Potassium periodate, KIO₄

The Potassium periodate, KIO₄ is produced by oxidizing a mixture of potassium iodate and hydroxide either electrolytically or with chlorine. It crystallizes in quadratic pyramids, melting at 582° C., and of density 3.618 at 15° C. At 13° C. its solubility is 0.66 gram per 100 grams water. The heat of formation from the elements is 107.7 Cal. In aqueous solution it is converted by potassium iodide into the iodate:

3KIO₄ + KI = 4KIO₃.

From an aqueous solution of the periodate and potassium hydroxide a basic periodate, K₄I₂O₉,9H₂O, crystallizes.