Figure 1: Disproportionation versus cationic cluster formation of univalent group 13 metal salts M+A–.

Generally, the disproportionation is favoured over the cluster formation due to the much higher lattice energies of the M3+(A−)3 salt.
Generally, the disproportionation is favoured over the cluster formation due to the much higher lattice energies of the M3+(A−)3 salt.