For this property, Group 4 is debatably the peak performer, whereas Group 6 DFAs produce catastrophic ΔEe(rxn) predictions, many in error by over 50 kcal mol -1 . Although the Group 6 DFAs do yield the best ω5(H-C-N bend) results, DFAs spanning the DFT ladder widely exaggerate this frequency and ultimately misrepresent the critical feature of the quasilinear/quasibent conundrum. Contradictory to expectations, Group 1 is statistically the best performer for both re(N-O) and ω3, but results are too scattered for applications that demand high accuracy, such as spectroscopy and chemical bonding theory. The DFT ladder is largely successful for Δre(H-C), with large reductions in spread and generally more accurate medians with group improvements.