In some ferroelectric crystals, the temperature dependence of the dielectric constant can be reasonably accurately represented by the Curie-Weiss law,
         ε - ε₀ = C/(T-T₀) ------------------------- [3345]
where,
         C -- The Curie constant.
         ε -- The permittivity of the material.
         ε₀ -- The permittivity of vacuum.         
         T₀ -- The Curie-Weiss temperature, which in general differs from the Curie temperature (T_c).

Equation 2382a indicates that when the temperature of the crystal is close to T₀, the dielectric constant becomes very large.

In some ferroelectrics, T_c is aproximately equal to T₀, while in others T_c is far from T₀.