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.

Polycations Stabilised by Borosulfates: [Au3 Cl4 ][B(S2 O7 )2 ] and the One-Dimensional Metal [Au2 Cl4 ][B(S2 O7 )2 ](SO3 ).

(SO4 )-rich silicate analogue borosulfates are able to stabilise cationic cluster-like and chain-like aggregates. Single crystals of [Au3 Cl4 ][B(S2 O7 )2 ] and [Au2 Cl4 ][B(S2 O7 )2 ](SO3 ) were obtained by solvothermal reaction with SO3 , and the electronic properties were investigated by means of density functional theory-based calculations. [Au3 Cl4 ][B(S2 O7 )2 ] exhibits a cluster-like cation, and the cationic gold-chloride strands in [Au2 Cl4 ][B(S2 O7 )2 ](SO3 ) are found to resemble one-dimensional metallic wires. This is confirmed by polarisation microscopy.