A Three-Dimensional Iodo-Bridged Mixed-Valence Gold(I, III) Compound, Cs₂Au^IAu^IIII₆

The title compound, dicaesium gold(I) gold(III) hexaiodide, has a distorted perovskite structure. The crystal contains compressed and elongated [AuI₆] octahedra, which are 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, [Au^II₂]^- and [Au^IIII₄]^-. The position of the two halogen atoms of Cs₂Au^IAu^IIII₆ is closer to the midpoint between the two Au atoms than in Cs₂Au^IAu^IIICl₆. On the other hand, the distortion from the cubic system to the tetragonal system in the iodide compound is slightly larger than that in the chloride.

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