Cerium, praseodymium, and terbium stand out among other rare-earth systems because they exhibit two possible oxidation states that produce a series of anion deficient phases that are fluorite-related and have a generic formula Ln_nO_2n-2. Since the seminal works of Eyring, and the valuable contributions of many other scientists, many of the occurring phases were determined using scattering techniques. It was then possible to propose a paradigm for the particular oxygen vacancy order that is observed in most of these phases We would like to discuss how the structural characteristics of these systems can affect their radiation tolerance. In this contribution, we analyze using Bader’s analysis the charge density and the chemical bonds of the A-type, B-type, and the iota phase, which corresponds to the generic compound formula with n=7. Then we try to correlate these results with irradiation experiments on simple lanthanide oxides and with the behavior of the broad family of delta phases that are pseudo-binary compounds with generic formulas A_6BO_12 or A_4B_3O_12 that share many structural features.