K 6 (IO 6 H 4 )(HI 2 O 6 )(HIO 3 ) 2 (IO 3 ) 4 ·2H 2 O: A Case of Iodate with Coexisting [I 5+ O 3 ] and [I 7+ O 6 ] Units.

A new alkali-metal iodate, K 6 (IO 6 H 4 )(HI 2 O 6 )(HIO 3 ) 2 (IO 3 ) 4 ·2H 2 O (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 [I 5+ O 3 ] and [I 7+ O 6 ] 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.