The metal-metal interactions facilitated by semi-core electrons can, in principle, be observed experimentally. This could be achieved through techniques such as high-resolution single crystal X-ray diffraction, which might reveal bond critical points and charge concentrations along the metal-metal contacts. 6) Cesium's Unique Behavior: Cesium exhibits behavior indicative of having seven valence electrons, even at ambient pressure in compounds such as CsCl or CsI3. This suggests that the activation of semi-core electrons might not be as rare as previously thought and could occur under less extreme conditions than assumed.