Cover Picture (Angew. Chem. Int. Ed. Engl. 12/1995)

The cover picture shows the crystal structure of the elevenfold positively charged cation [Ba 6 Li 3 O 2 ] 11+ , in which a Ba 6 O octahedron and a Li 3 Ba 3 O prismane are connected through a shared Ba 3 triangular face. A density functional calculation of 33 centers and 460 electrons (!) suggests that this is a thermodynamically favorable polyion aggregate containing weakly coupled O 2‐ centers. Eleven tert ‐butyl alcoholate anions and three tetrahydrofuran solvent molecules provide kinetic shielding. The lipophilic wrapping by the largely impenetrable hydrocarbon skin (C 56 H 123 ) anchored by O centers also limits the cluster size, as is confirmed by the structure of the hexameric sodium tetraphenylimidodiphosphate, which in its outer sphere contains 24 phenyl rings. The lipophilically wrapped polyion aggregates form by a self‐organization principle for sterically overcrowded molecules so far not systematically exploited, in which the size of the thermodynamically stabilizing polyion core depends on the space within its lipophilic covering. A more detailed report is provided by H. Bock, E. Herrmann, N. Rösch, et al. on pages 1353 and 1355. The cover picture was prepared by R. Utermark, Hoechst AG (Frankfurt am Main, Germany).