The calculation of the pDOS of Cs in CsCl (Figure ), and the -ICOHP analysis for the Cs-Cs contacts (Table ), propose analogous conclusions to the B2 alkali fluorides. To be noted, the presence of inter-cesium interactions at ambient pressure, have already been observed by some of us in cesium triiodides (CsI3) in a past works, suggesting that cesium might often behave like a 7-valence electron element. Would it be possible to diagnose this feature experimentally? To this point, Sist et al. have measured with x-ray diffraction some peculiar anharmonic vibrational effects in the atomic displacement parameter of cesium, in CsCl, at very low temperature ambient pressure. Anharmonicity is often observed in presence of resonant bonding or lone pairs, and particularly in interaction involving heavy elements. Moreover, charge concentrations resulting from the formation of Cs-Cs interactions, might also be detected through topological analysis of the electron density from high-resolution single crystal x-ray diffraction data. Despite cesium is not typically considered as a 7-valence electron element, especially in absence of extra oxidizing agents or pressure, this is a possibility that should not be excluded. In fact, in favor of the suggestions made by J. B. Goodenough, the "promotion" of semi-core electrons to the valence-shell might not be such an exotic phenomenon, but quite common instead, even at ambient conditions.