K6(IO6H4)(HI2O6)(HIO3)2(IO3)4·2H2O: A Case of Iodate with Coexisting [I5+O3] and [I7+O6] Units

A new alkali-metal iodate, K6(IO6H4)(HI2O6)(HIO3)2(IO3)4·2H2O (KIOH), was successfully grown at room temperature by a slow evaporation method. To our knowledge, the title compound is the first alkali-metal iodate containing isolated [I5+O3] and [I7+O6] units in one structure. Both the bond valence sum and X-ray photoelectron spectroscopy confirmed this phenomenon, which is consistent with the single-crystal data. Also, the theoretical calculation results showed that the title compound is a potential birefringent material. What is more, the low-cost growth of centimeter-sized crystals for the title compound greatly enriches the structural chemistry of the iodate system.