The low-frequency dielectric dispersion of tolyl xylyl sulfone, pentachlorobiphenyl and hexachlorobiphenyl follow the Davidson-Cole equation for “skewed arc”: ε∗ = ε∞ + ε0 − ε∞/(1+i∞τ0)β (1) rather than the Cole-Cole equation for “semicircular arc with depressed center”. β lay in the range 0.50–0.65. This behavior (with β in the range 0.55–0.65) had previously been observed only for glycerol and propylene glycol.