A three-dimensional iodo-bridged mixed-valence gold(I,III) compound, Cs2Au(I)Au(III)I-6

The title compound, dicaesium gold(I) gold(III) hexaiodide, has a distorted perovskite structure. The crystal contains compressed and elongated [AuI6] octahedra stacked alternately along the [001] and [110] directions by sharing all the corner I atoms. The compound is also characterized by the assembly of the gold complex ions [(AuI2)-I-1](-) and [(AuI4)-I-III](-). The position of the two halogen atoms in (Cs2AuAuI6)-Au-I-I-III is closer to the midpoint between the two Au atoms than in (Cs2AuAuCl6)-Au-I-Cl-III. On the other hand, the distortion from the cubic system to the tetragonal system in the iodide is slightly larger than that in the chloride.