Electron population analysis on RbBi2 shows that the DOS(EF) is contributed mostly by electrons occupying nearest-neighbor Bi-Bi antibonding states (see Fig. of the Supplementary Material). A hypothetical neutral Bi pyrochlore lattice would have its EF lying close to a pseudogap. The two electrons donated by Rb increase the antibonding population, destabilizing the lattice. Unfortunately, with the currently available computational tools (either direct in case of local basis set or indirect -via projection of plane-wave wavefunctions to a local orbitals set ) the bonding population analysis can only be performed in a scalar-relativistic case. While for bonding of lighter elements SR approximation is reasonably applicable, the chemical bonding in 6 th and 7 th period elements is heavily influenced by SOC effects . A possible solution for reliable population analysis of compounds of the heaviest elements is via the localized Wannier spinors .