Abstract: | Platinum Iodides PtI2 and Pt3I8 Powder samples of tetragonal Pt3I8 (a = 1166.4(1); c = 1068.2(2) pm) and the cubic α-form of PtI2 (a = 1109 pm) were obtained by thermal decomposition of PtI4 in closed quarz ampoules at a I2 pressure of 2–3 bar and 8 bar, respectively, and at 320°C and 430°C and 430°C, respectively. Single crystals of the monoclinic α-Form of PtI2 (a = 658.77(6); b = 871.50(34), c = 688.94(11) pm; β = 102.76°; Z = 4) were formed by hydrothermal synthesis from PtI4, KI, and I2 at 420°C. In the crystal structure of β-PtI2 two square planar PtI4-units are connected by a common edge to planar Pt2I6 groups which are linked by common corners to puckered layers. Crystals of Pt3I8 synthesized by hydrothermal synthesis from PtI4, KI, and I2 at 350°C were twinned and showed defects. As the result of X-ray studies the compound can be formulated as a mixed-valence platinum(II,IV) iodide PtI4 · 2 PtI2. Octahedral PtI6 and square planar PtI4 units are linked together to a three dimensional skeleton. |