Evidence for Ordered Layers of K+ in KCP (K2 [Pt(CN)4] Cl0.3·3H2O)

Abstract
We have redetermined the crystal structure of K2[Pt(CN)4]Cl0.3·3H2O. It crystallizes in space group P4mm, contrary to earlier assignments. The K+ ions occupy ordered positions in layers with a periodicity of c=5.77 Å which are perpendicular to the c axis. The same kind of superstructure was found for K2[Pt(CN)4]Br0.3·3H2O.