fig6

Figure 6. Bonding and charge disorder analysis in RE₃TaO₇ and RE₂Zr₂O₇ oxides. (A) Relative bond lengths for RE–O (left) and Zr/Ta–O (right) polyhedra, where “REO₇”, “REO₈” and “REO_7/8” denote the 7- and 8-fold and mixed-coordination RE–O environments. Insets illustrate representative polyhedral units; (B) Bond-length disorder degree D_b of RE–O (left) and Zr/Ta–O (right) polyhedra, using the same symbol scheme as in (A); (C) Valence charges of cations RE³⁺ (left) and anions O^2- (right), derived from Bader charge analysis; (D) Valence charge disorder degree D_e for RE³⁺ (D_e^RE) and O^2- (D_e^O), quantifying charge inhomogeneity within coordination polyhedra. RE: Rare-earth.