Dark grey (dark red with transmitting light) crystals of heptathallium(I) hexadecaiodo-tribismuthate(III), T1(7)Bi(3)I(16), were obtained by slow cooling of a melt from 800 K to ambient temperature and, with higher crystal quality via solvothermal synthesis in aqueous HI by slowly cooling from 428 to 363 K. The compound is diamagnetic and melts congruently at 630(5) K. X-ray diffraction on single-crystals revealed that T1(7)Bi(3)I(16) crystallizes in the orthorhombic space group Cmcm with lattice parameters a = 2473.4(5), b = 1441.9(2), c = 3616.9(7) pm. The crystal structure can be interpreted as a layered intergrowth of fragments from the CsNiCl3 and K5Dy3I12 structure types with isolated [BiI6](3-) octahedra and [Bi2I10](4-) double octahedra. Rotation and distortion of the complex anions establish coordination numbers (c.n.) between 7 and 9 for the T1(+) cations. Dark red crystals of trithallium(I) hexaiodo-bismuthate(III), T1(3)BiI(6), are only accessible via hydrothermal synthesis in aqueous HI and slowly cooling from 428 to 363 K. Thermal analysis reveals a peritectoid decomposition at 540(5) K into the neighboring phases T1(7)Bi(3)I(16) and T1I. T1(3)BiI(6) crystallizes in the monoclinic space group P2(1)/c with lattice parameters a = 1352.6(3), b = 899.6(2), c = 1353.8(3) pm, and beta = 104.18(3)degrees. In the crystal structure isolated [BiI6](3-) octahedra are arranged according to the motif of a face-centered pseudo-cubic packing. Due to the tilted orientation of the [BiI6](3-) groups the T1(+) cations have c.n. of 8 and 9. Although the crystal structure of T1(3)BiI(6) looks like a. distorted variant of the elpasolith type, there is no symmetry relation according to a group subgroup formalism.

AgBiI4 and Ag3BiI6 were synthesized by solvothermal reaction from AgI and BiI3 in diluted HI-solution (20 %) at a temperature of 160 degrees C. The greyish-black crystals grow as octahedra (Ag-BiI4) or hexagonal/trigonal platelets (Ag3BiI6). AgBiI4 crystallizes in space group Fd (3) over barm with a = 1222.3(1) pm (300 K) and Z = 8 whereas Ag3BiI6 shows the space group R (3) over barm with a = 435.37(6) pm, c = 2081.0(4) pm (300 K) and Z = 1. Both crystal structures show stacking sequence abcabc... of hexagonal layers containing Iodine. Bismuth and silver are sharing octahedral sites with different mass ratio in both structures. The part of silver which could be localized varies with temperature. This behaviour indicates mobility of silver within the crystal structure. The ionic conductivity of AgBiI4 is explored. AgBiI4 and Ag-3. BiI6 show close structural relationship, with AgBiI4 as a variant with a higher degree of order.