Any molecule near the solid/liquid interface will thus have certain number of bonds (in the range 0 to 6) binding it into the solid phase, depending on its exact location. This is shown in the figure.

On the animation, calculate how many bonds have each of the molecules pointed at by arrows. To confirm your answer move the mouse over the corresponding arrow.

Now, molecules attached to the interface (i.e. cubes with at least one "bond") may become "melted off" into the liquid as a result of thermal fluctuations. The molecule will resist this to a degree which depends on the energy with which it is bound to the solid. Since the maximum binding energy (corresponding to a molecule entirely within the solid) is given by the enthalpy of fusion, DH_f, the value for a molecule exposed to the liquid will be nDH_f / 6, where n is the number of bonds.