Higher order expansion effectively accounts for ΔICOHP variations (and bond changes) in both neighboring and next-neighboring atoms. For corundum and pentoxide systems (Figures and), similar correlations among 4d and 5d TMOs are observed with comparable slopes due to their closely aligned adsorption energies. Again, 3d group, which features magnetic systems, exhibits a comparatively smaller slope. Systems like Hf2O3, Ti2O3, Nb2O5 and Ta2O5 display significant right shifts in the 1 st order correlation linked to large axial(1) bond elongations exceeding 30% (Figures ).