An Anionic Amido-Substituted Seven-Vertex Siliconoid Cluster.

The silanide [Si 4 {N(SiMe 3 )Dipp} 3 ] - (1) transforms into the anionic siliconoid cluster [Si 7 {N(SiMe 3 )Dipp} 3 ] - (2) with four unsubstituted silicon atoms as a contact ion pair with [K([18]crown-6)] in C 6 D 6 at room temperature within five weeks. Anion 2 was investigated by natural population analysis and visualization of intrinsic atomic orbitals. Magnetically induced current-density calculations of 2 revealed two distinct strong diatropic vortices that sum up in one direction and create a strongly shielded apical silicon atom in 2.