Lithiation of tris(methylamino)methylsilane using an excess of n -butyllithium affords the corresponding trifunctional lithium amide in high yield. The compound crystallizes from tetrahydrofuran as a dimer with six donor molecules: [MeSi(NMeLi)3]2(thf)6}. The cluster is a cage structure grouped around a crystallographic center of inversion. The silicon and lithium atoms are tetrahedrally tetracoordinated, but the nitrogen atoms are pentacoordinated and have a square pyramidal environment of one carbon, one silicon, and three lithium atoms. Parallels can be drawn to other species with polymetallated nitrogen functions. An analogous compound was prepared from tris(methylamino)vinylsilane.