To understand the effects of spin on adsorption and ICOHP, it is instructive to compare two isoelectronic systems: one in high-spin (HS) and one in the low-spin (LS) configuration. For this purpose, we have selected vanadium and tantalum oxides. metal active site in the +5, d 0 configuration, i.e, in a low spin (LS) state. The rest of the V atoms in slab are in +3 high spin (HS) however. On the other hand, axial(1) bond ICOHP energy is reduced (bond elongation) (blue), while equatorial bonds remain largely unchanged (brow/gray).