The structural evolution versus oxygen adsorption ↔ desorption of the LnBa2Cu3O6+x series, the influence of rare-earth substitution on oxygen network and copper coordination (CN = 2, 4, 4 + 1, 5) in Bi2Sr2Ca1−yLnyCu2O8 series (Ln = La, Yb; 0≤y≤1) are followed. Images of parent mixed valence oxides, i.e. vanadium bronzes, with their single or double layers structures versus intercalated ions with ideal intergrowth structures like the new Na0.70V2O5 oxybronze are presented. The ability to exhibit double non stoichiometry, i.e. LixV3O8−y (0≤y≤1) in the homologous series LixV3(1+n)O8+7n (0≤n≤∞) is explained.