Phase diagram analysis
Assuming that the fields marked by x are solid and y is liquid, these are the points:


a: eutectic point. Cooling will turn the single liquid into two solids. The point is between the composition of the two solids involved.
b: eutectoid point. Cooling will turn the single solid into two solids.
c: peritectic point. Cooling from immediately to the left will turn the solid into a liquid and a solid. The point is outside the composition of the two solids involved.
d: congruent point: A solid will melt at this point to a liquid of the same composition.
e: incongruent melting points. A solid will melt to a liquid and a solid. Note that the left one is intimately associated with the peritectic point.


There are no peritectoid points in this diagram. A peritectoid point is similar to a peritectic point, but with all phases solid.