Why Do Five Ga + Cations Form a Ligand‐Stabilized [Ga 5 ] 5+ Pentagon and How Does a 5:1 Salt Pack in the Solid State?

The reaction of the Ga + source [Ga(PhF) 2 ] + [Al(OR F ) 4 ] − with the neutral σ‐donor ligand dmap (4‐Me 2 N‐C 6 H 4 N) produces the unexpectedly large and fivefold positively charged cluster cation salt [Ga 5 (dmap) 10 ] 5+ ([Al(OR F ) 4 ] − ) 5 . It includes a regular and planar Ga 5 pentagon with strong metal–metal bonding. Additionally, the compound represents the first salt in which an ionic 1:5 packing is realized. We discuss the nature of this structure which results from the conversion of the non‐bonding 4s 2 lone‐pair orbitals into fully Ga‐Ga‐bonding orbitals and the solid‐state arrangement of the ions constituting the lattice as an almost orthohexagonal AX 5 lattice, possibly the aristotype of any 5:1 salt.