Der erste Vertreter des K2PtCl6-Typs bei Fluoriden A2[PtF6]: β-Cs2[PtF6]

The First Fluoride A₂[PtF₆] of the K₂PtCl₆ Type: β-Cs₂[PtF₆] For the first time, yellow cubic single crystals of Cs₂[PtF₆] have been obtained by solid state reaction, heating (Pt-tube, 35 d, 800°C) the fluorination product of an intimate mixture of (NH₄)₂PtCl₆ and 2 CsCl (diluted F₂, F₂:N₂ = 1:5, 10 d, 400°C). The new form is isostructural with K₂PtCl₆: Fm3 m; a = 905.5(2) pm; Z = 4 (Guinier-de Wolff data, CuKα₁); R = 2.32% (SHELX-76); 1398 I₀(hkl), Image-Plate diffractometer data (Stoe IPDS). It is compared with already known α-Cs₂[PtF₆] (K₂GeF₆-type, P3 m1). The Madelung-Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, and Mean Fictive Ionic Radii, MEFIR, are calculated and discussed in comparison with the data of further Hexafluoroplatinates(IV). A complete analysis of MAPLE was carried out for the title compound as well as for the α- and a hypothetical α′-form.