Crystal structure of aluminium iodate–hydrogen iodate–water (1/1/6) and preparation of anhydrous aluminium iodate

Abstract

The crystal structure of the title compound has been determined by Patterson and Fourier methods using three-dimensional X-ray data and has been refined by a full-matrix least-squares procedure to R= 0.029 for 2 546 observed reflections. The crystals are hexagonal, space group P6₃ with a= 16.107(2), c= 12.378(2)Å, Z= 6. The transformation of the structure to that of anhydrous aluminum iodate (hexagonal, a= 8.97, c= 5.25 Å) is considered. The structure can be formulated as [Al(OH₂)₆³⁺][IO₃^–]·[HI₂O₆^–]·HIO₃ and contains a very short non-bonded oxygen–iodine contact of 2.476 Å.