Undercoordination resolved bond relaxation and O:H–O potentials.^[1,82,85] (a) BOLS formulation of atomic undercoordination-resolved bond contraction (z < 12), with m > 0 being the bond nature index. (b) O:H–O potential paths for the sized (H₂O)_N = 2 – 6 clusters (Δd_H < 0, ΔE_H > 0; Δd_L > 0, ΔE_L > 0). The blue dots in (b) are the initial equilibrium for N = 6.