Metal iodides in polyiodide networks - The structural chemistry of complexgold iodides with excess iodine

Theoretical calculations that compare the Ij ion and the [AuI4](-) ion show that they are closely related and have potential energy surface (PES) mini ma corresponding to an L-shaped structure. These calculations also indicate that the I-3(-) and [AuI2](-) ions should be exchangeable. These results w ere confirmed by the synthesis of the compounds (Et3S)[AuI4]. 2I(2) (1) and (Me3S)(2)[AuI4][I-3] (4), which have been characterised by X-ray diffracti on, Raman and far-IR spectroscopy. The structure of 1 is made up of [AuI4]( -) units coordinated by infinite zig-zag chains of I, molecules, and can be regarded as [AuI4](-) ions incorporated into a polyiodide network. The str ucture of 4 is closely related to those of the compounds of the M2Au2X6 fam ily (M = Cs+, Rb+, NH4+, K+; X = Cl-, Br-, I-) which consist of square-plan ar [AuX4](-) and linear [AuX2](-) ions. However, in the structure of 4, the [AuX2](-) ions are replaced by IS ions.