Polycations Stabilised by Borosulfates: [Au 3 Cl 4 ][B(S 2 O 7 ) 2 ] and the One-Dimensional Metal [Au 2 Cl 4 ][B(S 2 O 7 ) 2 ](SO 3 ).

(SO 4 )-rich silicate analogue borosulfates are able to stabilise cationic cluster-like and chain-like aggregates. Single crystals of [Au 3 Cl 4 ][B(S 2 O 7 ) 2 ] and [Au 2 Cl 4 ][B(S 2 O 7 ) 2 ](SO 3 ) were obtained by solvothermal reaction with SO 3 , and the electronic properties were investigated by means of density functional theory-based calculations. [Au 3 Cl 4 ][B(S 2 O 7 ) 2 ] exhibits a cluster-like cation, and the cationic gold-chloride strands in [Au 2 Cl 4 ][B(S 2 O 7 ) 2 ](SO 3 ) are found to resemble one-dimensional metallic wires. This is confirmed by polarisation microscopy.