On the Nature of Bridging Metal Atoms in Intermetalloid Clusters: Synthesis and Structure of the Metal‐Atom‐Bridged Zintl Clusters [Sn(Ge 9 ) 2 ] 4− and [Zn(Ge 9 ) 2 )] 6−

The addition of Sn and Zn ions to [Ge 9 ] clusters by reaction of [Ge 9 ] 4− with SnPh 2 Cl 2 , ZnCp* 2 (Cp*=pentamethylcyclopentadienyl), or Zn 2 [HC(Ph 2 P=NPh) 2 ] 2 is reported. The resulting Sn‐ and Zn‐bridged clusters [(Ge 9 )M(Ge 9 )] q − (M=Sn, q =4; M=Zn, q =6) display various coordination modes. The M atoms that coordinate to the open square of a C 4 v ‐symmetric [Ge 9 ] cluster form strong covalent multicenter M−Ge bonds, in contrast to the M atoms coordinating to triangular cluster faces. Molecular orbital analyses show that the M atoms of the Ge 9 M fragments coordinate to a second [Ge 9 ] cluster with similar orbitals but in different ways. The [Ge 9 Sn] 2− unit donates two electrons to the triangular face of a second [Ge 9 ] 2− cluster with D 3 h symmetry, whereas [Ge 9 Zn] 2− acts as an electron acceptor when interacting with the triangular face of a D 3 h ‐symmetric [Ge 9 ] 4− unit.