For RbBi2 this gives λel-ph = 0.82 and for CsBi2 λel-ph = 0.87, both values being indicative of moderate coupling strength Table summarizes the normal and superconducting state parameters derived from experimental measurements. Charge transfer from the Rb/Cs to Bi is evident from the electronic density of RbBi2 and CsBi2 (Fig. ) and the Bader charge analysis yields Rb +0.71 (Bi2) -0.71 and Cs +0.64 (Bi2) -0.64 . This is consistent with electronegativity difference (0.82/0.79 vs. 2.02 for Rb/Cs and Bi in the Mulliken scale, respectively). The density distribution along the Bi-Bi bonds has a strongly delocalized, metallic character. Since charge density is concentrated on the Bi framework, both compounds can be viewed as pyrochlore metals.