Sodium iodate, NaIO₃

The Sodium iodate, NaIO₃ is a constituent of Chile saltpetre or sodium nitrate, and remains in the mother-liquor after crystallization of the nitrate. It is an important source of iodine. The salt can be prepared by oxidizing sodium iodide with sodium peroxide or by the electrolytic method, and also by the interaction of sodium iodide and periodate. It forms white crystals.

The density of the iodate is 4.277. At 20° C., 100 grams of water dissolve 9.1 grams, and at 100° C., 33.9 grams. Ditte gives 105° C. as the boiling-point of the saturated solution in contact with the solid. It yields a pentahydrate, stable between -2° and +22° C.

References to work on the molecular depression of the freezing-point and on the electric conductivity of dilute solutions are appended.