On the Theory of Phase Transitions

The question about continuous phase transitions (without latent heat) is investigated from the general thermodynamical point of view. In doing this, it becomes clear that such transitions can take place when the symmetry of the lattice changes. There are two possible types of transition, namely: (1) Curie points with a discontinuity in the specific heat which lie on a curve in the p, T -diagram, (2) isolated points in the p, T -diagram which lie in a certain way on intersections of curves of normal phase transitions.