Effect of Lone Pairs Lone pairs of electrons contribute to the dipole moment. CH3 H c=9 CH,-N方 CH3 十→ + u=1.5D u=1.9D u=2.9D u=3.9D ammonia water acetone acetonitrile Copyright 2005 Pearson Prentice Hall,Inc.Effect of Lone Pairs  Lone pairs of electrons contribute to the dipole moment