The consistently larger nitrile average H-bond angles observed in POL MD vs FC MD motivated us to consider how the nitrile is described in both FFs. The AMOEBA FF possesses two signi�icant changes to the electrostatic description from FC MD, i.e., multipoles and polarizability, so we used the model compound oTN to assess whether the electrostatic potential (ESP) maps around the nitrile re�lect these differences (Figure ). We observed that the negative potential around the N atom is narrower in off-axis directions of the nitrile bond in AMOEBA compared to AMBER (Figure ). This is more clearly shown in the difference map for the ESPs between the AMOEBA and AMBER FFs, showing more negative potentials located along the -C≡N bond axis and more positive potentials at angles off the bond axis (Figure ). This indicates that the inclusion of dipoles and quadrupoles in the AMOEBA FF leads to a nitrile with more negative charge density concentrated in front of the -C≡N axis, modelling the nitrile's lone pair, while the purely monopolar nitrile description with the AMBER FF results in a nitrile with a more angularly diffuse negative charge distribution. These results rationalize the strong FF dependence of the average H-bond angles for F28oCNF and F92oCNF's H-bonding populations: more negative potentials along the nitrile bond axis in POL MD leads AMOEBA to a more head-on modelling of the nitriles' H-bond donors' O-H bond dipoles, while more negative potentials off the nitrile bond axis in FC MD leads AMBER to model those same interactions at smaller θCNX's.