# What causes a eutectic point?

What causes the melting point depression known as a eutectic point?

The temperature depression of a eutectic point can be calculated from the enthaplies and entropies of fusion of the two substances.

• Well, the simple answer would be that, because of the relevant enthalpies and entropies the liquid phase has a lower Gibbs free energy than the tie line connecting the solid phases. Was there a deeper question hidden in there? – Jon Custer Jul 29 '15 at 17:57