Stabilizing the Homopolycation (I4 )2+ with a Hexasulfate in (I4 )[S6 O19 ] and a Borosulfate in (I4 )[B(S2 O7 )2 ]2

The reaction of elemental iodine and SO3 in a sealed glass ampoule yielded a turquoise-colored solution. At temperatures below 7 °C, deep red crystals of (I4 )[S6 O19 ] grow. With the addition of B2 O3 and pyridine-SO3 complex red crystals of (I4 )[B(S2 O7 )2 ]2 can be obtained after heating the mixture to 120 °C. The combination of an (I4 )2+ cation with oxoanions has previously not been observed. Both anions have a significant but different influence on the structural properties of the (I4 )2+ cation.