where Q is the charge on each of two atoms separated by a distance, r.22 Dipole moments
of diatomic molecules can be calculated directly. In more complex molecules,
vector addition of the individual bond dipole moments gives the net molecular dipole
moment. However, it is usually not possible to calculate molecular dipoles directly from
bond dipoles. Table 3-7 shows experimental and calculated dipole moments of
chloromethanes. The values calculated from vectors use C-H and C-CI bond
dipoles of 1.3 and 4.9 X C m, respectively, and tetrahedral bond angles. Part of
the discrepancy arises from bond angles that differ from the tetrahedral, but the column