Bi13Pt3I7: A subiodide with a pseudo-symmetric layer structure

The reaction of PtI2 with Bi and BiI at 630 K yields black, lustrous, air insensitive crystals of the subiodide Bi13Pt3I7 The layered crystal structure (triclinic, C (1) over bar, a=1581.0(2)pm, b=912.6(1)pm, c=2149.6(6)pm, alpha= 90.03(2)degrees, beta=96.96(2)degrees, gamma=90.11(1)degrees, V=3078.6 . 10(6) pm(3)) contains edge-sharing [PtBi8/2] cubes, which form nets of Kagome type. Iodine atoms fill the hexagonal-prismatic voids therein. These (2)(infinity)[(PtBis(8/2))(3)I] layers are alternately separated by layers of iodine atoms or (1)(infinity)[BiI4-] zigzag-chains. The marked pseudo-symmetry of the structure favours stacking faults, which cause streaks of diffuse scattering in the diffraction pattern.