Calcium fluoride solutions with Al3+, Yb3+and La3+fluorides were studied using the ITC technique. The observed relaxations at 130K and 210K were assigned to dipoles nnRs3+-F−i(Rs= La or Yb) and to the L-shape clusters respectively. A band at 360K, due to big clusters of dipoles, was found in the Yb3+doped samples and in the matrices with Al3+together with La3+. Only the presence of Al3+in the calcium fluoride is not sufficient to produce dipoles, but association with La3+or Yb3+aids the aggregation of dipoles forming big clusters. A Maxwell-Wagner-Sillars relaxation originates a peak at 290K, which is observed in almost all samples, including the pure one.