# Why is the melting point of an object inversly proportional to pressure?

In my science book it is written that as the pressure increases the melting point of a solid decreases but i think that it is wrong as the pessure will make the molecules stick together instead of flowing like liquid thus increasing the melting point right? So my book is wrong right?

• What does it mean that this point "decreases" ? – Tom-Tom Apr 27 '15 at 8:49
• A comment about the title: "as the pressure increases the melting point of a solid decreases" does not compel the relation to be one of inverse proportionality. – AV23 Apr 27 '15 at 13:11

• A different way to phrase it: The full Gibbs free energy formulation includes $PV$. Since a first order phase transition requires a change in volume, there is a $P \Delta V$ factor. Thus, depending on the sign of $\Delta V$, higher pressures may either help or hinder the phase transition. – Jon Custer Apr 27 '15 at 15:36