I have read in a book that t2g orbitals sometimes account for stability in 3d block transition elements. For example,
- Chromium in 2+ oxidation state shows reducing properties because Chromium in 3+ oxidation state will have half-filled t2g orbitals which will account for extra stability.
- Vanadium has a low value of M+3/M+2 standard electrode potential because of half-filled t2g orbital.
What I have read is that the d orbitals in the absence of ligands have equal energy, and the orbitals split up into eg and t2g due to the presence of ligands. Then how can the half-filled t2g orbitals account for stability, even in absence of ligands?
