Copper and Silver Heterometallic Iodoantimonates: Structure, Thermal Stability, and Optical Properties.

Seven heterometallic iodoantimonates with the general formula (Cat)2{[Sb2M2I10]} (M = Cu(I) (1-6), Ag(I) (7)) were prepared. X-ray diffraction data indicate that these compounds are the first Sb(III) representatives of the structural type previously known only for heterometallic iodobismuthates(III). In 3 and 4, halogen-substituted cations form halogen bonds with the heterometallic halometalate chain. 1-7 show prominent thermal stability. The estimated optical band gaps lie between 2.16 and 2.40 eV. As in heterometallic iodobismuthates, incorporation of Cu+ rather than Ag+ provides a much lower band gap.