react at about 85°, and the reaction is complete at about 95°. Only a little chlorine is evolved when the liquid is heated up to its b.p. When the colourless liquid is cooled, crystals of the di-iodate separate, and these can be purified by recrystallization from hot water. The yield is over 70 per cent. Some barium di-iodate can be recovered by adding barium chloride to the mother-liquid. 

When the iodate is crystallized from acid solution, a di-iodate, KI03,HI03, is formed.10 It finds application in the determination of the concentration of hydrogen ions,11 and also in volumetric analysis, since it reacts with potassium iodide and hydrochloric acid according to the equation... 

Figure 4 Packing of nine atoms around the Sr + ion to form a monocapped square antiprism in strontium di-iodate monohydrate. 0(2) designates carboxyl oxygen atoms, and 0(3) and 0(4) are water oxygen atoms (Reproduced by permission from Acta Cryst., 1972, B28, 223)...

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