Untersuchungen an Polyhalogeniden, V [1] Darstellung und Kristallstruktur des Tetrammin-palladium(II)-oktaiodids, [Pd(NH3)4]I8 / Studies on the Polyhalides, V [1] Preparation and Crystal Structure of [Pd(NH3)4]l8

Abstract

The new compound [Pd(NH3)4]l8 crystallizes monoclinically in the space group P21/m with a = 959.0 pm, b = 835.4 pm, c = 1301.1 pm, β = 103.37° and Z = 2 formula units. The crystal structure has been solved by 'direct methods' and refined to R = 0.057 with 1357 observed reflections. The structure consists of quadratically coordinated cations [Pd(NH3)4]2+ and planar, Z-shaped and completely ordered octaiodide anions I8 2-. According to the sequence of interatomic distances d(I-I) = 295.0 pm, 289.9 pm, 336.2 pm, 279.1 pm, 327.0 pm, 339.3 pm, 273.8 pm the anions may be described as [I3- • I2 • (I- • I2)]- The iodide-iodine sides (I- • I2) are joined with the distance d(I---I) = 364.1 pm to a slightly bent triiodide chain being part of an octaiodide ribbon 1 ∞[I8 2-]- Next contact spacings between neighboring anions start at d(I---I) = 403.7 pm