Discussion on the formation and bonding in three [Ga8R10] compounds: the diversity in classical Ga-Ga bonds

Herein we describe three Ga(8) compounds that feature gallium atoms in an oxidation state of 1.25 with normal valent 2e-2c bonding. Their structures and the influence of their ligands (phosphorus and nitrogen atoms directly bonded to the Ga(8) moieties) are discussed on the basis of DFT calculations, providing an insight into a probable mechanism for insertion reactions between GaX and GaX(3) species that lead to a reaction cascade via halides like Ga(2)X(4) and Ga(5)X(7) to Ga(8)X(10) and Ga(8)X(12) (2-), respectively. Finally, the Ga(8) cores of the three title compounds were compared with the topology of carbon atoms in C(8) alkanes.