Repeating this procedure for all 1181 junctions a remarkable trend emerges. Shown in Figure , the transmissions at the Fermi energy of the full junctions is plotted against that of the cut junctions. For 91% of the molecules the transmission at the Fermi energy is lower than a gap of the same dimensions; for 38% of them by more than an order of magnitude. If we instead chose the lowest transmission between -1.5 and +1.5 eV this trend is even more pronounced, as shown in Figure . From these results it is clear that Si222 is not a special molecule within its class. The majority of molecules in the bicyclo[2. In summary, we have used a high-throughput approach to screen the electron transport properties of the full chemical space of the bicyclo[2.2.2]octane motif based on saturated carbon, permethylated silicon, and permethylated germanium. Like the all-silicon Si222, the members of this class of molecules are extremely insulating due to destructive s-interference in the electronic transmission. We predict there are many members of the class that are even better single-molecule insulators than Si222, holding promise for future experimental efforts. While we have screened the electron transport properties of this prospective class of molecules, it is important to note that other properties remain to be screened in future efforts. The properties of single-molecule junctions depend on a number of factors, such as conformational freedom of the molecule. With complex cyclic and macrocyclic silicon-based molecules as realistic synthetic goals, we think high-throughput computational screening holds great promise for guiding future synthetic efforts by assessing large numbers of prospective molecules.