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Figure 4. Selection and structures of validation ternary oxide materials. A, Selection of X and Y elements in XYO₄ compounds, where the sum of the valences of X and Y is controlled to be eight. Unused elements are labeled gray. B, Optimized structures of nine selected XYO₄ compounds by MELRSNet. From left to right are their side views and top views. The perspective view is at the bottom. Corresponding atoms with their atom number and valence number are labeled in the middle left corner. Four types of bonds are labeled on the side view. C, Optimized bond lengths of selected nine stable materials. Four columns represent four types of bonds in XYO₄ crystals that are explained in Figure 4B. D, Lattice constants of selected XYO₄ crystals. E, Phonon dispersion curves of AlPO₄. F, Phonon dispersion curves of HfBiO₄. G, Theoretical XRD patterns of nine selected materials. ELF image of H, AlPO₄, and I, SnGeO₄ at the planar view. J, Comparison of calculation time based on 32 CPU cores for the PBE functional, HSE06 functional, and LightGBM predictions. MELRSNet: Multistage Ensemble Learning Rapid Screening Network; ELF: electron localization function; CPU: central processing unit; PBE: Perdew-Burke-Ernzerhof; HSE: Heyd-Scuseria-Ernzerhof.