Class 2 dielectrics are made from Barium Titanite which is a ferroelectric material. The crystal structure of Barium Titanite contains barium atoms at the corners, oxygen atoms at the face centers, and a titanium ion in the center. When the dielectric is above 130°C, the crystal structure becomes cubic and the titanium ion is at the center of the cubic structure. When the dielectric cools below 130°C, the titanium ion will shift within the crystal structure and take on a tetragonal shape. The shifting ion creates a positive charge on one end of the crystal structure and a negative charge on the other, which results in a dipole. A dipole is just a positive and negative charge separated by some finite distance. Each dipole has its own electric field going from the positive side to the negative side. The temperature at which the dielectric material changes from a tetragonal shape to a cubic shape is called the curie point.